Synthesis of 5‐aryl‐2‐oxazolepropionic acids and analogs. Antiinflammatory agents

Condensation of 2‐bromoacetophenones with sodium succinimide gave N ‐phenacylsuccinimides ( 1 ) which were opened with sodium hydroxide to N ‐phenacylsuccinamic acids ( 2 ). The latter were cyclized to 5‐aryl‐2‐oxazolepropionic acids ( 3 ) in sulfuric acid. Similar cyclization of N ‐phenacylphthalamic acid ( 5 ) and succinic acid 2‐benzoylhydrazide ( 7 ) gave o ‐(5‐phenyl‐2‐oxazolyl)benzoic acid ( 6 ) and 5‐phenyl‐1,3,4‐oxadiazole‐2‐propionic acid ( 8 ). The succinamic acids 2 and the phthalamic acid 5 were observed to recyclize to the corresponding imides ( 1 and 4 ) on heating, and the succinic acid hydrazide 7 was similarly cyclized to N ‐benzamidosuccinimide ( 9 ) with acetic anhydride. Antiinflammatory screening data are reported for 3 , 6 and 8 .