A convenient and efficient one-pot synthesis of 2,5-disubstituted-1,3,4-oxadizoles is described. Various carboxylic acid hydrazides reacted efficiently with different carboxylic acid chlorides and 10-camphorsulfonic acid. This methodology was successfully applied to the synthesis of a series of 2H-chromene substituted 1,3,4-oxadiazole derivatives in good to high yields.
