High-temperature continuous flow synthesis of 1,3,4-oxadiazoles via N-acylation of 5-substituted tetrazoles

Applying continuous flow processing in a high-temperature/high-pressure regime (200–220 °C, 11–14 bar) 2,5-disubstituted-1,3,4-oxadiazoles are prepared in high yields within 5–10 min residence time by treatment of 5-substituted-1H-tetrazoles with anhydrides or acid chlorides as electrophiles (Huisgen reaction).