Dichloromethane → 3-[2(R)-Amino-3-mercaptopropyl-amino]N-(2,3-dimethylphenyl)benzamide dihydrochloride

To a solution of 3 (0.410 g ) in 10 mL of methylene chloride was added triethylsilane (0.200 g ) and 5 mL of trifluoroacetic acid. The solution was stirred for 45 min, evaporated in vacuo, and partitioned with hexane and 0.1% trifluoroacetic acid in water:methanol 2:1. The 0.1% trifluoroacetic acid/water: methanol solution was injected directly onto a Delta-Pak (C-18, 100 Å, 15 mm, 40mm×100mm) prep HPLC column. The gradient at 40 mL/min. was 100%A (0.1% trifluoroacetic acid/water) for 5 min. followed by 85% A to 50%A in 60 min. with B as 0.1% trifluoroacetic acid/acetonitrile. The pure fractions were pooled, evaporated in vacuo to near dryness, and then taken up in 5 mL of water. This water solution was passed through a 1.2 g column of Bio-Rad AG 3-X4 chloride anion exchange resin with water rinses. The resulting aqueous column eluant was lyophillized 20 h to yield the title compound as a solid. NMR (300 MHz, CD3OD)δ 7.30 (3H, m), 7.12 (3H, s), 6.97 (1H, m), 3.30 (3H, m), 2.90 (2H, m ), 2.30 (3H,s), 2.18 (3H, s).