Reactions of 5-alpha-hydroxy steroids. VII. The westphalen rearrangement of some 3-beta-substituted-6-beta-acetoxy-5-alpha-hydroxy cholestanes.
Abstract Product analyses and kinetic studies of the reactions of 3β-substituted-6β-acetoxy-5α-hydroxy cholestanes with H 2 SO 4 -Ac 2 O-AcOH reveal a marked dependence of the reactions upon the nature of the 3β-substituent.
Acid catalysed reactions of 5α-hydroxy-steroids—V : Some reactions of substituted cholest-4-enes
Abstract The four epimeric 3,6-diacetoxycholest-4-enes undergo equilibration at C-3, but not at C-6, in sulphuric acid (or HBF 4 )-acetic acid-acetic anhydride solutions. The equilibrium ratios of epimers have been estimated. Under similar reactions conditions various 6β-substituted-3β-acetoxycholest-4- enes suffer acetolysis at C-6 with retention of configuration.
Synthesis of 2,4-dideoxy-.beta.-D-erythro-hexopyranosyl nucleosides
The synthesis of 1-(2,4-dideoxy-β-D-erythro-hexopyranosyl)thymine (12) 1 was accomplished using two different synthetic routes. It was obtained starting either from 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose or from tri-O-acetyl-D-glucal. The other modified nucleosides, with either a cytosine, guanine, or adenine moiety, were synthesized using the second reaction scheme. Deoxygenation reactions were accomplished with the (2,4-dichlorophenoxy)thiocarbonyl derivatives generated in situ