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Notes: Summary 1. Axenic cultures of Bumilleriopsis were cultivated in mineral medium under continuous illumination and diluted every two days. The growth has been calculated to be 0.50 log10/day units at the optimum temperature of 23 to 24° C. 2. In liquid medium one cell normally divides into 2n daughter cells (=aplanospores). Under our culture conditions generally 8 and 16 daughter cells are produced by one Bumilleriopsis cell within 48 h. 3. Bumilleriopsis filiformis is the first Xanthophycean species to be synchronized. Light-dark changes induce some synchronization, but a high percentage of simultaneous division and rapid completion of a cell division burst is brought about most effectively by cycles composed of strong light/dim light/temperature changes (LS-T). With the most effective combination tested, i.e. 33 h of white 15000 lux light followed by 15 h of white 3000 lux (dim) light at temperatures of 24° in the first and 19° C in the second light phase (=33:15 h/15000:3000 lux/24:19° C), 96% of the cells divide synchronously. The burst occurs in such a manner that, on an average, 50% of the cells have divided 38 h after the start of the cycle. These synchronizing conditions were maintained up to 30 cycles without interruption (=continuous synchronization). 4. Cell wall formation is observed (by staining mother cells with methylene blue) 1 to 2 h before the cells divide completely and their daughter cells are released.

Notes: The mechanism of the catalysis of the reversible (propargyl ester)/(allenyl ester) rearrangement (10 ⇄ 11) by silver(I) ions was investigated, using optically active and diastereoisomeric esters as well as 14C- and 18O-labelling. In order to work with crystalline materials, mainly p-nitrobenzoates (10, 11: R4 = p—O2N—C6H4) were used. In some cases the rearrangement 10 ⇄ 11 was studied using acetates (R4 = CH3). The alkyl substituents R1, R2, R3, were widely varied (cf. Tables 1, 2). The solvents in which the rearrangements were performed were in most cases dry chlorobenzene and 96% aqueous dioxane. Silver tetrafluoroborate, the benzene complex of the latter, and silver trifluoroacetate (in chlorobenzene) as well as silver nitrate (in aqueous dioxane) served as catalysts. The amounts of the silver catalysts used varied between 0,5 and 10 mol-%; reaction temperatures applied were in the range 35-95°, The results obtained are as follows: 1The rate-determining step of the (propargyl ester)/(allenyl ester) rearrangement (10 ⇄ 11) occurs in a silver(I) complex with the substrates (10, 11), which is formed in a pre-equilibrium. This follows from kinetic experiments (cf. Fig. 6, 7, 8, 10) and the fact that the rate of rearrangement (of 10a) is strongly decreased when cyclohexene is added (cf. Fig. 9). In solvents which are known to form complexes with silver(I) ions the rate of rearrangement (of 10a)is much slower than in solvents with similar dielectric constants but with small capacity for complex formation with silver(I) ions (cf. Table 4). Taking into account what is known about silver(I)-alkene and -alkyne complexes (cf. [18]), it is obvious that the (propargyl ester)/(allenyl ester) rearrangement occurs in a π-complex of the silver(I) ion with the triple bond in the propargyl ester or one of the two C,C double bonds in the allenyl ester, respectively.2The shift of the carboxyl moiety in the reversible rearrangement 10 ⇄ 11 occurs intramolecularly. p-Nitrobenzoic acid-[carboxyl-14C] is not incorporated during the rearrangement, neither in the reactant 10 nor in the product 11 and vice versa. A crossing experiment gave no mixed products (cf. Scheme 2, p. 882).3An internal ion pair can be excluded for the rearrangement 10 ⇄ 11 because the 18O-carbonyl label in the reactant is found exclusively in the alkoxy part of the product (cf. Scheme 3, p. 886, and Table 9). Thus, the rearrangement 10 ⇄ 11 occurs with inversion of the carboxyl moiety.4The rearrangement of optically active propargyl esters (10g, 10i) leads to completely racemic allenyl esters (11g, 11i). However, rearrangement of erythro- and threo-10j-[carbonyl-18O] (Scheme 3) shows that the stereospecifically formed allenyl esters erythro- and threo-11j-[18O]-epimerize rapidly in the presence of silver(I) ions. This epimerization is twice and forty times, respectively, as fast as the rearrangement of the corresponding propargyl esters (cf. Fig. 1-5). During epimerization or racemization the 18O-label is not randomized (cf. also Scheme 4, p. 898).5The equilibrium of the rearrangement 10 ⇄ 11 depends on the bulkiness of the substituents R1, R2, R3 and of the carboxyl moiety (cf. Table 2).Taking into account these facts (points 1-5), the reversible (propargyl ester)/(allenyl ester) rearrangement promoted by silver(I) ions can be described as a [3s, 3s]-sigmatropic reaction occurring in a silver(I)-π-complex with the C,C triple bond in 10 and a C,C double bond in 11. It is suggested that complex formation in 10 and 11 occurs with the π-bond which is not involved in the quasicyclic (containing six orbitals and six electrons) transition state of the rearrangement (Fig. 11). Thus, the rearrangement is of a type which has recently been called a charge-induced sigmatropic reaction (cf. [26]). Therefore, in our case, the catalysis by silver(I) ions is of a different type from that of transformations of strained cyclic molecules promoted by silver(I) ions (cf. [14] [16] [27]-[31]).Side reactions. Whereas the rearrangement of propargyl esters 10 in presence of silver tetra- fluoroborate in chlorobenzene or silver nitrate in aqueous dioxane leads to the corresponding allenyl esters 11, the rearrangement of 10 with silver trifluoroacetate, especially in the presence of trifluoroacetic acid, results in the formation of the dienol esters 12 and 13, which clearly are derived from 11 (see Scheme 1, p. 881). As shown by the rearrangement of 11 in the presence of p-nitrobenzoic acid-[carboxyl-14C], 12 and 13 arise in part from a not isolated di-p-nitrobenzoate (cf. Scheme 6, p. 905), since radioactivity is found in 12 and 13.

Notes: From the leaves of the Apocynaceae Pleiocarpa talbotii WERNHAM three new indole alkaloids were isolated and identified as 3,4,5,6-tetradehydrotalbotine (2), 5,6-dehydrotalbotine (3) and deformyl talbotinic acid methylester (4). From the stem bark of the same plant normacusine B (tombozine) was isolated.

Notes: (±)-Oncinotin (19) is synthesized through the crucial intermediates 11 and 15. By comparison of the synthetic product with natural (-)-oncinotin, it is found that the latter contains an isomeric substance, represented by structure 20.

Notes: Structure 1 has been elucidated for chaenorhine, an alkaloid isolated from Chaenorhinum organifolium (Scrophulariaceae). The key derivative for the structural elucidation is 13,14,21,22-tetrahydro-21,22-seco-chaenorhine (21). 21 gave upon hydrolysis spermine and 4-hydroxydihydrocinnamic acid characterized as the tetraacetyl derivative 18 and as the dimethyl derivative respectively.

Notes: 3-Phenylisocumarine was isolated for the first time from natural source (leaves of Homalium laurifolium JACQ.).

Notes: The structure of ester of 2-hydroxy-4-methoxy-6-methylbenzoic acid with 6-acetoxy-7-hydroxy-7-methyl-3-propenyl-3,4,5,6,7,8-hexahydro-1H-benzo[e]pyran-8-one (1) is assigned to wortmin, a new member of the sclerotiorin group of metabolites, produced by Penicillium wortmanni Klöcker.

Notes: The mass spectral behaviour of the difunctional alkane N-acetyl-4-phenyl-butylamine (3) was investigated. The main fragmentation of compound 3 is caused by the interaction on the two functional groups, which could be shown by comparison of the corresponding monofunctional compounds n-butylbenzene (4) and N-acetyl-n-butylamine (5). On the bases of high resolution data, the analyses of metastable transitions and the comparison of the spectra of some homologs and deuterated analogs of 3 the structures and their genesis of the main fragment ions were deducted.

Notes: Some different substituted N-methyl-β,β′-diphenyl-diethylamines (I) were investigated mass spectrometrically. The main fragmentations and their genesis are summarized in Scheme 2. The molecular ion generates the major fragmentions a (m/e 148) and b (m/e (147 + X)); c (m/e 105) is formed from a and d (m/e (104+X)) from b by further decomposition. The logarithms of the ratios of the relative ion intensities a/b, c/a and d/b were correlated according to the Hammett equation with different substituent constants. The following correlation coefficients (at 20ev) were found: r = 0,98 (σ+), r = 0,63 (σ) and r = 0,96 (σ) respectively. On the basis of the above Hammett correlations, the value of this kind of investigation for the elucidation of mass spectral fragmentation mechanisms is discussed.

Notes: The mass spectral behaviour of tetraacetyl spermine (2) has been investigated. The fragmentation reactions are characterized by the neighbouring group participation of the amide nitrogen atoms. Only a few reactions can be explained by usual pathways (α-cleavage, onium reactions). Most of the fragment-ions are formed by neighbouring group participation: 1[M-COCH3]+-Ion.2Breakdown of one of the two 1,3-diaminopropan moieties: m/e 242, 256, 268. This type of fragmentation is characteristic for all acetylated 1,3-diaminopropan-derivatives e.g. triacetylspermidine.3Expulsion of a neutral amine: m/e 169.4SNi-type reactions, by which cyclic ions are formed: m/e 100.