Trifluoroacetic acid → ethyl 6-[(ethoxycarbonyl)amino]-1,3,4,4a,5,9b-hexahydro-2H-pyrido[4,3-b]indole-2-carboxylate

To a solution of ethyl 6-[(ethoxycarbonyl)amino]-1,3,4,5-tetrahydro-2H-pyrido[4,3-b] indole-2-carboxylate (4.5 g, 13.6 mmol) in CH2Cl2 (40 mL) at 0° C. was added TFA (20 mL) followed by NaCNBH3 (1.8 g, 27 mmol) and stirred at rt for 3 hours before the solvent was removed by the nitrogen stream. To the resulting residue were added CH2Cl2 (40 mL) and 6N HCl (20 mL) and stirred for 0.5 hour. The solution was diluted with water (20 mL), 1N NaOH (30 mL) and extracted with CH2Cl2 (2×30 mL). The combined extracts were dried over magnesium sulfate, concentrated, and purified by flash chromatography to afford ethyl 6-[(ethoxycarbonyl)amino]-1,3,4,4a,5,9b-hexahydro-2H-pyrido[4,3-b]indole-2-carboxylate (3.6 g, 80%) as a clear oil. MS [M+H]+334. 1H NMR (CDCl3, 300 MHz): δ 6.97 (d, 1H, J=7.3 Hz), 6.85 (d, 1H, J=7.3 Hz), 6.72 (t, 1H, J=7.3 Hz), 4.05 (m, 4H), 3.41 (m, 4H), 1.92 (m, 2H), 1.20-1.24 (m, 6H) ppm.

1. customwas removed by the nitrogen stream
2. additionTo the resulting residue were added CH2Cl2 (40 mL) and 6N HCl (20 mL)
3. stirringstirred for 0.5 hour
4. additionThe solution was diluted with water (20 mL), 1N NaOH (30 mL)
5. extractionextracted with CH2Cl2 (2×30 mL)
6. dry with materialThe combined extracts were dried over magnesium sulfate
7. concentrationconcentrated
8. custompurified by flash chromatography

ORD record

ord-1ada7f4f9e084689ba174e95983b544c

Source dataset

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

USRE039680E1