Hydroxylation of prostanoids by fungi. Synthesis of (-)-15-deoxy-19-(R)-hydroxy-PGE1 and (-)-15-deoxy-18-(S)-hydroxy-PGE1

Article abstract of DOI:10.1139/v90-039

A series of racemic substituted cyclopentanones, with alkyl groups corresponding to the upper prostanoid side chain and (or) the lower prostanoid side chain without the C-15 alcohol, has been synthesized. Using a steroid template for the prostanoid molecule as a basis for selection, fungi capable of hydroxylating steroids have been used to biotransform the prostanoid substrates. The predominant products were hydroxylated at the prostanoid C-18 and C-19 positions. The hydroxylations were enantioselective, with excesses in the range 10-60%, and in most cases the predominant configuration corresponded to that of the natural prostanoids. The sterochemistry of the C-19 hydroxyl group was found to be R by degradation of products to methyl 6-acetoxyheptanoate and comparison of that material with a resolved sample, obtained via crystallization of the brucine salt of ethyl 6-phthaloxyheptanoate. Hydroxylation at C-18 gave the S configuration of alcohol. Hydroxylation at prostanoid C-15 was observed, but in all cases this was accompanied by other reactions. Hydroxylation of Rhizopus arrhizus has been used in a preparation of (-)-15-deoxy-19-(R)-hydroxy-PGE₁ and (-)-15-deoxy-18-(S)-hydroxy-PGE₁.