Kazuo Tori

Components of the root of Lindera strychnifolia vill.—XI : Configuration of the cyclopropane-ring in linderene and the structure of isodihydrolinderene

Abstract Linderene and its dihydro-derivatives were converted to the corresponding unsaturated enol lactones (III, IXa and XIIa) by the action of dichlorodicyanobenzoquinone. These unsaturated enol lactones (IXa and XIIa) gave the triene lactones (XVI and XVII). Configuration of the cyclopropane ring in linderene was assigned as β from the results of the NMR spectra of XVI and XVII. The structure of isodihydrolinderene was also confirmed by comparison of the NMR spectra of XIIa and its acetate (XIIb).

Conformation of ring a in acetonides of 2β,3α-mercaptocholestanols evidenced by NMR spectroscopy : Bile acids and steroids. XXX: Thiosteroids. 15

Abstract Conformations of ring A in five 4,5-disubstituted 2,2-dimethyl[1,3]oxathiolanes fused at the 2- and 3-positions of 5α-cholestane (I–V) and two at the 3- and 4-positions (VI and VII) are studied by NMR spectroscopy in connection with the oxathiolano-ring closure of 2β,3α-rans-diaxial mercapto-ols with acetone. Evidence was obtained for skewed-boat conformations of ring A in the former two 2β,3α-derivatives (I and II) and for slightly distorted-chair conformations of ring A in the latter derivatives (V–VII).

Structure of sericenine

The configuration of the double bonds in sericenine, a component of the leaf of Neolitsea sericea Koidz., has been elucidated by application of the Nuclear Overhauser Effect, thus completing the assignment of structure.

Proton magnetic resonance studies of citral a and b

All the proton magnetic resonance signals of citral a (I) b (II) have been assigned by use of the spin-decoupling method and by application of nuclear Overhauser effects. s-trans Conformations of the aldehyde groups have been confirmed by use of the solvent effect of benzene. The conclusions are consistent with those of earlier workers.