4-chloro-1-(difluoromethyl)-1H-pyrazole-3-carbaldehyde → (S)-4-{5-[(4-chloro-1-difluoromethyl-1H-pyrazol-3-ylmethyl)-amino]-2-fluoro-phenyl}-4-methyl-5,6-dihydro-4H-[1,3]oxazin-2-ylamine

Participants

Reaction Conditions

Reaction Steps

In a 5 ml-reaction tube a solution of (S)-4-(5-amino-2-fluoro-phenyl)-4-methyl-5,6-dihydro-4H-[1,3]oxazin-2-ylamine (intermediate A8.4) (22 mg, 0.1 mmol) in methanol (0.3 ml) was treated at room temperature at under an inert atmosphere with 4-chloro-1-difluoromethyl-1H-pyrazole-3-carbaldehyde (19.9 mg, 110 μmol). The tube was closed and the reaction mixture was stirred at 25° C. for 60 minutes. Then decaborane (24.4 mg, 200 μmol) was added in one portion, the tube was closed, and the mixture was warmed to 45° C. for 15 hours. For the workup, the reaction solution was quenched with a solution of sodium carbonate (10%). Methanol was removed at reduced pressure, then the residue was extracted three times with ethyl acetate. The combined organic layers were dried over sodium sulphate and evaporated at reduce pressure. The crude product was purified by basic preparative HPLC and after evaporation triturated with a mixture of ether and heptane. The (S)-4-{5-[(4-chloro-1-difluoromethyl-1H-pyrazol-3-ylmethyl)-amino]-2-fluoro-phenyl}-4-methyl-5,6-dihydro-4H-[1,3]oxazin-2-ylamine (8 mg, 20% yield) was obtained as a colorless oil. MS (ISP): m/z=388.2 [M+H]+.

Provenance & Evidence