Dichloromethane → Trifluoroacetic acid

Participants

Reaction Steps

tert-Butyl (R)-4-((R)-3-(7-chloro-1-(3-methoxypropyl)-1H-benzo[d]imidazol-2-yl)piperidin-1-yl)-1-(naphthalen-2-yl)-4-oxobutan-2-ylcarbamate (0.111 mmol max, crude oil from Step F) was added to a 10 mL round-bottomed flask equipped for stirring under nitrogen. Dichloromethane (1 mL) and trifluoroacetic acid (1 mL) were then added and the resultant solution was allowed to stir under nitrogen for 4 HR. The solvent was removed in-vacuo affording a clear colored oil. This oil was re-dissolved in methanol (3 mL), filtered, and then purified by preparative LC/MS (25-65% CH3CN in H2O). The resultant fractions were collected and the solvent was removed in-vacuo affording a clear colored oil. This oil was re-dissolved in CH3CN (1 mL) and water (2 mL). The resultant solution was frozen and lyophilized to afford (R)-3-amino-1-((R)-3-(7-chloro-1-(3-methoxypropyl)-1H-benzo[d]imidazol-2-yl)piperidin-1-yl)-4-(naphthalen-2-yl)butan-1-one (97) as its trifluoroacetic acid salt as a white flocculent solid (0.052 mmol, 0.033 g, 47% over 3-steps) 1H NMR (400 MHz, DMSO-d6) δ ppm 1.35-1.56 (m, 1H) 1.63-2.14 (m, 5H) 2.60-2.78 (m, 2H) 2.88-3.42 (m, 9H) 3.69-4.01 (m, 3H) 4.00-4.61 (m, 5H) 7.10-7.30 (m, 2H) 7.42-7.60 (m, 4H) 7.73-7.99 (m, 4H) ESI-MS: m/z 519.2 (M+H)+.

Provenance & Evidence