Vinod Dave

Synthesis of the allylic gonadal steroids, 3α-hydroxy-4-pregnen-20-one and 3α-hydroxy-4-androsten-17-one, and of 3α-hydroxy-5α-pregnan-20-one

Abstract A method for the convenient synthesis of the recently isolated allylic gonadal steroids, 3 α -hydroxy-4-pregnen-20-one (3 α -dihydroprogesterone; 3 α -DHP) and 3 α -hydroxy-4-androsten-17-one (3 α -HA), was developed using 4-pregnene-3,20-dione (progesterone) and 4-androstene-3,17-dione as substrates and potassium trisiamylborohydride (KS-Selectride) as reducing agent. Similar reactions were also used for the reduction of 5 α -pregnane-3,20-dione to 3 α -hydroxy-5 α -pregnan-20-one (3 α -HP). The yields were about 15%, 50%, and >90% for 3 α -DHP, 3 α -HA and 3 α -HP, respectively. Structures of the products, including the 3 β -isomers and the 17 α -epimer, formed in these reactions were determined by NMR and mass spectroscopic methods.

Synthesis and characteristics of allylic 4-pregnene-3,20-diols found in gonadal and breast tissues

Recently several allylic steroids have been found in gonadal and breast tissues. In order to establish their presence and identity in tissues and determine the possible biological properties, a method for the synthesis of 4-pregnene-3 alpha,20 alpha-diol, 4-pregnene-3 alpha, 20 beta-diol, 4-pregnene-3 beta,20 alpha-diol, and 4-pregnene-3 beta,20 beta-diol was developed using 4-pregnene-3,20-dione (progesterone) as substrate and freshly-prepared aluminum isopropoxide in isopropyl alcohol as reducing agent. The yields were about 19%, 30%, 13%, and 38% for the 3 alpha,20 alpha-, 3 alpha,20 beta-, 3 beta,20 alpha-, and 3 beta,20 beta-diols, respectively. The structures and stereochemistry of these diols were established using proton and carbon NMR spectroscopy and infrared and mass spectrometry.

On the Supposed Isoindole Synthesis from o-Tolunitrile

Abstract A recent communication1 in this journal reported the reaction of o-tolunitrile with sodium in tetrahydrofuran to yield a compound, m.p. 123.5–124°, to which was assigned the isoindole structure 1. A plausible mechanism can be written for the formation of 1 involving reductive dimerization of the cyano groups of two molecules of the nitrile, subsequent 1,5-hydrogen shift from a methyl group, disrotatory electrocyclic isoindole ring closure, and finally air oxidation and tautomerization to 1. Nevertheless, the evidence presented did not require an isoindole structure. Moreover, it would be unusual for a primary enamine to survive.