Synthesis of Benzoxazolones
2-phenoxycarbonyl-4,5-dichloropyridazin-3(2H)-one is a solid stable carbonyl source that is a recyclable. The reagent enables the synthesis of benzo[d]thiazol-2(3H)-ones, benzo[d]oxazol-2(3H)-ones, and benzo[d]imidazol-2(3H)-ones using in one pot out under neutral or acidic conditions to give the corresponding heterocycles in very good yields.
K. E. Ryu, B. R. Kim, G. H. Sung, H. J. Yoon, Y.-J. Yoon, Synlett, 2015, 26, 1985-1990.
Benzoxazolone pharmacophore is present in many compounds having a wide spectrum of biological activities. Treatment of N-alkyl-N-arylhydroxylamines with trichloroacetyl chloride and triethylamine afforded 3-alkylbenzoxazolones generally in good yields at ambient temperatures. The present method is mild, wide in scope, economical, and regioselective. Many sensitive groups are tolerated.
R. N. Ram. V. K. Soni, J. Org. Chem., 2013, 78, 11935-11947.