313369-26-5

313369-25-4

313369-26-5

Step CA: Under nitrogen protection, borane tetrahydrofuran solution (1 M, 33 mL, 33 mmol) was slowly added dropwise to a stirred solution of (6bR,10aS)-3-methyl-2-oxo-2,3,6b,7,10,10a-hexahydro-1H-pyrido[3',4':4,5]pyrrolo[1,2,3-de]quinoxaline-8(9H)-carboxylic acid tertiary butyl ester (5.24 g, 16.6 mmol) in a solution of anhydrous tetrahydrofuran (25 mL). After dropwise addition, the reaction mixture was heated to reflux for 1 hour. After cooling, 6N hydrochloric acid (15 mL) was added and heating was continued under reflux conditions for 30 minutes. Upon completion of the reaction, the mixture was cooled and evaporated to dryness under reduced pressure. The residue was dissolved in a minimal amount of water, alkalized with 1N sodium hydroxide solution and extracted with dichloromethane (2×). The organic phases were combined, washed with water, dried over magnesium sulfate, and concentrated to give 4.65 g (93% yield) of tert-butyl (6bR,10aS)-3-methyl-2,3,6b,7,10,10a-hexahydro-1H-pyrido[3',4':4,5]pyrrolo[1,2,3-de]quinoxaline-8(9H)-carboxylate as a viscous liquid.1H NMR ( CDCl3, 300MHz) δ 1.28 (t, J = 7Hz, 3H), 1.68-1.78 (m, 1H), 1.78-1.93 (m, 2H), 2.81-2.90 (m, 2H), 2.86 (s, 3H), 3.05-3.26 (m, 2H), 3.26-3.38 (m, 2H), 3.56- 3.75 (m, 2H), 3.79-3.87 (m, 1H), 4.16 (q, J = 7 Hz, 2H), 6.41 (d, J = 8.1 Hz, 1H), 6.61 (d, J = 8.1 Hz, 1H), 6.67 (t, J = 8.1 Hz, 1H) ppm. MS (CI): 302 (M + H+).