Modified Pregnanes

Particularly because of the potential importance of the spirosolane alkaloids as starting materials for the industrial production of hormonal steroids, a munber of modified irosolanes have been synthesized. The d radation of these products (see Swtion IV,C) should lead to modified pregnanes. 

Many of the foregoing modified progesterone analogues exhibit improved biopharmaceutical properties over progesterone proper. The derivatives that follow were likely prepared in the hope that combinations of substituents would lead to additive improvements, a circumstance that often prevails in the pregnane series. 

Side-chain Cleavage.—The formation of pregnane derivatives in plants is probably similar to that in animals 20a-hydroxycholesteroT and tomatine (90) are metabolized in this way. In mammalian systems modified steroids... 

The A -corticoids, which can be prepared by microbial dehydrogenation of cortisone or hydrocortisone with Corynebacterium simplex (41) and by several synthetic methods (33), represent the first chemical innovation leading to the creation of a modified compound that could be prescribed for rheumatoid arthritis. One high-yield route involves oxidation of 5a- or 5(3-pregnane precursors that have appropriate oxygen substitutions with selenium dioxide (42). 

In the area of glycoslated steroids the a-L-rhamnosyl derivative of cholesterol has been made by a modified Lewis acid-catalysed route, and several standard syntheses of 17-glucosylated androstane and estradiol derivatives have been reported. Likewise, 3-p-hydroxy-5a-pregnan-20-one has been /3-glucosylated. ... 

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