Trifluoromethanesulfonic acid → HCID 86751018, compound

Participants

Reaction Steps

7.1 ml (80.74 mmol) of trifluoromethanesulphonic acid were added dropwise under argon and while cooling with ice to a suspension of 7.5 g (13.54 mmol) of N2 -[(S)-2-benzamido-8-methoxy-1,2,3,4-tetrahydro-naphthalene-2-carbonyl]-L-phenylalanine cyclohexylamide in 35 ml of methanol. The mixture was stirred at 80° in a bomb tube for 4 hours, then cooled and subsequently concentrated to a volume of ~20 ml. 50 ml of dichloromethane were added while stirring, the suspension was filtered and the filter residue was washed with dichloromethane and dried, 4.48 g (83%) of L-phenylalanine cyclohexylamide trifluoromethanesulphonate being isolated. The filtrate was washed with water, dried over MgSO4 and concentrated. The residue was chromatographed on 350 g of silica gel with ethyl acetate/hexane (2:3), whereupon 4.0 g (87%) of methyl (S)-2-benzamido-8-methoxy-1,2,3,4-tetrahydro-naphthalene-2-carboxylate were obtained. [α]D =+144.0° (CHCl3, c=0.2). IR(KBr): 3366w(br.), 3062w, 2998w, 2948w, 1739s, 1647s, 1586m, 1527s, 1468s, 1437m, 1292m, 1259s, 1099m, 1047m, 774w, 713m. (D. Obrecht, Helv. Chim. Acta 1992, 75, 1666).

Provenance & Evidence