N-methyl-2-pyrrolidone → 1-(((5S,7S)-3-(5-ethoxypyrazin-2-yl)-7-methyl-2-oxo-1-oxa-3-azaspiro[4.5]decan-7-yl)methyl)-1H-benzo[d]imidazole-6-carbonitrile

Participants

Reaction Steps

To a 10 mL flask was added NMP (7.11 mL), ethyl (5-ethoxypyrazin-2-yl)carbamate (0.863 g, 4.09 mmol) and potassium tert-butoxide (0.399 g, 3.55 mmol) at RT. After stirring for ˜5 min at RT, 1-{[(3S,5S)-5-methyl-1-oxaspiro[2.5]oct-5-yl]methyl}-1H-benzimidazole-6-carbonitrile (1 g, 3.55 mmol) was added. The solution was then heated to 70° C. (oil bath) and stirred for 7 h. At 7 h, the temperature was taken to 80° C., then at 8 h, it was taken to 90° C. The mixture was allowed to stir at 90° C. for 16 h. The resulting solution was cooled to RT and added dropwise to a 50 mL solution of IPA/Water (1:1) that contained a small crystalline seed. The mixture was allowed to stir at RT overnight. The next day, the slurry was filtered, and the solids slurried in MeCN overnight. The next day, the solids were filtered off, dried under reduced pressure to give 1-(((5S,7S)-3-(5-ethoxypyrazin-2-yl)-7-methyl-2-oxo-1-oxa-3-azaspiro[4.5]decan-7-yl)methyl)-1H-benzo[d]imidazole-6-carbonitrile as a very light yellow solid (968 mg, 61% yield). 1H NMR (400 MHz, DMSO-d6) δ 8.80 (d, J=1.25 Hz, 1H), 8.48 (s, 1H), 8.38 (s, 1H), 8.10 (d, J=1.51 Hz, 1H), 7.83 (d, J=8.53 Hz, 1H), 7.59 (dd, J=1.25, 8.28 Hz, 1H), 4.32 (q, J=7.03 Hz, 2H), 4.16 (s, 2H), 3.80-3.88 (m, 2H), 1.98 (d, J=13.80 Hz, 1H), 1.88 (d, J=14.31 Hz, 1H), 1.64-1.73 (m, 3H), 1.49-1.53 (m, 2H), 1.34-1.38 (m, 2H), 1.32-1.38 (t, J=8.0 Hz, 2H), 1.07 (s, 3H). MS (m/z) 447.2 (M+H+).

Provenance & Evidence