Facile synthesis of acyclic analogues of carbocyclic nucleoside as potential anti-HIV pro-drug

Abstract

Microwave induced montmorillonite K 10 clay catalyzed Michael addition of sulphur nucleophile, (4-oxo-butyl)-dithio­carbamic acid <b style="">1</b> to 4-arylidene-5(4<i style="">H</i>)-oxazolones <b style="">2a-j</b> followed by ring transformation of the resultant Michael adducts <b style="">3a-j</b> in solvent-free conditions gives <b style="">4a-j </b>in excellent yield. Coexistence of acidic and basic sites on surface of montmoril­lonite K 10 accelerates the organic reactions synergistically. The control Aldol condensation of compound <b style="">4a-j</b> with HCHO gives compound <b style="">5a-j</b>, which upon chemoselective reduction with NaBH₄ gives the title compound <b style="">6a-j</b>. This process minimizes the mechanical loss of the intermediate during the process of isolation, and thus increases the yield and decreases the cost and time.