Methanol → tert-butyl (8S,9aR)-8-[(5-cyclopropylpyrazin-2-yl)oxy]-5-oxohexahydro-1H-pyrrolo[1,2-a][1,4]diazepine-2(3H)-carboxylate

Participants

Reaction Steps

tert-Butyl (8S,9aR)-8-hydroxy-5-oxohexahydro-1H-pyrrolo[1,2-a][1,4]diazepine-2(3H)-carboxylate (55 mg, 0.203 mmol, Part F) was dissolved in tetrahydrofuran (1.2 mL). Potassium tert-butoxide (0.400 mL, 0.400 mmol, 1.0 M in tetrahydrofuran, 2.0 equivalents) was added at room temperature, and the resulting solution was stirred for five minutes. Then 2-bromo-5-cyclopropylpyrazine (81 mg, 0.407 mmol, 2.0 equivalents) was added as a solution in tetrahydrofuran (0.5 mL). The reaction was allowed to stir at room temperature for 16 hours, at which point it was quenched with 3 drops of saturated sodium bicarbonate. The mixture was concentrated in vacuo, and the residue was loaded onto a 12 g silica column eluted with 100:0 to 95:5 dichloromethane:methanol over 20 minutes to give the titled compound (41 mg, 52% yield) as a white solid. 1H NMR (300 MHz, CDCl3) δ ppm 8.02 (d, J=1.0 Hz, 1H), 7.93 (d, J=1.4 Hz, 1H), 5.44 (t, J=4.0 Hz, 1H), 4.45-4.17 (br s, 2H), 4.07-3.98 (m, 2H), 3.67 (dd, J=13.8, 4.1 Hz, 1H), 3.00 (br s, 1H), 2.73-2.66 (m, 3H), 2.49 (dd, J=12.0, 7.6 Hz, 1H), 2.01-1.82 (m, 2H), 1.48 (s, 9H), 1.02-0.89 (m, 4H); MS (ESI+) m/z 333.0 (M-tBu+H)+.

Provenance & Evidence