p-Toluenesulfonic acid → HCID 68607104, compound

Participants

Reaction Steps

A suspension of methyl β-[(2-aminophenyl)thio]-N-[(benzyloxy)carbonyl]-2,5-difluorophenylalaninate (4:1, Z:E) (4.3 g) and p-toluenesulfonic acid (catalytic) in xylenes (100 mL) was heated to reflux for 2 h, using a Dean-Stark apparatus to remove water. The mixture was then cooled, resulting in precipitation of the crude product as a white solid (3.3 g, 4:1, cis:trans). This was recrystallized from ethyl acetate/ether to afford the title compound (2.4 g, 60%). 1H NMR (300 MHz, d6-DMSO) δ 4.63 (t, 1H), 4.96 (s, 2H), 5.47 (d, 1H), 7.00 (d, 1H), 7.23-7.34 (m, 9H), 7.49-7.53 (m, 2H), 7.70 (d, 1H), 10.57 (s, 1H). MS APCI, m/z=441 (M+1). LC/MS: 2.74 min.

Provenance & Evidence