4-(2′-Hydroxyphenylmethylene)-2-phenyloxazol-5(4H)-one: a comedy of errors

Abstract

Eighteen publications since 1955 have described properties and reactions of the title compound. All these reports are erroneous and refer, variously, to three other substances. All literature reports of the analogous 4-(2′-hydroxyphenylmethylene)-2-methyloxazol-5(4H)-one also need revision. A convenient synthesis of the title compound 3(RH), its chemical and physical properties, and its rearrangement to 3-benzoylamino-1 -benzopyran-2-one 1, are reported here for the first time. A mechanism is presented for the observed course of Plöchl–Erlenmeyer syntheses with salicylaldehyde and with 2-acetoxybenzaldehyde.