Reaction of 2,4-dinitrobenzenediazonium ions with thiophens. Part 1. An acidic Gomberg reaction

Abstract

The reaction of 2,4-dinitrobenzenediazonium ions with a number of thiophen derivatives has been investigated. Under conditions in which 2,4-dinitrobenzenediazonium ions couple with anisole to yield an azo-dye, the same ions interact with thiophen with evolution of nitrogen to yield 2-(2,4-dinitrophenyl)thiophen. Similar arylation occurs with the two monomethylthiophens and with benzo[b]thiophen. Other alkylthiophens undergo coupling reactions (see following paper). Mechanisms for the arylation reaction are discussed.