Shinobu Iriuchijima

Asymmetric hydrolysis of 3-acetylthiocycloheptene and 3-acetoxycycloheptene with a microbial lipase

With a lipase from Candida cylindracea(±)-3-acetylthiocycloheptene was hydrolysed with greater stereoselectivity than (±)-3-acetoxycycloheptene, in both esters the (+)-isomers being preferentially hydrolysed.

Chemistry of Heliangine: Part I. Structure of Heliangine

The evidences which allow to assign the partial structures (a, b and c) for heliangine, C20H26O6, are described. The chemical and spectroscopic data obtained for this compound are interpreted in terms of the structure I, which has been preliminarily proposed by the authors, as well as of the structure II established by X-ray analysis conducted by Nishikawa et al.

Chemistry of Heliangine:Part II. Analyses of an ABC System in the 60 and 100 Mc NMR Spectra of Helianginone

Novel three-proton signals at δ3.6~2.0 in the 60 and 100Mc NMR spectra of helianginone (II) were interpreted by several analytical methods. These protons were concluded to form an isolated ABC system which contains two chemical shifts, δAC= 100.2 and δBC= 81.6 cps, and three coupling constants, JAB=4.9, JBC= 10.2 and JCA= -14.8 cps. In this system it is very significant that JCA is negative. These protons were assigned as in the partial structure (a) of II.