3-[ 5-(4-Acetamidophenyl)-2-tet1azolyl]propionic Acid (14). A solution of 5 g (0.022 mole) of 3-(5-(4-aminophenyl)-2-tetrazolyl]- propionic acid 34 in 200 ml of Ac,O was allowed to stand for 24 hr at room temperature. The reaction was diluted with 2 1. of water and the solid collected and dried. Recrystallization from MeOH gave 2.4 g (40%) of fine white needles, mp 218”. 3-[5-(4-Phenylazophenyl)-2-tetrazolyl]propionic Acid (16). A solution of 10 g (0.043 mole) ...