p-Toluenesulfonic acid monohydrate → HCID 57535334, compound

Participants

Reaction Steps

A solution of 5-Benzyloxycarbonylamino-2-isopropyl-3-oxo-hexanedioic acid 1-tert-butyl ester 6-methyl ester (1.06 g, 2.51 mmol) and p-toluenesulfonic acid monohydrate (35.8 mg, 0.19 mmol) in toluene (20 mL) is heated to reflux under N2 for 6.5 hr. The mixture is cooled to room temperature, and concentrated in vacuum. The residue is purified over 35 g silica gel, eluting with EtOAc:Heptane (1:4) to afford (S)-2-Benzyloxycarbonylamino-6-methyl-4-oxo-heptanoic acid methyl ester (727 mg, 90%). 1H NMR (CDCl3): δ 7.4 (m, 5H), 5.78 (d, J=9.1 Hz, 1H), 5.13 (s, 2H), 4.6 (m, 1H), 3.74 (s, 3H), 3.2 (dd, J=18.3, 4.4 Hz, 1H), 2.95 (dd, J=18.2, 4.0 Hz, 1H), 2.3 (m, 2H), 2.1 (m, 1H), 0.92 (d, J=6.7 Hz, 6H); LC/MS: 77% 322 (MH+).

Provenance & Evidence