The isolation and structure of new bufadienolide, resibufagin and the isolation of marinobufagin

✍ Scribed by Yoshiaki Kamano; Hiroshi Yamamoto; Katsuo Hatayama; Yoshihiro Tanaka; Michiko Shinohara; Manki Komatsu

• Publisher: Elsevier Science
• Year: 1968
• Tongue: French
• Weight: 193 KB
• Volume: 9
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)70747-7

✦ Synopsis

Among some twenty bufadienolides hitherto known, thirteen of them were isolated') from the Chinese toad venom drug, Ch'an Su (s k).

We have recently described3)

on the detection of unknown compounds from Ch'an Su by using thin-layer chromatography.

This report concerns with the isolation and characterization of them.

The chloroform extract of Ch'an Su4) afforded a mixture of unknown materials by column chromatography on silica gel which was eluted by adopting the dry method5) using an A-hexane-acetone mixture. By rechromatography of the mixture, there were obtained two bufadienolides, one of which was identified to be marinobufagin (V)@, first isolation from Ch'an Su. The other compound, mp. 210-212") which was obtained as colorless needles from methanol, was named resibufagin. Based on the following evidence, structure I (3 p-hydroxy-19-0x-14, 15 P -epoxy-5 P -bufa-20,22-dienolide) was assigned to the new bufadienolide. From molecular weight determination (m/e 398) and elemental analysis the compound was found to have the formula C24H3005. The presence of an &-pyrone ring was indicated from W ( \ 22 301 my, loge 3.60) and IR spectra ( r/E2 1714, 1630, 1535 cm-l). The structure was supported by the NMR spectra (CBC13), which exhibited signals at Z 2.24 (lH, dd, J = 3 and IO cps, C22-H), 2.77 (lH, dd, J = 3 and 1 cps, C21-H) and 3.79 (lH, dd, J = 10 and 1 cps, C23-_ . H) ') The appearance of a signal at a low field of Z 0.50 (lH, s) indicated the presence of a formyl group, the location of which was deduced to be Cl0 based on analogy with