Synthesis of 1,2,4-triazole-fused heterocycles by tandem appel dehydration/thermal rearrangement methodology

Article abstract of DOI:10.1055/s-1997-1380

The reaction of α-substituted benzophenone 1-acetamidoethylidenehydrazones 6b,c and 13a-d with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine in dichloromethane (Appel's condition) provides a general route to a variety of 1,2,4-triazole-fused heterocycles such as compounds 9-11, 16a-d, 17b-d, and 18 via the thermal rearrangement of the expected amino ketenimine intermediates.