Sodium Hydroxide → ethyl (10R,15S)-3-oxo-1,4,12-triazatetracyclo[7.6.1.05,16.010,15]hexadeca-5,7,9(16)-triene-12-carboxylate

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Reaction Steps

Sodium cyanoborohydride (4.0 g; 65 mmol) was added, in small portions, to a vigorously stirred solution of ethyl 2,3,9,10-tetrahydro-2-oxo-1H-pyrido[3′,4′:4,5]-pyrrolo[1,2,3-de]quinoxaline-8(7H)-carboxylate (11.97 g, 40 mmol) in trifluoroacetic acid (125 mL) cooled in an ice-water bath, under nitrogen. After the addition was complete, the mixture was stirred for 30 min and then poured slowly into ammonium hydroxide (300 mL) containing ice followed by the addition of enough 1N sodium hydroxide to make the mixture basic. The mixture was extracted with dichloromethane (2×) and the extract was washed with water, dried over magnesium sulfate, and evaporated to dryness to yield 10.89 g (90%) of ethyl (6bR,10aS)-2-oxo-2,3,6b,9,10,10a-hexahydro-1H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxaline-8(7H)-carboxylate as an off-white powder, m.p. 167-168° C. (dec., sinters at 70° C.). 1H NMR (CDCl3, 300 MHz) δ 1.28 (t, J=7 Hz, 3H), 1.81-1.95 (m, 2H), 3.13-3.22 (m,1H), 3.23-3.39 (m, 1H), 3.44 (d, J=14.7 Hz, 1H), 3.41-3.51(m, 1H), 3.80-3.95 (m, 1H), 3.98 (d, J=14.7 Hz, 2H), 4.16 (q, 2H), 6.59 (d, J=7.7 Hz, 1H), 6.74 (t, J=7.7 Hz, 1H), 6.83 (d, J=7.7 Hz, 1H), 8.17 (s, 1H) ppm. MS (CI): 302 (M+H+).

Provenance & Evidence