p-Toluenesulfonic acid → HCID 53785033, compound

Participants

Reaction Steps

In benzene (100 ml) was dissolved tert-butyl (S)-2-(N-benzyloxycarbonylamino)-5-hydroxyvalerate [synthesized by the method described in the Journal of Organic Chemistry, 55, 1711 (1990)](5.1 g) and following addition of p-toluenesulfonic acid (0.05 g), the mixture was stirred under reflux for 1 hour. This reaction mixture was diluted with ethyl acetate (100 ml) and washed with water, saturated aqueous sodium hydrogen carbonate and saturated aqueous sodium chloride in the order mentioned. After drying (MgSO4), the solvent was distilled off. The residue was chromatographed on a silica gel column and elution was carried out with ethyl acetate-hexane (1:2, v/v). From the eluate was obtained (S)-3-(N-benzyloxycarbonylamino)-2-oxotetrahydropyran (2.0 g, 51%) as an oil. NMR (δ ppm in CDCl3): 1.54-1.74 (1H, m), 1.96-2.10 (2H, m), 2.55-2.72 (1H, m), 4.36 (2H, t, J=6.2 Hz), 4.37-4.50 (1H, m), 5.13 (2H, s), 5.62 (1H, broad), 7.34-7.40 (5H, m). Optical rotation [α]D +51.5° (C=0.98, CHCl3)

Provenance & Evidence