5,6,7,8‐Tetrafluoro‐1‐(2‐nitrophenyl)‐3‐phenyl‐1H-benzo[e][1,3,4]oxadiazine

Abstract

Treating 1‐fluoro‐2‐nitrobenzene (6) with N′‐pentafluorophenylbenzohydrazide (7) and K2CO3 (1.1 equiv) in EtOH at ca. 110 °C (sealed tube) for 24 h affords 5,6,7,8‐tetrafluoro‐1‐(2‐ nitrophenyl)‐3‐phenyl‐1H‐benzo[e][1,3,4]oxadiazine (5) (36%) and N′‐(2‐nitrophenyl)‐N′‐ (perfluorophenyl)benzohydrazide (3) (37%). The X‐ray crystallography of 5,6,7,8‐tetrafluoro‐1‐(2‐ nitrophenyl)‐3‐phenyl‐1H‐benzo[e][1,3,4]oxadiazine (5) is provided. Microwave irradiation (100 W) of perfluorophenylbenzohydrazide 3 with K2CO3 (1.1 equiv) in THF at ca. 120 °C (sealed tube, 80 PSI) for 3 h gives oxadiazine 5 (85%), while reduction of the nitro group using Sn (4 equiv) in glacial acetic acid at ca. 20 °C for 30 min, followed by cyclodehydration at ca. 118 °C for 20 min and treatment with 2 M NaOH for 24 h resulted in 1‐(perfluorophenyl)‐3‐phenyl‐1,2,4‐benzotriazin‐4‐yl (4) with 93% yield.