Dimethylformamide → 4-Oxo-1-((3'-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylic acid

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Reaction Steps

To a light brown solution of ethyl 4-oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate (32) (114 mg, 0.252 mmol) in methanol (10 mL) was added the solid lithium hydroxide monohydrate (211 mg, 5.04 mmol) at room temperature under a nitrogen atmosphere. The resulting brown solution was stirred for 15 h at which time LCMS analysis indicated the absence of starting material. Then, the reaction mixture was diluted with water and the methanol was removed under vacuum. The basic aqueous solution contains some solids which were dissolved by addition of 5 mL of dimethylformamide and then it was neutralized with 1.0N HCl. Then, the organic compound was extracted into ethyl acetate (2×50 mL) and the combined extracts were washed with brine solution and dried over anhydrous MgSO4. Filtration and concentration gave the crude oil (may contain some dimethylformamide) which was diluted with acetonitrile and water. Then, it was frozen and lyophilized over 3 days to isolate 4-oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylic acid (33) (59 mg, 55% yield) as a light brown solid.

Provenance & Evidence