摘要:

AbstractTwo crystallographically independent molecules with differing half‐chair conformations of ring A were found in the analysis of Org OD 14. These results are compared with published X‐ray structure analyses andWestheimer‐type calculations of related steroids. It is concluded that the energy differences between the half‐chair and envelope conformations of ring A of 3‐oxo 5(10)‐unsaturated steroid

ISSN:0165-0513    

DOI:10.1002/recl.19841030501

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractGas‐phase thermolysis oftert‐butyl hydroperoxide1, ≤1% m in nitrogen (pyrex reactor, atm. pressure, 200‐300°C), gives methane and acetone as the main products. The homolytic mechanism involves O‐O bond dissociation (eqn. 1) and induced decomposition of1by hydroxyl and methyl radicals (eqn. 3).In the presence of a ≥50 fold excess of toluene, reaction (3) is suppressed,•OH and part of the•Me radicals abstracting hydrogen from toluene (eqn. 9).Values fork3bandk9b(abstraction by•Me) are derived and discussed.Arrheniusparameters fork1, logA/s−1= 15.3,EA= 41.4 kcal/mol, are in agreement with the thermochemistry and with the results of the VLPP s

ISSN:0165-0513    

DOI:10.1002/recl.19841030502

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractUpon irradiation (λ>525 nm), xanthenethione2oand thioxanthenethione2sreact in a non‐regiospecific manner with the triple bond of the acetylenes6a(Ph‐C≡C‐SCH3) and6b[(2‐thienyl)–C≡C‐SCH3] to produce in each case the two possible (2 + 2)‐cycloaddition products, which were isolated as thietes or α,β‐unsaturated thioxo compounds. In a solution of each of these reaction products, spectroscopic results confirmed the occurrence of the equilibrium thiete ⇋ α, β‐unsaturated thioxo compound. With acetylene6c(t‐Bu‐C≡C‐SCH3), the photochemically excited thiones2oand2sgave, in each case, only the (2 + 2)‐cycloaddition product8. In solution these thietes8do not equilibrate with the corresponding α, β‐unsaturated thiones. Surprisingly, no products could be isolated or detected after irradiation of thiobenzoph

ISSN:0165-0513    

DOI:10.1002/recl.19841030503

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractPhosphorylation of 2′‐O‐acetyl‐3′‐(trifluoroacetamido)‐3′‐deoxy‐N6‐benzoyladenosine with 1,1′‐[(4‐morpholinyl)phosphorylidenedi‐oxy]bis‐1H‐benzotriazole gives a fully protected intermediate. The latter, after removal of the benzotriazolyl group from the 5′‐phosphotriester function, can be converted by the addition of pyrophosphoric acid, followed by the removal of

ISSN:0165-0513    

DOI:10.1002/recl.19841030504

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractCationic cyclization of 2‐[7‐(3‐methoxyphenyl)‐(E)‐3‐heptenyl]‐3‐methyl‐2‐cyclopentenol (7) gave mainly tetracyclic products via Ar1‐6 and/or Ar2‐7 participation. The major product, 3‐methoxy‐17‐methyl‐B‐homo‐1,3,5(10),13(17)‐gonatetraene (9), was converted in two steps intoB‐homoestrone methyl ether20. High‐resolution1H NMR spectra indicated that the seven‐membered ring in9occurs mainly in a boat‐like conformation whereas in its 1‐methoxy isomer8it occurs in an unsymmetrical twist‐boat conformation. In20, theB‐ring p

ISSN:0165-0513    

DOI:10.1002/recl.19841030505

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractIn basic alcohol, 7‐(methoxycarbonyl)‐1,3,5‐cycloheptatriene (7b) forms its 2‐, 3‐ and 1‐isomers (viz.2b,3band1b) in successive reactions. All isomers show specific hydrogen exchange in CD3ONa/CD3OD. For 3‐ and 1‐(methoxycarbonyl)‐1,3,5‐cycloheptatriene vinylic hydrogen atoms are exchanged rather than the

ISSN:0165-0513    

DOI:10.1002/recl.19841030506

出版商:WILEY‐VCH Verlag    

年代:1984

数据来源: WILEY