Photo-induced transformations. Part 51. Photo- and thermally-induced rearrangements of hypoiodites of steroidal homoallyl alcohols. The formation of some oxygen heterocycles via photo- and thermally-induced rearrangements of 3-hydroxy-Δ<sup>5</sup>-steroid hypoiodites in the presence of mercury(<scp>II</scp>) oxide and iodine
Hypoiodites of cholesterol and epicholesterol in benzene containing mercury(II) oxide and iodine underwent photo-induced rearrangement to give 3α,5-epoxy-6β- and -6α-iodo-A-homo-4-oxa-5α-cholestanes (3) and (4), together with 3-formyloxy-2-iodo-A-nor-2,3-secocholest-5-ene (2). Stereochemistry of the epoxide (3) was established by an X-ray crystallographic analysis. When the reaction of cholesterol
[3α-2H]- and [5-2H]-3β-hydroxy-5β-cholest-7-en-6-ones were converted with a hairy root culture of Ajugareptansvar. atropurpurea into 20-hydroxyecdysone, in which the deuterium atoms retained their original positions, thus strongly suggesting that 3β-hydroxy-5β-cholest-7-en-6-one is an obligatory intermediate in the biosynthesis of ecdysteroids in the plant.
Motional anisotropy-induced unequal deuterium NMR spin-lattice relaxation of 3α-deuteriocholesterol and 3β-deuterioepi-cholesterol in solution as a measure of sterol motion about the molecular axis
作者:Martha P. Murari、Ramaswamy Murari、Wolfgang J. Baumann
DOI:10.1002/mrc.1260230406
日期:1985.4
rapid reorientations (τc ≈︁ 10−11s) in solution, the relaxation of the deuterium in 3β‐deuterioeholesterol was approximately 2.5 times faster than in 3β‐deuterioepicholesterol. These unequal rates of relaxation are due to the difference in the angles between the CD bond and the molecular axis for the two sterol isomers. An equation containing an angular‐dependent term was derived to analyze the T1 data