Methyl 2-(2,6-difluorobenzyl)isonicotinate → Methyl 2-(2,6-difluorobenzyl)piperidine-4-carboxylate

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Reaction Steps

Methyl 2-(2,6-difluorobenzyl)isonicotinate (5.031 g, 19.11 mmol) was dissolved in acetic acid (49 mL) and platinum(IV) oxide (0.217 g, 0.96 mmol) was added. The mixture was hydrogenated in a Büchi hydrogenator at room temperature and 5 bar for 5 h. More platinum(IV) oxide (0.108 g, 0.48 mmol) was added and hydrogenation was continued for 1 h. Additional platinum(IV) oxide (0.108 g, 0.48 mmol) was added and the mixture was again hydrogenated for 1.5 h. More platinum(IV) oxide (0.108 g, 0.48 mmol) was added. After a total of 8.5 h the reaction mixture was filtered through celite and the catalyst was washed with MeOH. The eluate was concentrated and DCM and 1 M K2CO3 were added. The phases were separated and the organic phase was washed with brine before it was dried and concentrated to yield methyl 2-(2,6-difluorobenzyl)piperidine-4-carboxylate (5.01 g, 97%). MS m/z 270 (M+H)+

Provenance & Evidence