One-pot three-component synthesis and oxidation of functionalized tetrahydrobenzo[d]pyrrolo[2,1-b]thiazoles

Triethylamine-promoted cycloaddition reactions of N-phenacyl and N-alkoxycarbonylmethylbenzothiazolium bromides with aromatic aldehydes and malononitrile (ethyl cyanoacetate, pivaloylacetonitrile) in ethanol afforded functionalized tetrahydrobenzo[d]pyrrolo[2,1-b]thiazoles in good yields and various diastereoselectivity. The oxidation reaction of the functionalized tetrahydrobenzo[d]pyrrolo[2,1-b]thiazoles with DDQ in different solvents resulted in diverse benzothiazole derivatives and benzo[d]pyrrolo[2,1-b]thiazoles. The reaction mechanism and the stereochemistry of this tandem [3 [Formula: see text] 2] cycloaddition reaction and sequential oxidation reaction are illustrated based on analysis of the reactive intermediates and obtained products.