An ester migration in the rearrangement of a diels–alder adduct of a furan and a phenyl migration in the rearrangement of methyl 3,3,5-triphenylpyrazole-4-carboxylate

Abstract

Methyl 5-methoxyfuran-2-carboxylate reacts with dimethyl acetylenedicarboxylate to give trimethyl 3-hydroxy-6-methoxybenzene-1,2,4-tricarboxylate, identified from its spectra and its conversion into diethyl 2,5-dihydroxyterephthalate. The thermal rearrangement of methyl 3,3,5-triphenyl-3H-pyrazole-4-carboxylate proceeds by a phenyl, and not by an ester, migration.