Library

Notes: 3-O-benzyl (and 3-O-methyl)-1,2-O-isopropylidene-α-D-xylo-dialdo-1,4-furanoses treated with bromocyanomethylidene- or bromoacylmethylidene-triphenylphosphoranes gave in good yields the corresponding olefinic sugars. These compounds, which bear three adjacent electrophilic carbon atoms (C(5), C(6), C(7)) constitute useful synthetic intermediates in carbohydrate chemistry. They represent, for example, good starting materials for the preparation of 3-glycosylisoxazoles, 5-glycosylisoxazoles and 2-glycosylthiophenes.

Notes: Formation of strongly colored complexes of Cu+ with glyoxal-bis-(N-t-butylimin) (GLI) is observed in acetonitrile. Optical measurements reveal two complexes, Cu(GLI)+ (ṽmax = 26.0 kK, δ = 2800) and Cu(GLI)2+ (ṽmax = 19.3 kK, ε = 8530). The equilibrium constants (0.1M tetraethylammoniumperchlorate) are logK1 = 3.9 and logK2 = 2.5. The equilibrium data are confirmed by potentiometric measurements with a copper electrode. In O-donor solvents, only the 1:2 complex is observed. Cu(GLI)2CIO4 can be crystallized as a dark red solid which is stable towards atmospheric oxygen.

Notes: The orientation of the cycloaddition of diazomethane on unsaturated branchedchain sugars has been studied. For 3-C-cyanomethylidene-3-deoxy-1,2-O-isopropylidene-α-D-glycero-tetrofuranose the orientation was ‘normal’ and did not depend on the configuration at the double bond. The same situation prevailed with derivatives of 3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-methylidene-α-D-xylo-hexofuranose. For the 3-C-acylmethylidene- and the 3-C-cyanomethylidene-3-deoxy-1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranoses, the trans-(H-C(3′)-C(2))-isomer gave the ‘normal’ cycloadduct whereas the cis-isomer gave predominantly the αabnormal spiro-pyrazoline. This observation represents the first instance where the regioselectivity of a cycloaddition reaction is affected by the geometrical isomerism of the dipolarophile. The most probable explanation of the phenomenon is the conformational perturbation about the C(4)--C(5) bond of the unsaturated sugars induced by a change in the configuration at C(3). The consequence of that ‘conformational transmission’ of a difference in configuration at C(3) is that the steric crowding on the cis- than in the trans-isomer. Several novel examples of a new series of C-glycosylidenic derivatives, the spiro-pyrazolines, are described.

Notes: The stability constants of the Ni2+ and Co2+ complexes with 1,5-diazacyclooctane-N,N′-diacetic acid (H2DACODA) have been determined potentiometrically in 0.5M KNO3 at 25°. Only M(DACODA) and M(DACODA)OH- were observed.In addition the formation and dissociation kinetics of the pentacoordinate complexes M(DACODA) has been studied in aqueous solution using a stopped-flow technique. Formation follows the rate law vf = kf [M2+] [HDACODA-]/[H+], which can be interpreted as a bimolecular process either between M2+ and DACODA2- (kM,LML) or between MOH+ and HDACODA- (kMOH,HLML). The second order rate constants kM,LML are much higher than those expected from water exchange and can only be explained by a strong internal conjugate base effect. In the limiting case, however, this is equivalent to the second possible explanation, which assumes MOH+ and HDACODA- as reactive species. The dissociation rate is given by vd = (kML + kHML [H+]) · [M(DACODA)].

Notes: The 13C-NMR. spectra of a series of tri-n-alkyl arsenic complexes of platinum and palladium have been measured. In these complexes it is suggested that the carbon chemical shift of the atom bound directly to the arsenic is a useful structural probe. The chemical shift of the second carbon atom in the chain is interpreted in terms of interactions within the chains of anyone ligand. The values 2J(Pt, C) and 3J(Pt, C) are presented.

Notes: 3,5-Diamino-4-phenylazo-pyrazoles (1a-1c) react with acetylacetone and with ethyl acetoacetate to yield the corresponding pyrazolo[1,5-a]pyrimidine derivatives 2a-2c and 3a-3c, respectively.Whereas 1a-1c add readily to methyl acrylate yielding the 4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidine derivatives 5a-5c, 1a-1c add to methylacrylonitrile or methyl methacrylate only under drastic conditions to yield 5d-5f. The pyrimido[1,2:2′,3′]pyrazolo[1,5-a]pyrimidine derivatives 10a-10c are prepared by the action of acrylonitrile on 2a-2c. Compounds 10a-10c are readily converted into the corresponding oxo derivatives 12a-12c on treatment with acetic acid-hydrochloric acid mixture.

Notes: 2-Aza-1,3-dienes. 2. Synthesis and Structure of a Stable Azomethine-ylid.Thermal treatment of 2-(2′-cyano-2′-methoxycarbonyl)methylide-amino-1-morpholino-cyclohexene results in the formation of a stable isomere. Its azomethine-ylid structure is demonstrated from the spectroscopic data (UV., IR., 1H- and 13C-NMR.). 1,3-dipolar cycloaddition reactions of this ylid leads to spiropyrrolines.

Notes: Synthesis of Nonactin.The macrotetrolide antibiotic nonactin (I), containing four units of a C10 hydroxy acid, has been synthesized starting from two adequately protected derivatives (III and IV) of nonactic acid (II). The 32-membered ring of the macrotetrolide is built up by a sequence of condensation and deprotection steps leading first to a product with two, and subsequently to one with four nonactic acid residues (VIII) which is then cyclized in the presence of Ag+-ions. Two reactions forming ester bonds have been developed to condense the hydroxy acids and to effect the final cyclization. In one the activation of the carboxyl group is achieved by conversion into the mixed anhydride with 2,4,6-trimethylbenzene sulfonyl chloride in pyridine. In the other the Ag+-ion induced reaction of a S-(2-pyridyl) hydroxy carbothioate is used to form the corresponding macrocyclic lactone. In the case of nonactin the ring closure is promoted by the coordinating effect of Ag+-ions present in the reaction mixture.

Notes: The results of this study show that three parameters are sufficient to describe the selectivity behaviour of nitrations influenced by mixing as long as a fast combination of the reactant solutions takes place and fast agitation is employed. This is in full agreement with the prediction of the mixing-reaction model developed previously [1]. Furthermore, the results show clearly that in nitromethane the formation rate of nitronium ions from nitric acid is slower than the mixing rate and the rate of the electrophilic substitution proper. From the mixing-disguised selectivity curves for the nitrations of durene and prehnitene with nitronium hexafluorophosphate in nitromethane the ratio of the rate constants k2 for the second nitrations can be estimated to be 1:2. For the two aromatic compounds the k1/k2 ratios are ≥ 104. Finally it could also be shown that small impurities in the solvent (e.g. water) can influence strongly the selectivity curves, depending on the method used for mixing.

Notes: The oxidation of β-pinene with aqueous alkaline potassium periodate and catalytic amounts of potassium permanganate gave, in addition to the expected oxidation product nopinone, a β-ketol. The structure of the latter was shown to be 1-(2-hydroxyisopropyl)bicyclo[3.1.0]hexan-2-one. The formation of this anomalous side-product represents a new type of rearrangement of the pinane skeleton.

Notes: Phytochemistry of genus Gentiana XIII. Study of flavocic and xantonic compounds in the leaves of Gentiana campestris L. 2nd communication.By means of column chromatography on polyamide, we have isolated from the leaves of Gentiana campestris L. a new xanthone-O-glucoside, the 3,4-dimethoxy-5, 8-dihydroxy-xanthone-1-O-β-D-glucopyranoside (2) and its aglucone, the 3,4-dimethoxy-1,5,8-trihydroxy-xanthone (1). The C-glucosides mangiferin (3) and swertisin (4) have also been isolated and identified.

Notes: ESR.-spectra are reported for the radical anion and the radical cation of benzo[b]-biphenylene (III). Comparison of the proton coupling constants (aHμ) for III · ⊖ and III · ⊕ with π-spin populations (ϱμ), calculated by the McLachlan procedure, permits a lower limit of 0.77 to be set for the parameter κ = β′/β where β′ represents a reduced value of the HMO integral for the two essentially single bonds linking the benzene with the naphthalene π-system. The differences in the aHμ values for III · ⊖ and III · ⊕ are substantially larger than those generally found for the two corresponding radical ions of alternant, purely benzenoid hydrocarbons, but they closely parallel the analogous differences observed for the radical anion and the radical cation of biphenylene.

Notes: The radical anion and the radical cation of azuleno[1,2,3-cd]phenalene (III) have been investigated by ESR. spectroscopy, along with the radical anion of 2-phenylazulene (IV). Also studied has been the neutral radical obtained by one-electron reduction of cyclohepta[cd]phenalenium-cation (VI⊕). Assignment of the proton coupling constants for the radical ions III. ·⊖, III ·⊕ and IV·⊕, and the radical VI · is supported by comparison with the ESR. spectra of specifically deuteriated derivatives III-d5 ·⊖, III-d5 ·⊕, IV-d2 ·⊖ and VI-d1′. The experimental results are in full accord with qualitative topological arguments and predictions of HMO models. Whereas the radical anion III ·⊖ exhibits α-spin distribution similar to that of IV ·⊖the corresponding radical cation III ·⊕ and the neutral radical VI · are related in this respect to phenalenyl (V·). It is noteworthy that oxidation of III by conc. H2SO4 yields a paramagnetic species (IIIa ·⊕) which has a similar - but not an identical - structure as the radical cation III ·⊕ produced from III with AlCl3 in CH3NO2.

Notes: Radioactive deoxaphomin (1) which was obtained by feeding [4′-3H, U-14C]-L-phenylalanine to cultures of Phoma sp. (S298) was shown to be well incorporated into cytochalasin B (phomin) (2). The results demonstrate that 1 is an immediate biogenetic precursor of 2.

Notes: Transcyclopropanation during the Tetrabromination of a Tricyclic Ketone to 3 exo, 4 endo, 6exo-Tribromo-7-bromomethyl-1,5-dimethyl-tricyclo[3.2.1.02,7]octan-8-oneBromination of the tricyclic ketone 1 with an excess of bromine at low temperature gives in approximately 30% yield the highly crystalline tricyclic tetrabromide 2 (Scheme 1). The structure of 2 was established by NMR.- and especially X-ray-analysis (Fig.1).Treatment of 1 with 1 mol-equ. of bromine gives an unstable dibromide, to which the structure 3 was assigned on the basis of its NMR.-spectrum and its further bromination to 2 (Scheme 1). In the course of the tetrabromination of 1 the original cyclopropane ring is opened in the first step (1 → 3) and another cyclopropane ring is formed in the second step (3 → 2) (cf. Scheme 3).

Notes: The photochemical behaviour of the title compound (7) is described. The obtained results indicate the high reactivity of the enamidic Δ5 double bond.

Notes: Fluoroorganic Syntheses IV: 1-Fluoro-1-organyl-cyclopropanes and other Cyclopropane Derivatives by Addition of „Successor-Carbenes“Treatment of chlorodifluormethane or dichlorodifluoromethane with methyllithium in the presence of an olefin affords 1-fluoro-1-methylcyclopropanes in fair yields. Depending on the particular reaction conditions, 1,1-difluorocyclopropanes, 1,1-dimethylcyclopropanes and 1-chloro-1-methylcyclopropanes may be obtained as well. Butyllithium and phenyllithium give rise to analogous products.

Notes: He(I) and He(II) photoelectron spectra of benzo[b]selenophene and benzo[b]telluropheneThe photoelectron spectra of benzo[b]selenophene (2) and benzo[b]tellurophene (1) have been recorded with He(I) and He(II) radiation and been compared to those of benzo[b]thiophene (3), benzo[b]furan (4), indole (5) and indene (6). The first four bands are correlated with π-orbitals, of which the highest occupied one is strongly localized on the heteroatom in the case of 1. The results are in agreement with semi-empirical PPP-calculations.

Notes: Pterobiline and neopterobilines, reactivity and structuresPterobiline (biliverdine IX γ) and the two neopterobilines: phorcabiline and sarpedobiline, are the three main bile pigments found in Lepidopters. Studies on the reactivity of pterobiline (1) and phorcabiline esters are reported. Preparation of derivatives, in vitro transformation of pterobiline into phorcabiline, analysis of the pigments and their derivatives by field desorption mass spectrometry and Fourier transform NMR., lead to the structure 5 for the dimethyl ester of phorcabiline. By a similar reaction, biliverdine IX δ (15) affords the neobiliverdine IX δ (16). Possibility of an easy formation of new tetrapyrrolic compounds in the IX γ and IX δ series is thus reported for the first time.

Notes: Photochemical Generation and Reactions of Benzonitrile-benzylideThe low temperature irradiation of 2,3-diphenyl-2H-azirine (1) in DMBP-glass at -196° has been reinvestigated. It was possible to convert 1 nearly quantitatively into the dipolar species benzonitrile-benzylide (3, Φ3 = 0,78), which exhibits UV.-absorptions at 344 (∊ = 48000) and 244 nm (∊ = 28500) (Fig. 1, Tab. 1). Irradiation of 3 with 345 nm light at -196° resulted in almost complete reconversion to the azirine 1 (Φ = 0,15; Fig. 2). When the solution of 3 in the DMBP-glass was warmed up to about -160° a quantitative dimerization to 1,3,4, 6-tetraphenyl-2,5-diaza-1,3,5-hexatriene (8) occurred. This proves that 8 is not only formed by the indirect route 3 + 1 → 7 \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\longrightarrow }\limits^{hv} $\end{document} 11 → 8 known before (Scheme 1), but also by dimerization of 3 either by direct head to head coupling or via the intermediate e (p. 2675), followed by a fast thermal hydrogen transfer reaction.The occurrence of the dipolar intermediate 11 in the photochemical conversion of the bicyclic compound 7 to 8 could also be demonstrated by low temperature experiments: On irradiation at -196° 7 gave the cherry red dipolar intermediate 11 (λmax = 520 nm), which at -120° isomerizes to 8. It should be noted, that neither 7 nor 11 are formed by dimerization reactions of 3.Experiments carried out at room temperature demonstrate, that both processes for the formation of 8 may compete: Irradiation of a solution of 1 (DMBP, c = 8 × 10-4 to 5 × 10-3M) with 350 nm light of high intensity (which does not excite the bicyclic compound 7) leads to a relative high photostationary concentration of the dipolar species 3. Under these conditions the formation of 8 is due to dimerization of 3 (Φ8 = 0,19). With low light intensity only a very low stationary concentration of 3 can be obtained. Therefore the reaction of 3 with 1, leading to the bicyclic intermediate 7, becomes now predominant (Φ-1 = 1,55, which corresponds with the expected value of 2 × 0,8). Irradiation of 1 at -130° with 350 nm light of high intensity gives 8 with a quantum yield of 0,44. This is in agreement with the theoretical value Φ8 = 0,4 for an exclusive formation of 8 by dimerization of 3. The lower quantum yield for the formation of 8 at room temperature makes probable that under these conditions 3 not only dimerizes to 8, but also to another, so far unidentified dimer, e.g. 2,3,5,6-Tetraphenyl-2,5-dihydropyrazine.By flash photolysis of a solution of 1 (cyclohexane, c = 10-4M, 25°) the disappearance of 3 could directly be measured by UV.-spectroscopy: At relative high concentrations (c ≥ 10-7M) 3 disappeared according to a second order reaction with the rate constant k = 5 × 107M-1S-1. At lower concentrations (c ≤ 10-7M) the rate of disappearance of 3 follows first order kinetics. The rate constant of this pseudo first order reaction (3 + 1 → 7) has been determined to be 1 → 104M-1S-1.Using Padwa's table of relative rates for the cycloaddition of the dipolar species 3 to various dipolarophiles, including the azirine 1, an absolute rate constant of k ≈ 8 × 108M-1S-1 for the addition of 3 to the most active dipolarophile fumaronitrile could be estimated. In cyclohexane at room temperature, the diffusion controlled rate constant equals 6,6 × 109M-1S-1.In Table 1 the UV.-maxima of several nitrile-ylides, among them a purely aliphatic one, are given.

Notes: Adsorption potentials of simple molecules on various active carbons have been calculated directly from GSC. measurements, by using the procedure of Hansen et al. The model of slot-like micropores developed earlier, and based on a 3-9 adsorption potential, leads to consistent results. It reveals the existence of micropores having widths between 6.5 and 7.5 Å, in agreement with other methods.

Notes: Bei Verwendung von Rh-Alox-Katalysatoren lassen sich p-Aminophenyl-2-hydroxyäthyl-äther unter sorgfältig definierten Bedingungen ohne starke Hydrogenolyse zu cis-/trans-(4-Aminocyclohexyl)-(2-hydroxyäthyl)-äthern reduzieren; durch selektive Reduktion erhält man 4-Benzyl-cyclohexylamin aus 4-Benzylanilin sowie 1-(4-Aminocyclohexyl)-2-phenyl-äthan aus 1-(4-Aminophenyl)-2-phenyl-äthan.Rh- und Ru-Katalysatoren sind imstande, die bisher als nicht hydrierbar geltenden Methyl-, Amino- und Hydroxy-benzolsulfonsäuren quantitativ in die Methyl-, Amino- und Hydroxy-cyclohexansulfonsäuren überzuführen. Die Hydrierparameter werden ausführlich diskutiert.Wie sich aus 13C-NMR.-Daten herleiten lässt, entstehen bevorzugt die cis-Stereoisomeren. Die 4-Methyl-cyclohexansulfonsäure liegt bei Raumtemperatur zu 〉 90% in der Konformation mit axialer CH3- und äquatorialer SO3Θ-Gruppe vor (als Na-Salz in D2O gemessen).

Notes: Crystal Structure of a Dinuclear Peroxotitanium(IV)-Nitrilotriacetate ComplexThe structures of four peroxotitanium(IV) dipicolinates, with colours ranging from deep red to yellow orange, have been reported earlier, and a correlation between their colours and the variations of certain bond lengths has been proposed. This paper describes the pale yellow dinuclear peroxotitanium nitrilotriacetate complex Na4[Ti2O5(C6H6O6N)2]11 H2O. The monoclinic structure, space group B2/b, contains 25 independent non-hydrogen atoms and 17 hydrogen atoms. It has been determined from diffractometer data and refined to R = 3.2%. Titanium is again coordinated approximately pentagonal-bipyramidally. The μ-oxygen bridge occupies an axial position. The short (1.819 Å), nearly linear Ti-O-Ti bonds show double bond character. The titaniumperoxide bonds, however, are relatively long, thus confirming the rule proposed before: the more basic the axial ligands, the higher is the frequency of the absorption band, the longer are the Ti-peroxide bonds and the shorter are the axial distances. This is confirmed by electron density maps, which are to be discussed elsewhere in detail, showing bent Ti-peroxide bonds enclosing an angle of about 70° and a strong electron bridge on the μ-oxygen bond. Hydrogen bonding and the packing of the complexes is discussed.

Notes: New β-lactam antibiotics. Cephem derivatives with electron withdrawing substituents at position 3Oxidation of the 3-formyl-2-cephem compound 1 according to Corey [6] gave 2-cephem-3-carboxylic esters 4a, b, c (Scheme 1), which proved to be useful intermediates for the synthesis of cephalosporins bearing in position 3 a methoxycarbonyl group (10a, b, c, d / Scheme 2) or a carboxy group (20, 25, 30/Schemes 3, 4). The 3-formyl-3-cephem compounds 31a, b could be transformed into cyano- (33a) or methoxyiminomethyl- (36a, c, d) cephems (Scheme 5), which represent further examples of cephalosporins with electron withdrawing groups in position 3.

Notes: Es wird eine neue Synthese von β-Lactamen durch Umsatz von 4-Alkylazlactonen mit acyclischen Iminen beschrieben. Mit einem cyclischen Imin wird dagegen ein Imidazolin-Derivat erhalten.

Notes: How valid is the proof of existence of intermediates with pentacoordinated C-atoms in aliphatic SN2-reactions?Retention of configuration in the preparative conversion of cis-3-ethoxycyclobutylbrosylate (4) with sodium iodide and with lithium bromide in boiling acetone for 5 days to cis-3-ethoxycyclobutyliodide (6) and bromide (8), respectively, has been published by Ugi et al. to be the basis of a proof that species with pentacoordinated C-atoms exist sufficiently long during aliphatic SN2-reactions that they can undergo ligand reorganizations.It is now shown that the conditions used lead to a thermodynamic control, inasmuch as the cis- and trans-halides 6 and 7, as well as 8 and 9 isomerize to ∼2:1 equilibrium mixtures. Furthermore it is shown that the reaction of kinetic control occurs with inversion, inasmuch as the trans-: cis-halide ratio during the course of the reaction starts with high values and falls slowly to the equilibrium.Thus the nucleophilic substitutions on the examined four-membered ring system do not contravene previous experience with other aliphatic and alicyclic systems, so that the existence of pentacoordinated carbon species as intermediates in aliphatic SN2-reactions cannot be considered as proven.

Notes: The photo-oxidation of the title compound (1) is described. The isolated products are the result of a [2 + 2] oxygen addition to the olefinic double bond of the enamide.

Notes: Fluoroorganic Syntheses V. Preparation and Transformation of Chlorofluorocyclopropanes. - A Selective Approach to Fluoroallylic AlcoholsChlorofluorocarbene addition to unsaturated compounds is particularly convenient and efficient in a two-phase system. This method works satisfactorily even if the olefin carries base-sensitive substituents. The resultant chlorofluorocyclopropanes can be ring-opened by silver-salt assisted acetolysis affording 2-fluorallylacetates, which yield 2-fluorallylic alcohols upon saponification.

Notes: The ionisation energies and the HeI photoelectron spectra of the N-oxides of diazabenzenes are presented. The valence electronic structures of the N-oxides are discussed in view of the ionisation energies, and the profiles, of the bands. The interpreted data are compared to calculations which are in good agreement. The results are correlated to the physicochemical studies, and particularly to the electronic absorption spectroscopy, of the N-oxides. The assignment of the photoelectron spectra of the azabenzenes are considered with reference to the spectra of their N-oxides.

Notes: The synthesis and characterization of (±)-coralydine and (±)-O-methylcorytenchirine and their optical isomers are described.

Notes: S-Methylation of 6-S-benzyl-6-deoxy-1,2-O-isopropylidene-3-O-methyl-α-D-xylo-6-thiohexofuranos-5-ulose (1) gave the expected sulfonium salt 2 which on alcaline treatment yielded the stable sulfur ylide 3. This compound constitutes an useful synthetic intermediate in carbohydrate chemistry. On heating in 1,2-dimethoxyethane, it underwent a Stevens rearrangement which led to an extension of the carbon chain of the sugar and, reacted with Michael acceptors, it gave cyclopropanation reactions.

Notes: Acid-catalyzed rearrangement of 7-hydroxyroyleanone into a 20(10→9) abeo-abietane derivative and two phenalenonesShort treatment of either horminone (1b), taxoquinone (1a), 6,7-dehydroroyleanone (3) or 6β-hydroxyroyleanone (1c) with 80% H2SO4 at 0° leads to a mixture of rearranged products. Two of the structures, determined by X-ray-cristallography, were found to be (9R, 10R)-20(10→9)-abeo-12-hydroxy-5,7, 12-abietatriene-11,14-dione (4) and 9-isopropyl-2,2,5-trimethyl-8H-phenaleno[1,9-bc]furan-8-one (5), and the third compound, isolated in very small amounts, has been provisionally identified as 3-hydroxy-9-isopropyl-2,2,5-trimethyl-8H-phenaleno[1,9-bc]furan-8-one (6) from the spectroscopic data.

Notes: Intramolecular cyloadditions of binaphtyl compoundsThree new bridged ketones, 7,8 and 9, have been isolated in 44%, 3% and 19% yields respectively (Scheme 2) by heating 2,2′-bis-allyloxy-1,1′-binaphthyl (5) at 215° for 16 hours. These compounds could be epimerized about C(16) by bases, and in particular 9 yielded the new epimer 10. The structures of the alcohols obtained by reduction of the keto group are also given (Scheme 2). The constitution of all compounds was derived from spectroscopic data, chiefly from their 1H-NMR, spectra (tab. 2, 3 and fig. 1). The assignments were based on the observed long-range coupling constant between H(endo)-C(16) and H(endo)-C(5) in 7 and 10 and on the analysis of chemical shifts and coupling constants in both the ketones and their derivatives. Moreover, the structures of the compounds investigated have been proved by x-ray analysis of ketone 8 (chap. 3, fig. 2). The thermal conversion of binaphthylether 5 to the bridged ketones proceeds via an intramolecular Diels-Alder reaction, followed by Claisen rearrangement (Scheme 8). On heating, the bis-beta-methylallyl ether 20 yielded the ketone 21 and a small amount of the ether 23 (Schemes 5 and 7). Ether 23 and binaphthyl monoallyl ether 26 were converted thermally to the bridged ketones 31 (Scheme 7) and 27 (Scheme 6) respectively. In addition, 26 underwent an intramolecular ene-reaction to give the spiroketone 28 (Schemes 6 and 9). The structures of these compounds were also established, mainly by analysis of their 1H-NMR. spectra.

Notes: N-Isobutyl-11-(3, 4-methylenedioxyphenyl)-undeca-2,4,6-trans, trans, trans-trienoic amide (II) and N-isobutyl-11-(3,4-methylenedioxyphenyl)-undeca-2,8,10-trans, trans, trans-trienoic amide (III), two of the three possible structures of the alkaloid piperstachine, have been synthesized. Compound (III) has been found to be identical with piperstachine. The 1H- and 13C-NMR. spectra of the compound (II) are discussed.

Notes: Synthesis and Absolute Confifguration of the Enantiomers of Verapamil.Starting from the acids IV-(+) and IV-(-), a synthesis of the enantiomers I-(+) and I-(-) of the coronary vasodilator Verapamil is described and their absolute configuration determined through a chemical filiation with the acid XII-(S)-(+).

Notes: The He I photoelectron spectra of tetramethylcyclopentane-1,2,3-trione 1, 4,4,6,6-tetramethylcyclohexane-1,2,3-trione 2, bicyclo[1.2.3]octane-2,3,4-trione 3, bicyclo[2.2.3]nonane-2,3,4-trione 4 and anhydrous ninhydrine 5 are presented. The assignment of the first two bands is discussed using semiempirical calculations together with a qualitative band shape analysis. It is shown that the first two bands in 1 to 4 are due to the ionization of an electron from lone pair combinations of the 2p-oxygen orbitals.

Notes: The mass spectra of the three cyclopentane-1,2,3-triols, six cyclopentane-tetrols and four cyclopentane-pentols stereoisomers have been studied. Complex processes, especially regarding the H2O eliminations, were detected by extensive deuterium labelling.

Notes: Phenylpropionamides acylated in the ortho position with aralkanecarboxylic acids were cyclised to give, after reduction, 1-aralkyl-tetrahydro-2-benzazepines.

Notes: Structure of a Stable Dipolar Compound from 2,2-Dimethyl-3-dimethylamino-2H-azirine and Benzoylisothiocyanate.Benzoylisothiocyanate and 2,2-dimethyl-3-dimethylamino-2H-azirine (1) react to given the dipolar compound 4,4-dimethyl-2-thiazolin-5-dimethylimminium-2-benzcarboxamidate (2), whose structure has been proved by X-ray analysis. Compound 2, upon addition of water, yields the thiourea derivative 3, whereas by acid catalyzed hydrolysis the thiazolinone derivative 4 is formed. The dipolar structure 2 is also existent in organic solvents like dimethylsulfoxide or chloroform.

Notes: One the Reactivity of π-(η5-)-Cyclopentadienylpalladium-δ-(η1-)-allyl- and π-(η5-)-Cyclopentadienylpalladiumhalide Complexes; New ortho-Metallation Reactions of Trio-o-tolylphosphitTeil des Hauptvortrages von H. W. an der Jahrestagung der Chemical Society, York (U.K.), 7.-11.4.1975. 20.Mitt. der Reihe «Untersuchungen zur Reaktivität von Metall-π-Komplexen»; 19.Mitteilung siehe [1].(η5-C5H5)Pd(η3-2-ClC3H4) reacts with Lewis bases L[PPh3, P(OPh)3, P(O-p-Tol)3, P(O-o-Tol)3, CO] in a 1:1 molar ratio to give the η1-2-chloroallyl complexes 2a-2e. (η5-C5H5)-Pd(η1-2-ClC3H4)P(O-o-Tol)3 (2d) which is stable at room temperature has been isolated as a red oil. It represents the first well-characterized η1-allylpalladium derivative.2a-2d eliminate allene to form (η5-C5H5)PdClL (5a-5d). The tri-o-tolylphosphite complex 5d reacts with NaI to give (η5-C5H5)PdIP(O-o-Tol)3 (6) and on Al2O3 to give (η5-C5H5)Pd[P(OC6H3-o-Me)(OC6H4-o-Me)2] (7). Elimination of HCl leading to ortho-metallation of one of the six-membered rings of tri-o-tolylphosphite also occurs in the reaction of PdCl42- and P(O-o-Tol)3 to form Pd2Cl2[P(OC6H3-o-Me)(OC6 H4-o-Me)2]2 (9). This reacts with TlC5H5 to give 7. The preparation of Pd2Cl4[P(O-o-Tol)3]2 (8) and Pd2I2[P(OC6H3-o-Me)(OC6H4-o-Me)2]2 (10) is also reported.

Notes: On Reactions of oxygenated Cobalt(II) Complexes. V. Reactivity of diastereoisomeric μ-peroxo-μ-hydroxo-dicobalt(III) IonsThe kinetics of dissociation of μ-peroxo-μ-hydroxo-dicobalt(III) chelates have been reinvestigated using a stopped flow technique. The binuclear cations [(trien)Co(O2, OH) Co(trien)]3+, [(tren)Co(O2, OH)Co(tren)]3+ and [(en)2Co(O2, OH)Co(en)2]3+ dissociate on acidifying to Co2+ and the protonated ligand and up to 100% of the bound O2 is evolved. The dissociation is H+-catalyzed and first order in complex. The observed rate constants at pH 2 are in the range of 10-3 to 10-1 s-1 (20°). They depend not only on the nature of the ligand and on ligand configuration but also on the diastereoisomeric structure of the binuclear cation.In the case of trien there are 8 possible chemically different isomers. On oxygenation of Co(trien)2+ in dilute solution 3 of those isomers seem to be formed preferentially. Their rate constants are separated over a factor of 50. For [(en)2 Co(O2, OH)Co(en)2]3+ there exist a meso form and a chiral structure. On oxygenation of Co(en)22+ in dilute solution the meso form and the racemate are formed to about equal amounts. The racemate dissociates about 5 times slower. Of the 3 possible achiral isomers of [(tren)Co(O2, OH)Co(tren)]3+ one is formed stereoselectively by oxygenation in solution.

Notes: The 1H-decoupled 13C-NMR. spectra of 35 all-trans, 17 mono-cis vitamin A compounds (acetates, alcohols, aldehydes, acids and esters) and of one 11, 13-di-cis compound (11, 13-di-cis retinol) are reported. Included in this investigation are desmethyl-, desmethylethyl, and aryl-vitamin A analogues and others as well as 30 reference compounds of smaller molecular weight. Furthermore, the 13C-NMR. spectra of 23 β-apo- and other carotenoids were studied. A complete assignment of the signals of all 106 compounds to the specific carbon atoms was achieved by extensive application of lanthanide shift reagents, mainly Yb(dpm)3, by CW-offset and selective 1H-decoupling experiments, by comparison of the shifts of related compounds, and in three cases by utilization of specifically deuteriated compounds (11, 12-D2-retinol and retinyl acetate, 15, 15′-D2-β-carotene). The chemical shift differences between the cis- and trans-vitamin A compounds and the applicability of the shift reagents for the assignment of the 13C-NMR. spectra are discussed.

Notes: Enol derivatives in the chlorophyll series. 132-Desmethoxycarbonyl-173-desoxy-132,173-cyclochlorophyllide a-enol and a method for the introduction of magnesium into porphinoid ligands under mild conditionsMagnesium transfer from the iodo-magnesium salt of 3,5-di-t-butyl-4-hydroxy-toluene (BHT) into methyl pheophorbide a is a fast process in methylenechloride/ether solution at ambient temperature. This procedure for the introduction of magnesium into labile chlorin ligands has made possible the preparation of a crystalline 132, 173-cyclochlorophyllide a-enol. Concomitant use of the lithium salt of BHT facilitates the more critical insertion of magnesium into methyl bacteriopheophorbide a. The preparative success of these magnesium transfers depends crucially upon the solvent system used. Under conditions where the complexation of methyl pheophorbide a with iodo-magnesium-BHT is essentially complete within 2 minutes at 12° in methylenechloride/ether solution, strong inhibition of the magnesium transfer is observed by cosolvents such as pyridine, dimethylacetamide, dioxan or tetrahydrofuran.

Notes: Application of Ring Expansions for the Preparation of rac-Muscone and Exaltone®4,6-Undecamethylene-2-pyrone (8), prepared from 1-morpholino-cyclododec-1-ene (7) according to Hünig et al., was saponified and decarboxylated to a mixture of the 3-methyl-cyclotetradecenones 11, 12, 13 and 14, which was hydrogenated to 3-methyl-cyclotetradecanone (3). Similarly, 4,6-dodecamethylene-2-pyrone (16) was prepared from 1-morpholino-cyclotridec-1-ene (15) and ketene, saponified to a mixture of the 3-methyl-cyclopentadecenones 19, 20, 21 and 22 and the latter hydrogenated to rac-muscone (6).The ratios of the four regio- and stereoisomers in the above mentioned two mixtures of 3-methyl-cycloalkenones were derived from the 1H-NMR.-spectra.From the reactions of the enamines 7 and 15 were also isolated small amounts of 4,5-decamethylene- (9) and 4,5-undecamethylene-6-methyl-2-pyrone (17) respectively. Saponification and partial decarboxylation of 9 lead to (2-acetyl-cyclododec-1-enyl)-acetic acid (23) and methyl-(2-methyl-cyclododec-1-enyl)-ketone (24), the latter possessing an incense-like odor.The keton homologation method of Mock & Hartman (reaction of alkanones with diazoacetic ester in the presence of triethyl oxonium fluoroborate, followed by saponification and decarboxylation) was applied three times in succession, starting with cyclododecanone (1). This furnished, after the first stage, the cyclotridecanone (4) required for the above described synthesis of rac-muscone (6) and, after the third stage, cyclopentadecanone (5 = exaltone®).Application of this reaction to 2-methyl-cyclododecanone (28) resulted in a low yield of 2-methyl- (30) and 3-methyl-cyclotridecanone (31) in the ratio of 2:1.

Notes: Neue Cephalosporine, die in 3-Stellung eine Fluormethylgruppe aufweisen (9, 17/Schema 1), wurden ausgehend von 2b unter Verwendung von 2-Chlor-1,1,2-trifluor-triäthylamin als Fluorierungsmittel hergestellt. Mit Piperidin-schwefeltrifluorid erhielt man ferner aus 18 die 3-Difluormethyl-cephemverbindung 19 (Schema 2), die nach bekannten Methoden in antibakteriell wirksame Cephalosporine (20a, b) übergeführt wurde. 3-Fluor-cephemderivate, z.B. 23b, liessen sich ausgehend von entsprechenden 3-Hydroxy-cephemverbindungen, mit diesem Reagens jedoch nur in sehr geringer Ausbeute herstellen.

Notes: The Rǒle of Paliclavine in the Biosynthesis of Ergot AlkaloidsFeeding of [N-14CH3]-paliclavine to submersed cultures of Claviceps paspali Stevens et Hall and to surface cultures of the ergot fungus from Pennisetum typhoideum Rich. has shown that paliclavine is not involved in the biosynthesis of either the ergolene carboxylic acids or the tri- and tetra-cyclic clavines.

Notes: The structure elucidation of C-β-glucuronides of sulfinpyrazone (Anturan®) and phenylbutazone (Butazolidin®) by spectroscopic means is reported. These conjugates represent a novel type of drug metabolites.

Notes: Nous avons synthétisé une série de spiropyrannes benzoxathioliques par un processus en deux étapes: obtention de perchlorates styryliques en milieu acide par condensation simultanée de trois substrats intermédiaires, puis cyclisation en milieu basique. Un mécanisme est proposé.Ces spiropyrannes benzoxathioliques sont photochromes et nous avons étudié la cinétique de décoloration thermique ainsi que l'absorption visible de leurs photomérocyanines. Des observations comparables à celles enregistrées en série benzodithiolique nous ont amenés ici encore à envisager une structure de type quinonique pour la mérocyanine.

Notes: Tetrammine-copper(II)-tetraiodide Cu(NH3)4I4 crystallizes in the monoclinic space group C 2/m. The crystal structure has been determined from X-ray diffractometer data and refined to Rw = 2.2%. Four coplanar nitrogen atoms and two axial iodine atoms form an octahedral coordination around Cu(II) with a pronounced 4 + 2 tetragonal distortion. A connection of the Cu(II) atoms by linear, centrosymmetric I42- polyiodide ions results in infinite chains of [Cu(NH3)42+ I42-]-units. The central I-I-bond distance in I42- is 2.802(1) Å; a considerable amount of I-I bonding is indicated by the distance of 3.342(1) Å found for the terminal bonds. These intramolecular bond distances correspond to calculated I-I-bond orders of 0.80 and 0.43.

Notes: Template-Reactions II. Syntheses of tricyclic and tetracyclic metal complexes from aliphatic diamines and phenylazo-malondialdehyde-derivativesA template synthesis of metal complexes with 14- and 16-membered macrocycles 6 resp. 10 has been devised. These compounds are obtained in high yield by the condensation of aliphatic 1,2-or 1,3-diamines with phenylazo-malon-dialdehydes in the presence of divalent metal ions such as Cu(II) and Ni(II). This is the first reported one-step synthesis of tetraaza-annulenes with aliphatic diamines. The formation of the intermediate tricyclic complexes 5 and 9, obtained either by a template or a nontemplate synthesis, is also described. Ring closure with diamines leads again to 6 and 10 or to asymmetric tetraaza-macrocyclic systems such as 7 or 11.

Notes: ESR.-spectra are reported for the radical anion I · Θ of 2,7-diazapyrene (I), along with those for the radical cations I(2H) · ⊕ and I(2 CH3) · ⊕ of 2,7-dihydro-2,7-diazapyrene and its 2,7-dimethyl-derivative, respectively. In contrast to the analogous radical ions of 4,4′-bipyridyl (II) and other previously studied diazaaromatic compounds, there is a striking change in the 14N and proton coupling constants on going from the radical anion I · Θ to the radical cations I(2H) · ⊕ and I(2 CH3) · ⊕. This change can be rationalized in terms of the HMO model of the pyrene π-system. A reversal in the energy sequence of the lowest antibonding orbitals is predicted upon an increase in the absolute value of the Coulomb integral for the azasubstituted π-centres, such an increase simulating the enhanced electronegativity of the azanitrogen atoms 2 and 7 on protonation.

Notes: Addition-elimination reactions from germanium heterocycles I. Germadioxolanes (X=Y=O)The reactivity of 2-germa-1,3-dioxolanes is studied with unsaturated compounds such as carbonyl compounds (aldehydes and ketones) or heterocumulenes (PhNCO, PhNCS). The formation of mono- and di-insertion derivatives is observed. The structure of these adducts is established and their decomposition process, at atmospheric pressure or at high pressure, is precised.The mechanism of these addition-elimination reactions is established from 4,5-disubstitued germadioxolanes. The reaction takes place under steric control. The consecutive elimination reaction proceeds by a mechanism of intramolecular nucleophilic substitution.

Notes: Benzo[b]thiophene-2,3-diones (1) react with Grignard reagents to yield 2,3-dihydroxy-2,3-diaryl(aralkyl)benzo[b]-thiophenes (2). The latter compounds yield 3,3-diaryl(aralkyl)-benzo[b]thiophene-2-ones (3) by pinacolone rearrangement. Treatment of 3 by hot ethanolic sodium hydroxide solution yields the corresponding carboxylic acids by hydrolytic heteroring opening.

Notes: The title compound is recommended as a photosensitizer for excitation by visible light of up to 500 nm due to the following properties: high triplet yield, low singlet-triplet splitting (ET = 55 kcal/mol), low photochemical reactivity.

Notes: The highly stereospecific reduction of (1R)-3-endo-aminobornan-2-one (2) to [1R]-3-endo-amino-2-endom-bornanol (1) is described. This reaction is achieved by using alkylaluminumdichlorides, a new group of reducing agents for the reduction of the ketone 2 to the secondary alcohol 1Diesc Reduktion ist Gegenstand van Patcntanmeldungen, z. B. [l].

Notes: ζ-Oxo-α, β-enones react with lithium dimethylcuprate to give cyclic aldols such as hydroxydecalone 1 and hydroxyspiro[4.5]decanone 2 in a regio- and stereospecific manner. This new reaction, a combination of conjugate methyl addition to α, β-enones with directed intramolecular aldolisation, is suggested to proceed via either enoate anions, such as 8 and 11, or radical anions, such as 9 → 10 and 12 → 13, as intermediates.

Notes: The synthesis of the N-quaternary aminoalcohol 6 is described. Analogous to the aminoalcohols 1 and 2, 6 on treatment with alkali undergoes fission of the substituent at C(1) as a carbonyl compound, with formation of a N, N-dimethyl-1,2,3,4-tetrahydroisoquinolinium ion, which is further degraded to the corresponding o-vinyl-benzylamine (Scheme1). - As a by-product of a Bischler-Napieralski ring closure, we observed chlorination of an aromatic ring (yielding 19).

Notes: Coleons C, D, I, I′, obtained from a Madagascan Plectranthus sp. nov.. Interconversion of cis- and trans-A/B-6,7-Diketoditerpenes.Fairly large amounts of Coleons C and D, as well as Coleons I and I′ (3-O-formyl derivative of Coleon I) can bc isolated from the orange glands of an unclassified North Madagascan Plectranthus sp. A reversible transformation of cis- and trans-A/B-6,7-dioxo-abietane via its diosphenol has been achieved for the first time. CD.-Spectra of these compounds are presented. Hydrogenolysis of Coleon D leads to 6β,16-dihydroxy-royleanone.

Notes: Horminone, taxoquinone and other royleanones, obtained from two Abyssinian Plectranthus species (Labiatae).From the coloured glands on the leaves of two botanically unclassified Plectranthus sp. from Abyssinia, a series of royleanones has been isolated, namely royleanone (1) and 6,7-dehydroroyleanone (2) from one species, and 6,7-dehydroroyleanone, horminone (3), taxoquinone (4), 6β, 7α-dihydroxyroyleanone (5), 7α-acetoxy-6β-hydroxyroyleanone (6) and 7-oxoroyleanone (7) respectively, from the other.

Notes: It has been found that the properties of the lanthanide and actinide ions and their complexes vary linearly with the L-values (the total angular momentum). Usually plots resembling a four segmented «inclined W» are obtained for the whole series, where the data are available. Although some deviation from a symmetrically «inclined W» plot occured in a few cases, the linearity is maintained within the four segments. It is suggested that in future, for correlating the properties of the lanthanide and actinide series, the L-values rather than the atomic number (Z) or number of the f-electrons, should be used.

Notes: Die Strukturen von zwei säurekatalysierten Umlagerungsprodukten von Taxochinon (1) wurden kristallographisch bestimmt: Die eine Verbindung stellte sich als ein 20 (10 → 9) abeo-Abietan (2) heraus, die andere als ein achirales Phenalenon (3). Die Abietanverbindung, C20H26O3, kristallisiert in der Raumgruppe P212121 mit 4 Molekeln in der Zelle und wurde mit 879 signifikanten Reflexionen bis R = 0,032 verfeinort. Die Phenalenonvervindung, C20H22O2, KRISTALLISIERT IN DER rAUMGRUPPE p21/c mit 12 Molekeln in der Zelle und wurde mit 1823 signifikanten Reflektionen bis R = 0,058 verfeinert.

Notes: Structure Determination of Azafrin Methyl Ester 5-O-Monomethyl Ether by 13C-NMR.-Specta.The structure of the monomethyl ether (2) of azafrin methyl ester (1) was determined by a partial analysis of the 13C-NMR.-spectra. Assignments of quaternary carbon atoms and methyl groups in the cyclohexane ring were achieved using vicinal 13C-, 1H-spin coupling. Substituent effects on methyl and methylene carbon atoms in 2 are discussed with respect to the conformation of the methoxy group. The spectra prove C(5)—OH as the site of methylation. Therefore C(5)—OH is less hindered than C(6)—OH.

Notes: Eine thermische (a) und eine reduktive (b) Methode zur Herstellung von Mikanez-Estern wird beschrieben. Bei der ersten gelang der Nachweis des monomeren Vorläufers, 1,3-Butadien-2-carboxylester. (a)trans/cis-Gemische von Methyl resp. Äthyl 2-Brom-1-methylcyclopropancarboxylat (14/15 resp. 16/17), mit Tri-n-butylzinnhydrid aus den entsprechenden 2,2-Dibrom-1-methylcyclopropancarboxylaten 12 resp. 13 hergestellt, wurden bei 480°/1,7 Torr pyrolysiert. Die bei -78° daraus abgefangenen Kondensate bestanden aus den 1,3-Butadien-2-carboxylaten 5 und 6, im Falle des Äthylesters 6 durch seine 1H-NMR.-Signale charakterisiert und als Addukt (19) mit 4-Phenyl-1,2,4-triazolin-3,5-dion (18) abgefangen (55%). Beim Erwärmen der Kondensate dimerisierten die Dienester 5 resp. 6, so dass sich Dimethyl resp. Diäthyl Mikanezat (9 resp. 10) isolieren liess (67 resp. 100%).(b)Behandlung von Methyl 2(E)-2-Methyl-2-butenoat (20) mit 2 Äquivalenten N-Bromsuccinimid gab (25%) Methyl 2(Z)-4-Brom-2-brommethyl-2-butenoat (21). (Mit 3 Äquivalenten entstand ein Stereomerengemisch 2(Z)- und 2(E)-4,4-Dibrom-2-brommethyl-2-butenoat (22 und 23)). Reduktion des Dibromesters 21 mit Zink in Tetrahydrofuran, Methanol oder Eisessig ergab (50%) Dimethyl Mikanezat (9). Von einer Iodolaktonisierung der aus 9 durch Verseifung hergestellten Mikanezsäure (8) erhielt man 4-Iodo-7-oxo-1-vinyl-6-oxabicyclo[3.2.1]octan-4endo-carbonsäure (24), dessen Bildungsleichtigkeit und IR.-Bande bei 1780 cm eine unabhängige Bestätigung dafür liefert, dass Mikanezsäure (8) durch Kopf-zu-Kopf-Diels-Alder-Dimerisierung von 1,3-Butadien-2-carbonsäure (4) entsteht.Aus Methyl (E)-2-Methyl-2-pentenoat (25) wurde auf gleiche Weise, d.h. über Dibromierung zu 27 und Reduktion mit Zink in Äther, Dimethyl 3,2′-Dimethylmikanezat (29) gewonnen. Die Multiplizität des 1H-NMR.-Signals von H—C(3) in 29 bestätigt, wiederum unabhängig, dass die Dimerisierung des Dienesters (in diesem Fall 28) in Kopf-zu-Kopf-Diels-Alder-Weise stattfindet.

Notes: A method is described in which the ‘allowed’ course of a reaction is determined by means of an analysis - within the symmetry point group common to reactants and products - of their molecular orbitals and of the distortions that occur along the reaction path connecting them. The procedure, and its relation to and advantages over conventional correlation methods, is illustrated with a few very well known reactions: Cyclization of hexatriene, the ‘photochemical Diels-Alder reaction’ and the stepwise and concerted [2+2]-cycloadditions.

Notes: Photochemistry of α,β-epoxyketones: γ-H-abstraction versus epoxyketone-rearrangement.The photochemical behaviour of conformationally mobile α,β-epoxyketones that could undergo competing reactions has been studied. The UV.-irradiation of 5 yields the stereoisomeric cyclobutanols 9 and 10 as well as the fragmentation product 11. Irradiation of 6 gives only the cyclobutanols 12 and 13, whereas 4 and 8 in inert solvents yielded only intractable gums. The non-occurrence of the typical isomerization of α,β-epoxylketones to the corresponding β-diketones is attributed to steric factors.

Notes: The catalytic hydrogenation of aminalsThe catalytic hydrogenation of aminals, the bis-N-analogs of acetals, was investigated. 3-(γ-Aminopropyl)-piperidines are formed by the hydrogenolytic splitting of the C-N-bond of decahydro-1, 8-naphthyridines. The reaction is stereospecifically influenced by the catalyst used. Non cyclic aminals are hydrogenated in the same manner. The mass and NMR. Spectra of 3-(γ-aminopropyl)-piperidines are discussed.

Notes: The electron transfer spectra of adducts of the title metal halides with a series of ligands (nitriles, dialkylchalcogenides, phosphoryl and thiophosphoryl ligands and phosphines) have been studied. The effect of halogen substitution on the halogen metal transitions is discussed by comparing the spectra of the adducts with those of the hexahalometalates. The origin of the two ligand-metal transitions observed in most adducts is discussed, and the splitting of the metal d levels in these almost octahedral adducts is estimated. For each metal halide, the series of adducts with dialkyl chalcogenides show a linear relationship of slope one between the ligand ionisation potential and the ligand-metal charge transfer energy. The ligand optical electronegativities have been estimated.

Notes: Further theoretical calculations have been carried out for the adsorption potentials of Ar on the (011) face of rhombic sulfur, and for Xe and SF6 on the (011) and (111) faces. By using the same sites for the three molecules and pair-potentials of the Lennard-Jones type, specific scaling factors were found. These are constant within 5-10%, for each adsorbate, and therefore the distribution curves of the adsorption potentials of simple molecules on crystalline sulfur are related in a simple way. The influence of the size of the molecule and the local geometry of the surface is also discussed.

Notes: On Reactions of oxygenated Cobalt(II) Chelates. VI. Preparation of diastereoisomeric tetrakis(ethylenediamine)-μ-peroxo-μl-hydroxo-dicobalt(III) PerchloratesOxygenation of Co(en)22+ leads to a mixture of two isomeric forms of [(en)2Co(O2, OH)-Co(en)2] (ClO4)3 · H2O from which the less soluble meso form can be readily crystallized. Further crystallization from the mother liquor yields the racemate ΔΔ/ΔΔ. The pure racemate may be obtained by either of the following methods: (a) By ligand exchange starting from mono bridged [(NH3)5CoO2Co(NH3)5] (NO3)4 or from doubly bridged [(SCN) (NH3)3Co(O2, OH)Co(NH3)3(SCN)] SCN · 2H2O. (b) By reaction of cis-[Co(en)2(OH2)2]3+ with H2O2. Reaction (b) proceeds via an intermediate cis-[Co(en)2(OOH) (OH2)] (ClO4)2 · H2O which at higher pH reacts with [Co(en)2(OH) (OH2)]2+ to yield the desired doubly bridged ΔΔ/ΔΔ tetrakis(ethylenediamine)-μ-peroxo-μ-hydroxodikobalt(III)-perchlorate.

Notes: The electrostatic potential (EP.) for aceheptylene (I) is calculated using ab-initio wavefunctions. In addition, the EP. around I is approximated by a monopole expression, using wavefunctions from various semiempirical procedures as a basis. It is found that the previously noted discrepancy between the thoretical prediction of differential nuclophilicity of the individual unsaturated C-atoms in 3,5,8,10-tetramethyl-aceheptylene(II) and the experimental results of protonation is removed, if instead of local atomic charges, the EP. around II, approximated by that of I is considered.

Notes: New β-lactam antibiotics. Functionalisation of the cephem 3-position with sulfur or nitrogen bearing substituentsThe tosylate sulfoxides or mesylates derived from the 3-hydroxy-ceph-3-em esters 1a, b reacted with thiols to give 3-thioethers which were converted into the microbiologically active acids 7a, c, 8a, c 9c, and 13c by known procedures. The 3-methylsulfonyl-derivative 17c was prepared from 6b. The synthesis of the 3-acylamino-ceph-3-em-4-carboxylic acids 23c and 24c is reported.

Notes: A Stereospecific, Light- and Acid Catalyzed Allylic Rearrangement; Syntsesis of PaliclavineThe synthesis of paliclavine, a recently isolated metabolite of strain of Claviceps paspali STEVENS et HALL, was achieved by an acid- and photo-sensitized stereoselective allylic rearrangement of chanoclavine-I and isochanoclavine-I. In a second approach N-methyl-chanoclavine-I was converted to N-methyl-paliclavine by the same method, subsequent N-demethylation led to paliclavine. The chemical prerequisites and the mechanism of the reaction are discussed.

Notes: A simple ‘three-component-reaction’ between halo- or alkylthio-ketenes, Schiff bases and sulfur dioxide, yielding 4-oxo-1,3-thiazolidine-1,1-dioxides 4 in one step, is presented.

Notes: Cyclization Reactions of Quinonylmethane Dyes and Analogous Merocyanines. 2. Communication: Dihydro-oxo-naphto-phenazines. Correlation of Solubility and Substitution. Isolation and Characterization of an Intermediate CompoundAn intermediate compound of the cyclization reaction of 2-chloro-3-(1-cyclohexyl-3-methyl-1,2-dihydroquinoxalin-2-ylidenmethyl)-naphthoquinone was isolated and characterized by spectroscopic methods. 6-Chloro-8-cyclohexyl-5,8-dihydronaphtho[1,2-b]phenazinone was obtained as the final product of this reaction. Several more dihydronaphtho[1,2-b]phenazinone dyes were synthesized. The relationship of substitution and solubility of the dyes is discussed. The visible and 1H-NMR. and some mass spectra of the dyes are given.

Notes: Cyclization Reactions of Quinonylmethane Dyes and Analogous Merocyanines. 3. Communication. Quinoid Derivatives of the Anellated Tetrahydro-quinoxalino-quinoxaline. Cyclization Following 1,7-Hydrogene-Shift?The title compounds were obtained by proton catalyzed cyclization of the corresponding 2-(1-alkyl-3-methyl-1,2-dihydroquinoxalin-2-ylidenmethyl)-1,4-naphtho- and 1,4-anthraquinones. The visible and 1H-NMR.- and some mass spectra of the dyes are given. Mechanistic aspects of the new-type cyclization reaction are discussed.

Notes: Nous avons étudié la transformation réversible de spiropyrannes benzodithioliques photochromes en mérocyanines: les spectres d'absorption de celles-ci et leurs cinétiques de décoloration thermique sont suivis en utilisant un spectrophotomètre à enregistrement rapide couplé à un appareil de photolyse-éclair. Les nombreuses inversions constatées par rapport aux résultats cinétiques obtenus en série benzothiazolinique pour des composés identiquement substitués, associées à des considérations sur les spectres visibles des photomérocyanines et à des effets de polarité de solvant, nous amènent à envisager pour les mérocyanines benzodithioliques une structure de type quinonique alors qu'en série benzothiazolinique une structure de type dipolaire a été mise en évidence.

Notes: Stereoselectivity of Diastereogenic CC-Linking Reactions II. A Carbene/Carbenoid-Cascade and «Hypermechanisms»In a systematic study four pairs of dihalocarbene precursors were treated with methyllithium in the presence of 2-methyl-2-pentene. Each pair was made up of a tetrahalomethane and a trihalomethane, namely CCl4 vs. CHCl3, CCl3F vs. CHCl2F, CCl2F2 vs. CHClF2 and CClF3 vs. CHF3. Since all the tetrahalomethanes reacted exclusively by chlorine/lithium exchange and all the trihalomethanes by hydrogen/lithium exchange, each pair gave rise (at least formally) to an identical ‘carbenoid’. Two different carbenoids may always undergo elimination of LiCl or LiF and thus collapse generating the same carbene.A comparison of the product composition (ratios of straight-forward cycloaddition vs. consecutive substitution reactions, ratios of diastereoisomers) reveals more or less marked, but always significant discrepancies in the outcome of ‘carbene-convergent’ as well as ‘carbenoid-convergent’ reactions.

Notes: The HeI photoelectron spectra of mono-, di-, and triacetylenes are presented. In these compounds the two-centre π-orbitals of the ethynyl groups conjugate with the π-orbitals of double bonds or benzene moieties, or with the Walsh orbitals of three-membered ring systems. Assuming the validity of Koopmans' approximation, the observed energies of the radical cation states reached by electron ejection from π-orbitals can be rationalized in terms of a simple LCBO-MO model in those cases, where the molecule is planar. The corresponding numerical results for the ionization energies are in excellent agreement with experiment, if the three parameters of the model are properly calibrated. In contrast, the bands assigned to ejection from in plane π-orbitals are shifted to lower energies by ca. 0.5 eV with respect to the expectation values derived from the above model, due to ‘through-bond’ interaction with lower lying σ-orbitals.Extensive σ/π mixing occurs in the non planar compounds for all orbitals. The assignments of the spectra of diethynylmethane, 1,4-hexadiyne, 1,2-diethynylethane and of cis- and trans-diethynylcyclopropane are backed by semiempirical SCF calculations. The spectra of the cis and trans isomers of diethynylethyleneoxide and diethynylethylenesulfide are discussed by comparison with the corresponding hydrocarbons and with oxirane and thiirane respectively.Finally, the following topics are considered in detail: (a) The effect of spin orbit coupling on the spectrum of 1-iodo-1-butyne-3-ene; (b) the effect of the essentially free internal rotation in divinylacetylene on the band shapes of its photoelectron spectrum and (c) the relationship between the conjugative properties of ethylenic π-orbitals and of the Walsh-orbitals of cyclopropane.

Notes: Irradiation (280-350 nm light) of a benzene solution of 3-phenyl-2H-azirines 1a-e in the presence of carboxylate esters, whose carbonyl groups are activated by electron withdrawing groups situated in the acyl or alkyl moiety, produces 5-alkoxy-3-oxazolines (Tab. 1 and 4, Scheme 2) isolated in 18-82% yield. These heterocycles undoubtedly originate by regiospecific addition of the ester carbonyl group to the azirine-derived benzonitrile-methylide ‘dipole’ (Scheme 1). The 5-(2,′ 2′, 2′-trifluoroethoxy)-3-oxazolines, derived from 2′, 2′, 2′-trifluoroethyl carboxylic esters, on treatment with methanolic hydrogen chloride at low concentration, are smoothly transformed into the corresponding 5-methoxy-3-oxazolines (e.g. 16 → 17, Tab. 5). Utilizing this process, various hitherto relatively unknown 9. 5-alkoxy-3-oxazolines become accessible.The constitution of the adducts is based essentially on spectral data. The structure of trans-5-methoxy-2,4-diphenyl-5-trifluoromethyl-3-oxazoline (trans-14), the addition product of methyl trifluoroacetate and the benzonitrile-benzylide from 2,3-diphenyl-2H-azirine (1d), was determined by X-ray crystallography (Section 5).Benzonitrile-isopropylide (22), resulting from the photochemical transformation of 2,2-dimethyl-3-phenyl-2H-azirine (1a), also reacts with S-methyl thiobenzoate to give 2,2-dimethyl-5-methylthio-4,5-diphenyl-3-oxazoline (26). Ethyl cyanoacetate protonates predominantly the dipolar species derived from 1a at the nitrile C-atom and yields after work-up ethyl α-cyano-cinnamate (29) and ethyl isopropylidene-cyanoacetate (30) (Scheme 4).The relative rate of addition (krel) of benzonitrile-isopropylide (22) to methyl α-haloacetates and dimethyl oxalate was determined by competition experiments (Section 6). Log krel correlated satisfactorily (r = 0.97) with the pKa of the acide derived from the ester reactant: log krel = - 1.72 pKa + 2.58 or with Taft's substituent constants σ*: log krel = 2.06 σ* - 4.11 [krel(methyl dichloroacetate) = 1; Section 7.1].On the basis of the results obtained, the mode of reaction of the so-called benzonitrile-methylide ‘dipole’ is discussed and a model for the transition state of addition of ester-carbonyl groups is proposed that accounts for the observed regiospecifity and steroselectivity.

Notes: Reaktion von Triasterandion (1) mit N-Bromsuccinimid ergab 44% 9-Brom-triasterandion (5), neben wenig 9,9-Dibrom-triasterandion (6). Substitution des Bromatoms in 5 durch eine Acetoxygruppe ergab 74% 9-Acetoxy-triasterandion (10). Umesterung mit Natriumäthylat und Oxydation des rohen Hydroxy-diketons 9 führte zu Triasterantrion (2). Versuche, Triasteranon (11) mit N-Bromsuccinimid in 3,5-Dibrom-triasteranon (7) umzuwandeln, waren ohne Erfolg.

Notes: Derivatives of benzyl 2-[1-(benzyloxy)formamido]-2-deoxy-α-D-glucopyranoside with various protecting groups at C(3) (benzoyl, benzyl and N-phenylcarbamoyl) and C(6) (benzoyl, benzylsulfonyl, N-phenylcarbamoyl and tosyl) have been synthesized as starting materials for disaccharides. The C(4) and C(6) hydroxyl groups of the amino sugar were initially blocked by an acetal group. After introduction of the protecting group at C(3), the acetal group was removed by acid hydrolysis, and the C(6) hydroxyl group was selectively acylated or sulfonylated. The 3,6-di-O-benzoate has also been prepared by dimolar benzoylation of the amino sugar, whereby the 4,6-isomer was obtained as a by-product.

Notes: Utilization of sodium [1-14C]-, [2-14C]-, and [1,2-13C]-acetates, [1-14C]-, [1-13C]-, or [2-14C]-propionates, [1-14C]-or [2-14C]-malonates, of [1-14C]- or of [1-14C]-myristic acid, or of [1-14C]- and [1-14C]-palmitic acid in the biosynthesis of cytochalasin D (1) by Zygosporium masonii was determined by degradation studies or by carbon magnetic resonance spectroscopy. The precursors were incorporated primarily via the acetate-malonate pathway to generate 1 from nine intact acetate units, eight of which are coupled in a head to tail fashion to form the C16-polyketide moiety.

Notes: A total synthesis of betalaine pigments (6) is described. The key intermediate is betalamic acid in the form of its dimethyl ester semicarbazone (9), which was transformed with L-proline (16) into indicaxanthine dimenthl ester (5), with L-cyclodopa methul ester (17) into betanidine trimethyl ester (3) and by hydrolysis of the latter into betanidine (2).

Notes: Photochemistry of 1,1-dimethyl-4-phenyl-and 1-Methyl-1-phenyl-1,2-dihydronaphthalene; evidence for a photochemical, sigmatropic [1,7]H-shift.Irradiation of 1,1-dimethyl-4-phenyl-1,2-dihydronaphthalene (11) and 1-methyl-1-phenyl-1,2-dihydronaphthalene (8) in pentane were investigated at -112° to -118°, using a mercury high pressure lamp. The [1,5]-hydrogen-shift products 13 and 17, respectively, the [1,7]-hydrogen-shift products 15 and 10, respectively and the photochemical Diels-Alder products 14 and 18, respectively, were obtained, presumably via the ω-vinyl-o-quinodimethane intermediates 12 and 9 (Schema 3).Irradiation of the 1,2-dihydronaphthalene 11 at -181° to -183° in a 2,2-dimethylbutane/pentane matrix, gave rise to an UV.-maximum at 402 nm which is assigned to the o-quinodimethane derivative 12. After warming the solution around -130° or to room temperature, a product mixture was obtained, which mainly consist of the [1,7]-hydrogen-shift product 15 accompanied by the [1,5]-hydrogen-shift products 13 and 16 and the photochemical Diels-Alder product 14 (Table 1). When the o-quinodimethane intermediate 12 was irradiated with 406 nm-light, the longwavelength absorption completely disappeared. This solution, after warmingup, yielded mainly the [1,5]-hydrogen-shift products 13 and 16 together with the bicyclic compound 14 and surprisingly a small amount of the [1,7]-hydrogen-shift product 15 (Table 1).Similar experiments were carried out with the 1,2-dihydronaphthalene 8. The results clearly indicate that irradiation of the o-quinodimethane 9 at -180° to -185° with 406 nm-light caused [1,5]- and [1,7]-hydrogen shifts in a ratio of approximately 1:1 (Table 2).From the experiments described above it follows, that the phenyl-substituted α-methyl-ω-vinyl-o-quinodimethanes 12 and 9 undergo upon irradiation with light of λ 〉 400 nm, besides photochemical Diels-Alder reactions, also [1,5]- and [1,7]- hydrogen shifts.It is remarkable that the thermal [1,7]-hydrogen-shifts of the o-quinodimethanes 12 and 9 occur readily around -130°, whilst a temperature of -70° is needed to promote [1,7]-hydrogen-shifts in the non-phenylated o-quinodimethanes of the type 2 (Schema 1). The phenyl group in ω- or α-position may enter into conjugation with the π-system in the helcal transition state of the [1,7]-hydrogen shift, but not in the reactants 12 and 9.

Notes: Two [4.4.3]propellane lactones 3 and 8 were prepared by employing the chloronitrone reaction. The intermediate propellanes 9 and 12 were also isolated in pure form.

Notes: The molar volumes of mixtures of perdeuteriated and protiated heptane have been measured between -10° and 40° and expressed as a second order polynomial of the weight fraction. The difference in molar volumes of about 0.4 ml/mol decreases with temperature. The possibility of using the density measurement to determine the degree of deuteriation of mixtures of partially deuteriated heptanes was examined. The percent deuteriation calculated by this method deviates systematically from the true values.

Notes: Three new alkaloids designated as cyclostachine A (2), cyclostachine B (7) and cyclopiperstachine (10) have been isolated from Piper trichostachyon C. DC. Their structures have been derived on the basis of spectral and degradative studies and confirmed by synthesis. The 1H- and 13C-NMR. spectra of these compounds are discussed.

Notes: Enol derivatives in the chlorophyll series. Preparation of 132,173-cyclopheophorbide enols132,173-Cyclopheophorbide enols have been prepared as model systems for studying the effect of ring E enolization upon the properties of chlorophyll derivatives.

Notes: The NMR. spectrum of guanidinium ion 1 is studied in anisotropic liquid crystalline nematic solution. Assuming an HNH-angle of 120°, the distance ratio NH/NC = 0.784 is obtained, from which using NC = 1.330 Å (from X-ray data) NH = 1.043 Å results. An upper bound for the free energy of activation for bond rotation of ΔG+ ≤ 13 kcal/mol is deduced. The bondrotational mobility of 1 is also investigated using the MINDO/3-SCF-procedure. The results obtained for the three conceivable consecutive activation energies for bond-rotation indicate that the observed bond-rotational mobility of 1 does not involve cooperative two- or three-bond rotations. The ‘conjugative stabilization’ of 1 has been estimated to be of the order of 24-26 kcal/mol.

Notes: Specific covalent attachment of adrenocorticotropin and angiotensin II derivatives to polymeric matrices for use in affinity chromatographyThe purpose of this investigation was to prepare polymer-supported forms of adrenocorticotropin and angiotensin II with unique points of covalent attachment and presumably low rates of hormone detachment, making them potentially useful for affinity chromatography. Conventional chemical synthesis provided the peptides cysteinyl-ACTH (5-24) ([4-cysteine]-adrenocorticotropin-(4-24)-heneikosipeptide) and cysteinyl-angiotensin II amide ([I-Nα-cysteinyl-asparagine,5-valine]-angiotensin II). Strategies were devised to bind these hormone derivatives either in the protected form to polyacrylamide or in the deprotected form to sepharose beads. The obtained high degree of matrix substitution suggests a general applicability of these methods.

Notes: Phthalimido-nitrene IITeil I, siehe [1]. . cis- and trans-2,3-Dimethyl-1-phthalimido-aziridine. Synthesis and Solvolytic Reactions Teilweise vorgetragen in der Versammlung der Schweizerischen Chemischen Gesellschaft in St. Gallen am 4. Oktober 1969 und in vorläufiger Form veröffentlicht [2].The addition of phthalimido-nitrene (2), generated by lead tetraacetate oxidation of N-amino-phthalimide (1), to cis- and trans-2-butene gave stereospecifically cis- 3 and trans-2,3-dimethyl-1-phthalimido-aziridine 4 respectively. Acetolysis converted the cis-aziridine 3 slowly and the trans-aziridine 4 rapidly, again stereospecifically, to threo-7 and erythro-O-acetoxy-3-phthalimidoamino-2-butanol (8) respectively. The velocity relation of the two acetolyses is considered to be due to a difference in steric release on the way to the transition state of a SN2-type reaction. Acid-catalysis converted 7 to threo-11 and 8 to erythro-3-(N-acetyl-N-phthalimido-amino)-2-butanol (12). The equilibria in this acetyl migration between oxygen and nitrogen (threo-pair 7:11 = 65:35; erythro-pair 8:12 = 91:9) are rationalized on steric grounds.The hydrolyses of 3 and 4 were equally stereospecific, leading to threo-9 and erythro-3-phthalimidoamino-2-butanol (10) respectively. These two compounds 9 and 10 were also available by reacting phthalimide (23) respectively with threo-17 and erythro-3-hydrazino-2-butanol (18) which in turn were prepared by hydrazinolysis of cis-13 and trans-2,3-dimethyloxirane (14) respectively. A N-phthaloyl to N,N′-phthaloyl rearrangement (possibly base catalyzed) was observed, which converted 9 and 10 to threo-19 and erythro-(N,N′-phthaloyl)-3-hydrazino-2-butanol (20) respectively.It is of interest that in the compounds discussed above the NMR.-coupling (in deuteriotrichloromethane) between H--C(2) and H—C(3) is larger (J = 6-9 Hz) in the threo-series than in the erythro-series (J = 2-3 Hz). This shows a depopulation of the conformers 21a and 22a with anti-periplanar arrangement of the hetero substituents, rationalizable by intramolecular hydrogen bonds in the conformers 21b ⇄ 21c and 22b ⇄ 22c. This is confirmed by the observation that the stereomeric pairs 19/20 and 9/10 show equal coupling between H—C(2) and H—C(3) (J = 8/8 and 6.6/7 respectively) when the NMR.-spectra were measured in hexadeuterio-dimethylsulfoxide, a solvent which can compete with intramolecular hydrogen bonding.An attempt is made to rationalize why the NMR.-chemical shifts in deuteriotrichloromethane of H—C(2) and H—C(3) in the threo-series lie at higher fields than those in the erythro-series, the exception again being the 19/20, pair, measured in hexadeuterio-dimethylsulfoxide.

Notes: The influence of mass diffusion on substrate and positional selectivities is discussed. A simple model is developed which allows a description and simulation of the coupling of the mass diffusion with the chemical reaction during the mixing process of two reactant solutions. For competitive, consecutive reactions and competitive, parallel reactions the general behaviour and the dependence of the product selectivity on diffusion effects is demonstrated.

Notes: Hormone-Receptor Interactions. Synthesses of α-Melanotropin and of Informational Sequences thereof with the Aid of Alcali-Labile Protecting Groups.The aim of this investigation was to prepare α-melanotropin and partial sequences thereof for biological investigations in as pure a state as possible. Classical synthesis in solution was chosen as the general approach, because it allows for extensive purification and identification of all intermediates, thus warranting the chemical identity of the products (in contrast to the solidphase methods). The scheme of protection was as follows: for the Nα-amino groups mostly t-butoxycarbonyl (BOC-), sometimes benzyloxycarbonyl (Z-), for the N∊-amino group of lysine-(11) 2-(methylsulfonyl)-ethoxycarbonyl (MSOC-), and for the carboxylic acid group of C-terminal glycine-(10) 2-(4-tolyl-sulfonyl)-ethoxy (-OTSE). This provides for facile and mild selective deprotection of either the α-amino groups by acidolysis or of the ∊-amino group (α-carboxyl group) by β-elimination in alcali. A slight molar excess of 0.12N HCl in HCOOH proved to be the method of choice for removing BOC-; MSOC- is stable in acid (even for 30 min in liquid HF) and easily removed in a few minutes by 0.05--0.1N Ba(OH)2; -OTSE is removed similarly. Condensation of amino-acid and peptide derivatives (formation of the peptide link) was performed using active esters (-ONP; -OSU), dicyclohexyl-carbodiimide (DCCI) with or without 1-hydroxy-benzotriazole (HOBT), or carboxylic acid azides wherever histidine was the carboxylic component.More than 50 compounds are described. Those characterized by arabic numerals served to prove that α-MSH contains two message sequences that are able to trigger melanocyte response: one in the central region -His-Phe-Arg-Trp-, the other in the C-terminal portion -Gly-Lys-Pro-Val · NH2 of the molecule [3].