Carbonylation of o-amino-N-(1,1-dimethylprop-2-ynyl)-benzamide 3 with ethyl chloroformate gave 2-carbethoxyamino-N-(1,1-dimethylprop- 2-ynyl)-benzamide 6. Attempted cyclization of 6 under basic conditions did not give the quinazoline 8 but an oxazole 7. When 3 was also refluxed in triethylorthoformate-acetic anhydride mixture, 2-acetylamino-N-(1,1-dimethylprop- 2-ynyl)-benza-mide 4 was formed as the major compound with negligible amount of 3-(1,1- dimethylprop-2-ynyl)-quinazolin-4-(3H)-one 5.