Synthesis of steroidal D-ring fused pyrazolines: Study of regiochemistry of addition
摘要:
The addition of diphenylnitrilimine and C-o-chlorodiphenylnitrilimine to 3 beta-hydroxyandrost-5,16-diene (3b) produced a 1/1 ratio of regioisomeric, 1,3-diaryl-2-pyrazolines (6a, 7a and 6b, 7b), whereas the addition of N-o-chlorodiphenylnitrilimine gave a 5/1 ratio in favor of the [17 alpha,16 alpha-d] regioisomer (7c). To further delineate the factors governing the regiochemistry of addition of diphenylnitrilimines to steroid 16-enes, additions were carried out on 16-acetyl-5 alpha-androst-16-ene (5b) and 1-acetylcyclopentene (10).
(+)-5α-雄甾烯-14,16-二烯(2),(-)-冰片酚[2,3 - b ]环戊-1,3-二烯(3),(+)-报道了2,3-二亚甲基冰片烷(4b),(-)-冰片[2,3 - c ] -2,5-二苯基环戊-2,4-二烯-1-酮(9a)以及相关化合物。在这些相对刚性的,基本上为平面的类固醇共轭二烯体系中,取代基的手性效应起着重要作用。
Hydroxy-steroids. Part IV. The preparation and spectra of steroid olefins
作者:G. M. L. Cragg、C. W. Davey、D. N. Hall、G. D. Meakins、E. E. Richards、T. L. Whateley
DOI:10.1039/j39660001266
日期:——
Convenient preparations have been developed for a series of steroidal mono-olefins free from oxygenated substituents: this Series includes representatives of all but one of the possible endocyclic olefins. The infrared, nuclear magnetic resonance, and ultraviolet spectra of the compounds were examined with particular attention to the relative power and scope of the different techniques in structural
Diols are efficient co-catalysts in guanidine catalysedcondensation of ketones and aldehydes. According to quantum chemical calculations the acceleration effect can be explained by the formation of complexes of carbonyl compounds and diols held together by double H-bonding. The base/diol mixture can be separated from the product and recycled by reversible CO2 capture and release.