Thermal stability of 7-trimethylsilylperoxy-cholest-5-ene 3b-acetates at high temperature

Abstract

The thermal degradation of the two hydroperoxy isomers (7a- and 7b-hydroperoxides) of cholest-5-ene 3b-acetate (CA) generates many products, of which most have already been identified; the two 7-hydroxy-CA a- and b-isomers are among these compounds. In the case of the 7a-hydroperoxy-CA degradation, the isomer 7a-hydroxy-CA is present in a high proportion, while the 7b-isomer is generated in a larger amount from the 7b-hydroperoxy-CA. The thermal degradation of the trimethylsilyl derivatives (TMS) of the 7-hydroperoxy-CA gives rise to many products, of which several components are the same as those obtained from the corresponding non silylated 7-hydroperoxy-CA isomer. We have found an unexpectedly high amount of the TMS derivative of the 7-hydroperoxy-CA (7a- or 7b-isomers). Traces of free 7a-hydroperoxy-CA, from thermal degradation of each 7-hydroperoxide-CA TMS (7a- and 7b-isomers), were also found.