Reaction of nucleosides with thionyl chloride; Preparation of the deoxy derivatives of cytidine and adenosine

Abstract

On reaction of thionyl chloride with cytidine and adenosine in refluxing acetonitrile, the 5' -chloro-2',3' -sulphinyl derivatives I and VII are formed in a quantitative yield. On heating in dimethyl-formamide, compound I affords 5' -chloro-5' -deoxycyclocytidine (II) which is hydrolyzed in alkali to the arabinosyl derivative III; reduction of III with tributyltin hydride gives the 5' -deoxyarabinosyl derivative IV. The sulphinyl derivative I is hydrolyzed to 5' -chloro-5' -deoxycytidine (V) which is reduced to 5' -deoxycytidine (VI). Analogously, the sulphinyl derivative VII affords 5' -chloro-5' -deoxyadenosine (VIII) and the reduction of VIII gives 5' -deoxyadenosine (IX). Of these compounds, the 5' -chloro-5' -deoxyarabinosyl derivative as the only one shows an inhibitory effect towards the L1210 cell growth.