Acetic Acid → 4-(2-Fluoro-3-{[5-oxo-1-(3-oxo-3,4-dihydro-2H-1,4benzoxazin-6-yl)pyrrolidin-3-yl]amino}propyl)-6-methoxypyrido[2,3-b]pyrazin-3(4H)-one

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Reaction Steps

A crude product of 2-Fluoro-3-(6-methoxy-3-oxopyrido[2,3-b]pyrazin-4(3H)-yl)propanal (323 mg), 6-(4-amino-2-oxopyrrolidin-1-yl)-2H-1,4-benzoxazin-3(4H)-one (Reference Example 6; 227 mg, 0.917 mmol) were mixed in a mixed solution of dichloromethane (30 ml) and N,N-dimethylformamide (3 ml). Acetic acid (0.105 ml, 1.834 mmol) and anhydrous sodium sulfate (450 mg) were added to the solution and the mixture was stirred for 12 hours. Sodium triacetoxyborohydride (389 mg, 1.834 mmol) was added to the reaction solution, the mixture was stirred for 4 hours and then the solvent was removed under reduced pressure. A lower layer solvent of chloroform/methanol/water (7:3:1) was added to the residue and the resultant was alkalized by adding saturated sodium bicarbonate water under cooling on ice. The mixture was extracted with a lower layer solvent of chloroform/methanol/water (7:3:1), the extract was dried over anhydrous sodium sulfate and the solvent was removed under reduced pressure. The residue was purified by silica gel column chromatography (chloroform/methanol) and preparative layer chromatography (silica gel, chloroform/methanol=20:1) to yield 180 mg (41%) of the title compound in the form of a light orange solid.

Provenance & Evidence