2-Chlorobenzoxazole → methyl (2S)-1-(1,3-benzoxazol-2-yl)-2-piperidinecarboxylate

Participants

Reaction Steps

N-Ethyldiisopropylamine (6.52 ml) was added to a solution of (2S)-2-(methoxycarbonyl)piperidinium chloride (3.057 g) [see Preparation 1] and 2-chlorobenzoxazole (2.13 ml) in acetonitrile (50 ml). The reaction mixture was stirred at room temperature for 18 hours and then at 50° C. for a further 2 hours. The solvent was removed under reduced pressure and the residue partitioned between ethyl acetate and water, the organic layer was separated, dried over magnesium sulphate and the solvent removed under reduced pressure. The crude product was purified by column chromatography on silica gel eluting with a solvent gradient of 80:10:0, changing to 0:100:0, followed by 0:95:5, by volume, hexane:ethyl acetate:methanol, to afford methyl (2S)-1-(1,3-benzoxazol-2-yl)-2-piperidinecarboxylate (3.18 g) as a solid.

Provenance & Evidence