Synthesis of (19E)-3β,7α-dihydroxy-17-oxoandrost-5-en-19-al 19-(O-carboxymethyl)oxime, a new hapten for 7α-hydroxydehydroepiandrosterone (3β,7α-dihydroxyandrost-5-en-17-one)

The title compound was prepared in 11 steps from 17, 17-ethylenedioxy-19-hydroxyandrost-5-en-3 beta-yl acetate. After tert-butyldimethylsilyl protection of the the 19-hydroxyl group, a 7-oxo group was introduced by oxidation with 3, 5-dimethylpyrazole-chromium trioxide complex, and then selectively reduced with L-Selectride(R) to give a 7 alpha-hydroxy derivative. This partially protected triol was acetylated and desilylated to 3, 7-diacetate. Subsequent oxidation with pyridine-chromium trioxide complex gave 19-aldehyde, which was transformed into the corresponding protected 19-(O-carboxymethyl)oxime. Successive ketal cleavage, deacetylation, and methyl ester splitting gave the Sinal (19E)-3 beta, 7 alpha-dihydroxy-17-oxoandrost-5-en-19-al 19-(O-carboxymethyl)oxime, designed as a hapten for 7 alpha-hydroxydehydroepiandrosterone immunoassays. (C) 1998 by Elsevier Science Inc.