Water → 2-[(1R)-1-aminoethyl]-1-(4-methylphenyl)sulfonylpyrrole-3-carboxylic acid;2,2,2-trifluoroacetic acid

Participants

Reaction Steps

To a solution of (R)-tert-butyl 2-(1-((tert-butoxycarbonyl)amino)ethyl)-1-tosyl-1H-pyrrole-3-carboxylate (702c; 25.11 g, 54.0 mmol) in 120 mL DCM was added TFA (Aldrich; 120 mL, 1621 mmol) slowly in portions (Caution: gas evolution was observed). After complete addition, the dark brown reaction was stirred 5 min, was fitted with a water-cooled reflux condenser and drying tube and was placed in a pre-heated 50° C. oil bath. The reaction was heated at reflux for 3 h; gas evolution was mild. The reaction was cooled and concentrated in vacuo and the solid material was dried in vacuo for 48 h to give (R)-2-(1-aminoethyl)-1-tosyl-1H-pyrrole-3-carboxylic acid compound with 2,2,2-trifluoroacetic acid (1:1) (22.83 g, 54.1 mmol, 100% yield). 1H NMR (400 MHz, MeOH-d4) d ppm 7.89 (2H, d, J=8.4 Hz), 7.57 (1H, d, J=3.5 Hz), 7.52 (2H, d, J=8.2 Hz), 6.79 (1H, d, J=3.5 Hz), 5.28 (1H, q, J=6.8 Hz), 2.47 (3H, s), 1.32 (3H, d, J=6.8 Hz). m/z (ESI, +ve) 309.0 (M+H)+.

Provenance & Evidence