Novel and one‐pot Synthesis of Tetrahydropyrrolo[1,2‐ a ]‐2‐Methylbenzothiazole‐3‐Spiro‐1 ′ ‐Cyclohexa‐2 ′ ,5 ′ ‐Dien‐4 ′ ‐one‐4,5‐Dicarboxylate Derivatives via a Three Component Reaction

The three component condensation reactions involving 2‐methylbenzothiazole or 2,5‐dimethylbenzothiazole, dialkyl acetylenedicarboxylate, and 2,6‐dimethyl phenol or 2,6‐di‐tert‐butylphenol constitute a novel and one‐pot synthesis of tetrahydropyrrolo[1,2‐ a ]‐2‐methylbenzothiazoles‐3‐spiro‐1 ′ ‐cyclohexa‐2 ′ ,5 ′ ‐dien‐4 ′ ‐one‐4,5‐dicarboxylate derivatives in good yields. The reactions proceeded at room temperature without using any catalyst. This method is very useful to functionalize benzothiazole derivatives in a one‐pot operation.