Trimethyl phosphite → Phosphonic acid, (5-methoxy-2-methyl-1,1-dioxido-2H-1,2,4,6-thiatriazin-3-yl)-, dimethyl ester

Participants

Reaction Conditions

Reaction Steps

145 parts of trimethyl phosphite were added, in the course of 40 minutes, to 165 parts of 5-chloro-6-methyl-3-methoxy-6H-1,2,4,6-thiatriazine-1,1-dioxide in 550 parts of toluene at from 38° to 41° C., while stirring. The reaction mixture was heated to 70° C. in the course of 30 minutes, and stirring was continued at this temperature for 13/4 hours. Thereafter, the solution was decanted off from the small amount of tacky residue, and was freed from volatile constituents at 80° C./0.2 mbar. The residue was dissolved in 300 parts of ethyl acetate, and the solution was chromatographed over neutral aluminum oxide. After evaporating down under reduced pressure, 192 parts (96% of theory) of 6-methyl-3-methoxy-5-dimethylphosphono-6H-1,2,4,6-thiatriazine-1,1-dioxide of nD25 =1.4998 were obtained.

Provenance & Evidence