The Boulton–Katritzky rearrangement of isocarboxazid

Abstract

magnified imageIsocarboxazid rearranges on heating to 5‐acetonyl‐2‐benzyl‐4‐hydroxy‐1,2,3‐triazole in DMF at 150°C, in the ionic liquid, [bmin]HSO at 100°C or as a melt at 105°C. This is the first reported example of the Boulton–Katritzky rearrangement of an acyl hydrazide. J. Heterocyclic Chem., (2009)

Exploiting the CNC Side Chain in Heterocyclic Rearrangements: Synthesis of 4(5)-Acylamino-imidazoles

“…The Boulton−Katritzky (BK) rearrangement represents one of the most investigated ring-transformation reactions as a result of its synthetic applications , and intriguing mechanistic aspects. , …”

“…It consists of an interconversion between two five-membered heterocycles where a three-atom side chain and a pivotal annular nitrogen are involved ( 1 → 2 ) . This rearrangement typically occurs on O−N bond-containing heterocycles (D = O) , with the O(1) ring oxygen acting as an internal leaving group. The O−N bond is cleaved by the nucleophilic attack of the side-chain Z atom at the electrophilic N(2) ring nitrogen.…”

Chemistry of 1,2,3-triazoles

“…[319][320][321][322].Scheme 83 Rearrangement of the hydrazone of benzo[d]isoxazole 236 to 2-aryl-2H-1…”