SYNTHESIS OF CARBOCYCLIC ANALOGS OF PURINE RIBONUCLEOSIDES

The racemic forms of the carbocyclic (cyclopentane) analogs of adenosine, inosine, 6-mercaptopurine ribonucleoside, and 6-(methylthio)purine ribonucleoside were synthesized from (±)-4β-amino-2α,3α-dihydroxy-1 β-cyclopentanemethanol. This amine was synthesized by two routes irom 2α, 3α-diacetoxy-1β,4β-cyclopentanedi-carboxylic acid via its anhydride and monoamide. The two routes differed in the order in which the amino group was introduced by a Hofmann reaction and the hydroxymethyl group, by metal hydride reduction of an ester or acid chloride group. The stereochemistry of the starting cyclopentane was fixed by the preparation of this compound from exo-cw-5-norbornene-2,3-diol, which was prepared by cis-dihydroxylation of norbornadiene. The structure of the norbornenediol was confirmed by chemical means and by nmr analysis. © 1969, American Chemical Society. All rights reserved.