o-Methylvalerolactim → 3-(3,4-Difluorophenyl)-5,6,7,8-tetrahydroimidazo-[1,5-a]pyridine-1-carboxylic acid

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Reaction Conditions

Reaction Steps

6-methoxy-2,3,4,5-tetrahydropyridine (0.431 g, 3.80 mmol) was dissolved in THF (5 mL) in a 40 mL screw-cap vial and 2-(3,4-difluorophenyl)oxazol-5(4H)-one (0.75 g, 3.80 mmol) in THF (5 mL) was added, producing an orange solution. The vial was capped and heated to 90° C. for 3 hours. THF was removed under reduced pressure and the residue was dissolved in MeOH (10 ml) and lithium hydroxide monohydrate (0.479 g, 11.41 mmol) in water (1 mL) was added. The reaction was heated to 90° C. for 3 hours. MeOH was removed by evaporation under reduced pressure. The remaining aqueous solution was diluted with water (5 mL) and acidified to pH 2 with 5M HCl. The solution was extracted with EtOAc (3×5 mL). The combined organic extracts were dried over anhydrous sodium sulfate, filtered and evaporated to yield the desired product as a brown oil (742 mg, 71%) that was used without further purification. LCMS (+ESI) m/z: 279.3 [M+H]+.

Provenance & Evidence