INTRAMOLECULAR REARRANGEMENT .4. INTRAMOLECULAR ALKYL REARRANGEMENTS AND TAUTOMERISM OF QUINAZOLINONE DERIVATIVES

The structure of a condensation product of anthranilic acid with ethyl benzimidate was determined on the basis of the comparison of its NMR, IR, UV data and elemental analyses with those of model compounds. The IR, UV and NMR spectra show that the most stable tautomer among three possible structures is 2-phenyl-4(3H)-quinazolinone. This conclusion is supported by the fact that the Me group of 1-methyl-2-phenyl-4(1H)-quinazolinone rearranges intramolecularly to give 3-methyl-2-phenyl-4(3H)-quinazolinone when the former is heated at elevated temperatures. © 1969.