Synthesis of the 14α- and 16α-epimers of bufotalin acetate and 16-deacetylcinobufagin

Autor:	Cecil R. Smith, Masuo Inoue, Yoshiaki Kamano, David Weisleder, Machiko Tozawa, George R. Pettit
Rok vydání:	1988
Předmět:	chemistry.chemical_classification Chromium chemistry.chemical_compound Sodium borohydride Chromium trioxide Ketone Chemistry Diol chemistry.chemical_element Organic chemistry Alcohol Alkaline hydrolysis (body disposal) Urushibara nickel
Zdroj:	J. Chem. Soc., Perkin Trans. 1. :2037-2041
ISSN:	1364-5463 0300-922X
Popis:	The syntheses of two new bufadienolides with ring-D oxygen substituents in abnormal configurations have been summarised. Sodium borohydride reduction of 3β-acetoxy-16-oxo-14β,15β-epoxy-5β-bufa-20,22-dienolide (3) provided a readily separable (1 : 1) mixture of 16α-deacetylcinobufagin (1a) and its previously known 16β-epimer. Also, 14-epi-bufotalin acetate (2a) was obtained by a sequence in which 14-dehydrobufotalin acetate (7) was epoxidised with m-perchlorobenzoic acid to give the diacetate (5a), selective alkaline hydrolysis of which gave the monoacetate (5b), which was then oxidised with chromium trioxide to give the ketone (8); reduction of (8) with chromium(II) acetate gave the alcohol (9), which was then reduced at the carbonyl to the diol (2b) with Urushibara nickel, and finally acetylated to afford the synthetic objective (2a).
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8eb560b35d2e147af4cbbd28fbc0833b https://doi.org/10.1039/p19880002037 Zobrazit plný text záznamu