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  • 1
    Electronic Resource
    Electronic Resource
    (±)-6-Benzyl-3,3-dimethylmorpholine-2,5-dione and its 5-monothio and 2,5-dithio derivatives (2001)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. 634-637 
    Details
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The morpholine ring of the title dione, C13H15NO3, shows a boat conformation that is distorted towards a twist-boat, with the boat ends being the two Csp3 atoms of the ring. The benzyl substituent is in the favoured `exo' position. In the monothione derivative, (±)-6-benzyl-3,3-dimethyl-5-thioxomorpholin-2-one, C13H15NO2S, this ring has a much flatter conformation that is midway between a boat and an envelope, with the dimethyl end being almost planar. The orientation of the benzyl group is `endo'. The dithione derivative, (±)-6-benzyl-3,3-dimethylmorpholine-2,5-dithione, C13H15NOS2, has two symmetry-independent molecules, which show different puckering of the morpholine ring. One molecule has a flattened envelope conformation distorted towards a screw-boat, while the conformation in the other molecule is similar to that in the monothione derivative. Intermolecular hydrogen bonds link the molecules in the three compounds, respectively, into centrosymmetric dimers, infinite chains, and dimers made up of one of each of the symmetry-independent molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108270101003195
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  • 2
    Electronic Resource
    Electronic Resource
    Dispiro[fluorene-9,5′-[1,2,3,4]tetrathiane-6′,9′′-fluorene] (2001)
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. 764-766 
    Details
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The tetrathiane ring of the title compound, C26H16S4, has a chair conformation and the molecule has approximate C2 symmetry. Each of the two fluorene ring systems is virtually planar, with the ring planes intersecting at an angle of 67.58 (5)°. This novel compound has been formed as a side product from the treatment of 9H-fluorene-9-thione with methyl N-[(benzylidene)phenyl]glycinate in the presence of LiBr and 1,6-diazabicyclo[5.4.0]undecane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108270101005248
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  • 3
    Electronic Resource
    Electronic Resource
    The Reaction of 3-(Dimethylamino)-2H-azirines with 2,3-Pyridinedicarboximide (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 1319-1327 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of 2,2-dialkyl-3-(dimethylamino)-2H-azirines 1a and 1b with 2,3-pyridinedicarboximide (4) in MeCN or DMF at room temperature yielded two regioisomeric tricyclic 1:1 adducts, the azacyclols 11/12 and 16/17, respectively (Schemes 3 and 4). The structure of 12 was established by X-ray crystallography. Methanolysis of 11/12 and 16/17 led to mixtures of methyl [4, 4-dialkyl-5-(dimethylamino)-4H-imidazol-2-yl] pyridine carboxylates 13/14 and 18/19, respectively. The structure of compound 14 is closely related to that of the powerful herbicide 9 (Scheme 9), i.e. the described reactions offer a new synthetic approach to this class of compounds. A mechanistic interpretation for the formation of regioisomeric 1:1 adducts as well as methyl (imidazol-2-yl) pyridine carboxylates is depicted in Scheme 5.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710542
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Oxidation von 1,2-Thiazolen: Ein einfacher Zugang zu 1,2-Thiazol-3(2H)-on-1,1-dioxidenHerrn Prof. Dr. Siegfried Hauptmann zum 60. Geburtstag gewidmet (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 1059-1070 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidation of 1,2-Thiazoles; A Convenient Approach to 1,2-Thiazol-3(2H)-one 1,1-DioxidesThe 1,2-thiazoles obtained from 3-chloroalk-2-enals and ammonium thiocyanate (7 → 9, Scheme 1) are easily transformed to 1,2-thiazol-3(2H)-one 1,1-dioxidcs 10 on treatment with H2O2 in AcOH at 80°. Hydrogenation of 10 in AcOH yields the corresponding saturated 1,2-thiazolidin-3-one 1,1-dioxides 16 (Scheme 3). Cycloalka[c]-1,2-thiazoles 18 are prepared from 2-[(thiocyanato)methyliden]cycloalkan-1-ones and ammonia (Scheme 4). Surprisingly, oxidation of 18a with H2O2 in AcOH yields the tricyclic oxaziridine 19.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740515
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  • 5
    Electronic Resource
    Electronic Resource
    Synthese von (Methylthio)penam-Derivaten durch Keten-Addition an 4,5-Dihydro-5-(methylthio)-1,3-thiazole (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1424-1434 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of (Methylthio)penam Derivatives via Keten Addition onto 4,5-Dihydro-5-(methylthio)-1,3-thiazolesThe 4,5-dihydro-5-(methylthio)-2-phenyl-1,3-thiazoles 3a and 3b, easily prepared from the corresponding 1,3-thiazol-5(4H)-thiones and MeLi, react with dichloroacetyl chloride (5a) and acidoacetyl chloride (5b) in the presence of Et3N to give (methylthio)penam derivatives 6 (Table 1). The reaction mechanism is either a [2 + 2] cycloaddition of in situ generated ketene or a two-step reaction (Scheme 2). The structure of 6f has been confirmed by X-ray crystallography (Fig. 2). The relative configuration of 6a-e follow from comparison of their 1H-NMR spectra with those of 6f (Fig. 1). The 6-azidopenams 6d and 6f have been reduced to aminopenams 8a and 8b, respectively. Acylation of 8a with phenacetyl chloride yields 9 (Scheme 4).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690615
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  • 6
    Electronic Resource
    Electronic Resource
    Regioselektive 1,3-dipolare Cycloadditionen von Thiocarbonyl-yliden mit 1,3-Thiazol-5(4H)-thionen (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 1386-1398 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Regioselective 1,3-Dipolar Cycloadditions of Thiocarbonyl Ylides with 1,3-Thiazole-5(4H)-thionesThe thiocarbonyl ylides 13 and 1,3-thiazol-5(4H)-thiones 1 undergo a smooth reaction to yield spirocyclic 1,3-dithiolanes 14-16 (Schemes 4-6). The 1,3-dipolar cycloadditions occur in a regioselective manner, but the orientation of the thiobcnzophenone-S-methylide (13b) differs from that of the cycloalkane thione-S-methylides 13a and 13c. Whereas the 1,3-cycloadduct with 13b is formed in accordance with frontier-orbital considerations, the inverse orientation in the reactions with 13a and 13c most likely is the result of steric hindrance in the transition state. The thiocarbonyl ylides have been prepared in situ from the corresponding 2,5-dihydro-1,3,4-thiadiazoles 12. The more stable aliphatic precursors 12a and 12c undergo decomposition at 50°, the unstable 12b at -30°.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740703
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  • 7
    Electronic Resource
    Electronic Resource
    1,3-Oxathiolan-Synthese: Spirocyclische 1,3-Oxathiolane aus der Lewis-Säure-katalysierten Umsetzung von cyclischen Trithiocarbonaten und OxiranenHerrn Professor Dr. C. H. Eugster zum 70. Geburtstag gewidmet (1991)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 74 (1991), S. 1500-1510 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Oxathiolanc Synthesis: Spirocyclic 1,3-Oxathiolanes from the Lewis-Acid-Catalyzed Reaction of Cyclic Trithiocarbonates and OxiranesThe cyclic trithiocarbonates 1.3-dithiolane-2-thione (4) and 1,3-dithiole-2-thione (9) in 1,2-dichloroethane and MeCN, respectively, react with alkyl- and phenyl-substituted oxiranes 2 in the presence of Lewis acids to give 1-oxa-4,6,9-trithiaspiro[4.4]nonanes 5 and 6 (Scheme 2) and 1-oxa-4,6,9-trithiaspiro[4.4]non-7-enes 10 and 11 (Scheme 3), respectively. The reactions proceed regioselectively yielding 2-alkyl (5, 10) and 3-phenyl derivatives (6, 11) as the main products. From the reaction of 4 and 2-phenyloxirane (2e) with TiCl4, 2-phenyl-1,4,6,9-tetrathia-spiro[4.4]nonane (7) is isolated as a minor product. The molecular structures of 5a, 6e, and 7 are established by X-ray crystallography.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19910740714
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  • 8
    Electronic Resource
    Electronic Resource
    Carbophile Additionen von Organocupraten mit 1,3-Thiazol-5(4H)-thionen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1837-1843 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbophilic Additions of Organocuprates and 1,3-Thiazole-5(4H)-thionesOrganocuprates and 1,3-thiazole-5(4H)-thiones 1 react in THF at 0° via carbophilic addition onto the C—S bond to give 4,5-dihydro-1,3-thiazole-5-thiols 3 (Scheme 3). This observation is in marked contrast to the previously described reaction of organolithium compounds and 1, which undergo a thiophilic addition onto the exocyclic S-atom. As an exception, treatment of the 1,3-thiazole-5(4H)-thione 1a with tert-butyl cuprate leads to 7a (Scheme 3).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19860690809
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  • 9
    Electronic Resource
    Electronic Resource
    Struktur und Mechanismus in der organischen Chemie im Spiegel von Helvetica Chimica ActaWir behandeln die Zeit von 1918 bis ca. 1968, also die ersten 50 Jahre, und gehen auf spätere Ereignisse nur ein, sofern sie in direktem Zusammenhang mit früheren stehen. (1992)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 75 (1992), S. 359-437 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 96 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19920750202
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  • 10
    Electronic Resource
    Electronic Resource
    Reaktion von 2-Diazopropan mit 1,3-Thiazol-5(4H)-thionen (1992)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 75 (1992), S. 1825-1833 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of 2-Diazopropane and 1,3-Thiazole-5(4H)-thionesAt 0°, 1,3-thiazoles 1 and 2-diazopropane in pentane or MeOH undergo a smooth 1,3-dipolar cycloaddition to give spirocyclic 2,4-dihydro-1,3,4-thiadiazoles 6 (Scheme 3). Elimination of N2 occurs already at 20°, yielding spirocyclic thüranes 7. At room temperature, the latter decompose slowly to give 4,5-dihydro-5-isopropylidene-1,3-thiazoles 8. The desulfurization 7 → 8 can be accelerated by heating or by addition of trimethyl phosphite. The intermediate of the N2 elimination of 6 is a thiocarbonyl ylide D which can be trapped with the reactive dipolarophiles thiobenzophenone and fumarodinitrile (Scheme 4). In the absence of these trapping reagents, D undergoes ring closure to thüranes 7. The cycloaddition of D and a second molecule of 1, the so-called Schönberg reaction, is not observed.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19920750608
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