Reactions of 6‐thiotheophylline with alkylating agents and epichlorohydrin: Isolation of S ‐alkylated 6‐thiotheophylline and 7‐(2,3‐thioepoxypropyl)theophylline

Alkylation of 6‐thiotheophylline ( 1 ) under the aprotic basic condition affords S ‐alkylated 6‐thiotheophylline ( 3 ) together with an N 7 ‐alkylated product 4 . There is a tendency that the more reactive the alkylating agents are, the higher the yields of S ‐alkylated products are. On the other hand, treatment of 6‐thiotheophylline ( 1 ) with epichlorohydrin afforded an unexpected product, 7‐(2,3‐thioepoxypropyl)theophylline ( 6 ), neither an S ‐alkylated compound 3g nor an N 7 ‐alkylated compound 4g . The chemical structure was determined by nmr spectroscopic analysis.