Preparation of 17-Ketosteroids from Enol Acetates of 20-Ketosteroids^1a

Synthesis of Bradyrhizose Oligosaccharides Relevant to the Bradyrhizobium O‐Antigen

“…Basic conditions such as Ac 2 O/DMAP led to either no reaction or overreaction (to form the 3‐ O ‐acetoacetyl derivative 6 ) . Fortunately, treatment of 5β / 5α with Ac 2 O and a catalytic amount of CSA at RT afforded the desired acetates 7β (51 %) and 7α (46 %), which were easily separable. The β‐anomer was employed to prepare the glycosyl donor.…”

The Merck Bile Acid Cortisone Process: The Next-to-Last Word

“…Gallagher had utilized chromatographically purified enol acetates, which were formed by slow distillation of an acetic anhydride solution of substrate containing p -toluenesulfonic acid . Their benzene solutions could be epoxidized with 2 M perbenzoic acid in an hour.…”

Drug Latentiation

“…Treatment of cholesteryl pyruvate with isopropenyl acetate, using p-toluenesulfonic or sulfuric acid as catalyst (30), failed to give the corresponding enol acetate (VII). Slow distillation of a solution of the pyruvate in acetic anhydride (p-toluenesulfonic acid catalyst) gave the enol acetate (VII) II N-NHCeHa(N0z)z 0-C-CHs II 0 VII in low yield (31). The product crystallized poorly and attempted chromatographic puriiication on alumina gave cholesterol as the major product.…”