Controlling substitution patterns on the 1,2,4‐triazolo[1,5‐α]‐pyrimidine ring. Selective removal of chlorine at the 7‐position

Abstract

AbstractA highly effective method for the selective removal of chlorine from the 7‐position of the 1,2,4‐triazolo[1,5‐α]pyrimidine ring in the presence of chlorine at the 5‐ or 6‐positions is reported. The method involves treatment of the appropriate substrate with zinc‐copper couple in the presence of acetic acid in methanol‐tetrahydrofuran. The method enables the construction of a variety of substitution patterns in key intermediates for the 1,2,4‐triazolo[1,5‐α]pyrimidine sulfonanilide herbicides.