J. Kashyap et al., SYNTHESIS OF 4-ARYLIDENE-2-PHENYLOXAZOL-5-ONES USING 1 1 MIXTURE OF AL2O3-H3BO3/, Synthetic communications, 28(22), 1998, pp. 4187-4191
Cyclodehydration-condensation of hippuric acid and arylaldehydes have
been carried out using a 1:1 mixture of Al2O3-H3BO3 in the presence of
stoichiometric quantity of acetic anhydride to give the target compou
nd in good yield. This procedure can be used to synthesize the 4-alkyl
idene analogs also.