Heterocyclic polyfluoro-compounds. Part 39. Preparation and some nucleophilic substitution reactions of trifluoro-1,2,4-triazine

Abstract

Fluorination of trichloro-1,2,4-triazine over potassium fluoride at 450 °C in a flow system yields trifluoro-(91%) and 6-chloro-3,5-difluoro-1,2,4-triazine (5%). The trifluorotriazine yields a dimer with time, which reverts to the monomer with potassium fluoride at 250 °C, and gives 6-fluoro-1,2,4-triazine-3,5(2H,4H)-dione (45%) with water, 5-amino-3,6-difluoro-1,2,4-triazine (76%) with ammonia, a 3,5-bis(4-chloroanilino)-derivative (50%) with p-chloroaniline, 3,5-bis(diethylamino)-6-fluoro-1,2,4-triazine (45%) with diethylamine, and a 1 : 2 mixture of 3,5- and 5,6-dimethoxy-derivatives (41%) with methanol.