Synthesis of Functionalized 2‐Oxo‐2H‐benzo[h]chromene‐3‐carbonitriles from 1‐Tetralones

Abstract

AbstractWe have developed a facile oxidative approach for the synthesis of C‐4 functionalized 2‐oxo‐2H‐benzo[h]chromenes. The required precursors, 4‐(methylthio)‐2‐oxo‐5,6‐dihydro‐benzo[h]chromenes were synthesized by reaction of 1‐tetralones and 2‐cyano‐3,3‐bis(methylthio)acrylate under basic conditions, which can be further aminated with different secondary amines in refluxing ethanol. We have reported the NBS and AIBN mediated oxidation of 5,6‐dihydro‐benzo[h]chromenes to afford 4‐(substituted)‐2‐oxo‐benzo[h]chromenes. The scope of dehydrohalogenation was further extended for the synthesis of thiophene‐fused chromenes. Reactivity of synthesized 4‐(substituted)‐2‐oxo‐benzo[h]chromenes was also explored with C‐ and S‐nucleophiles.