The Influence of Condensed Cycle on Regiochemistry of Electrophilic Heterocyclization of 3‐Alkenyl‐2‐Thioxopyrimidin‐4‐One by pp ‐Alkoxyphenyltellurium Trichloride

摘要

> Electrophilic heterocyclization of 5‐alkenyl‐1‐methyl‐6‐thioxopyrazolo[3,4‐ d ]pyrimidin‐4‐ones and 3‐alkenyl‐2‐thioxoquinazoline‐4‐ones under the action of p ‐alkoxyphenyltellurium trichloride leads to annulation of thiazoline cycle with formation of 7‐[( p ‐alkoxyphenyl)telluromethyl]‐1‐methyl‐6,7‐dihydropyrazolo[3,4‐ d ][1,3]thiazolo[3,2‐ a ]pyrimidin‐4(1 H )‐ones hydrochlorides and 2‐( p ‐alkoxyphenyl)dichlorotelluromethyl‐2,3‐dihydro ‐ 5 H ‐[1,3]thiazolo[2,3‐ b ]quinazolin‐5‐ones hydrochlorides. Reduction of salts by the action of excess of sodium sulfite leads to formation of arylhetaryl telluride.