5-[2-(2,4,6-Trifluorophenyl)-acetylamino]-pyridazine-4-carboxylic acid ethyl ester → 3-(2,4,6-trifluorophenyl)-1H-pyrido[2,3-d]pyridazine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

The product from Step 1 (2.5 g) was dissolved in dry THF (50 ml) and the flask purged with nitrogen. Sodium bis-trimethylsilylamide (22.1 ml of a 1M solution in THF) was added dropwise with stirring at 0° C. A yellow precipitate appeared, and the reaction was stirred for 3 hours at 0° C. The reaction was quenched with concentrated hydrochloric acid (5 ml) at 0° C. and then poured onto ice water, extracted with DCM and dried over magnesium sulphate. The solvent was evaporated to give 3-(2,4,6-trifluorophenyl)-1H-pyrido[2,3-d]pyridazine-2,4-dione as a yellow solid. Further product crystallised out of the aqueous solution overnight, to give a total yield of 1.29 g, m.p. >300° C.

Provenance & Evidence