Ammonia → [(E)-1-[3-[(1R)-1-(5,7-difluoroquinolin-6-yl)ethyl]-[1,2,4]triazolo[4,3-b]pyridazin-6-yl]ethylideneamino] carbamate

Participants

Reaction Conditions

Reaction Steps

Previously prepared (E)-1-(3-(1-(5,7-difluoroquinolin-6-yl)ethyl)-[1,2,4]triazolo[4,3-b]pyridazin-6-yl)ethanone oxime (75-R, 100 mg, 0.271 mmol) in anhydrous THF (8 mL) was added diphosgene (0.1 mL, 0.829 mmol) dropwise at 0° C., and the reaction mixture was heated at 50° C. for 4 hr. Oil bath was removed, and the reaction mixture was cooled in an ice-water bath. An ammonia solution (0.5 N in dioxane, 8.0 mL, 4.0 mmol) was added dropwise. The temperature was allowed to rise to rt naturally, and the reaction mixture was stirred at rt overnight. Solvent was evaporated, and the residue was purified by column chromatography (8% methanol in ethyl acetate as eluent) to afford 64 mg (45.8% yield) of title compound as white solid, which was unstable at nucleophiles such as methanol, and was pro to degrade into starting material 75-R. 1H-NMR (400 MHz, DMSO-d6) δ ppm 8.96 (d, 1H), 8.44 (d, 1H), 8.34 (d, 1H), 8.10 (d, 1H), 7.56-7.74 (m, 2H), 7.34 (s br, 2H), 5.27 (q, 1H), 2.02 (d, 3H), 2.03 (s, 3H). LCMS (method B): [MH]+=412, tR=2.25 min.

Provenance & Evidence