| 摘要 |
<p>A method of preparation of 4,5alpha-epoxy-6-oxomorphinan derivatives of formula (I), wherein R<1> is hydrogen, methyl, or ethyl and R<2> is hydrogen, methyl, cyclobutylmethyl or benzyl, in which compounds of formula (II), wherein R<1> and R<2> are as defined with respect to compounds (I), are isomerized into compounds of formula (I) in the presence of a mixed catalyst containing at least two elements from the group of platinum metals. The method provides the product in high yield and with low contents of impurities.</p> |
