Dichloromethane → Trifluoroacetic acid

Participants

Reaction Steps

tert-Butyl (R)-4-((R)-3-(6-chloro-1-(3-methoxypropyl)-1H-benzo[d]imidazol-2-yl)piperidin-1-yl)-1-(naphthalen-2-yl)-4-oxobutan-2-ylcarbamate (32E) (0.135 mmol max, crude oil) 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 (15-55% 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-(6-chloro-1-(3-methoxypropyl)-1H-benzo[d]imidazol-2-yl)piperidin-1-yl)-4-(naphthalen-2-yl)butan-1-one (99) as its trifluoroacetic acid salt and as a white flocculent solid (0.074 mmol, 0.047 g, 55% yield over 3-steps). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.33-1.54 (m, 1H) 1.68-2.11 (m, 5H) 2.61-2.77 (m, 3H) 2.88-3.44 (m, 9H) 3.71-4.04 (m, 2H) 4.07-4.23 (m, 1H) 4.25-4.39 (m, 1H) 4.49 (dd, J=36.51, 13.26 Hz, 1H) 7.21-7.31 (m, 1H) 7.44 (ddd, J=8.40, 4.61, 1.64 Hz, 1H) 7.47-7.56 (m, 2H) 7.61 (dd, J=17.43, 8.59 Hz, 1H) 7.71-8.06 (m, 5H). ESI-MS: m/z 519.4 (M+H)+,

Provenance & Evidence