Absolute stereochemistry of citrinadins a and B from marine-derived fungus.
[Structure: see text]. Citrinadin A (2) is a pentacyclic indolinone alkaloid isolated from the cultured broth of a fungus, Penicillium citrinum, which was separated from a marine red alga. The absolute stereochemistry of the pentacyclic core in 2 and its new congener, citrinadin B (1), was elucidated by analysis of the ROESY spectrum for the chlorohydrin derivative (3) of 1 as well as comparison of the electronic circular dichroism (ECD) spectra for 1 and 2 with those of known spirooxiindole alkaloids. On the other hand, the absolute configuration at C-21 bearing an epoxide ring was assigned as S by comparison of the vibrational circular dichroism (VCD) spectra of 1 with those of model compounds 2S- and 2R-2,3-epoxy-3,3-dimethyl-1-phenylpropan-1-one (4a and 4b, respectively).
Mugishima
Takao
T
Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
Tsuda
Masashi
M
Kasai
Yuu
Y
Ishiyama
Haruaki
H
Fukushi
Eri
E
Kawabata
Jun
J
Watanabe
Masayuki
M
Akao
Kenichi
K
Kobayashi
Jun'ichi
J
D000470:Alkaloids / Q000737:chemistry; D002942:Circular Dichroism; D026121:Indole Alkaloids; D011807:Quinolizines / Q000737:chemistry*; D000461:Rhodophyta / Q000737:chemistry*; D013237:Stereoisomerism; D014633:Valine / Q000031:analogs & derivatives* / Q000737:chemistry
D000470:Alkaloids; D026121:Indole Alkaloids; D011807:Quinolizines; C503673:citrinadin A; D014633:Valine