Acetaldehyde → (1R,2R)-N1-[3,6-dicyclopropyl-5-(2,4-dichlorophenyl)pyrazin-2-yl]-N2-ethyl-2,3-dihydro-1H-indene-1,2-diamine

Participants

Reaction Steps

To a solution of (1R,2R)-N1-[3,6-dicyclopropyl-5-(2,4-dichlorophenyl)pyrazin-2-yl]-2,3-dihydro-1H-indene-1,2-diamine (0.15 g, 0.33 mmol) in MeOH (3.3 mL) was sequentially added acetaldehyde (22 mg, 0.5 mmol) and AcOH (5 drops). This mixture was stirred for 30 min before addition of NaBH3CN (1 M solution in THF, 0.6 mL, 0.6 mmol). Stir at rt overnight. Add additional acetic acid (2 drops), acetaldehyde (29 μL, 0.5 mmol) and NaBH3CN (1 M solution in THF, 0.6 mL, 0.6 mmol). After 2 hr, add additional acetic acid (2 drops), acetaldehyde (29 μL, 0.5 mmol) and NaBH3CN (1 M solution in THF, 0.6 mL, 0.6 mmol). After 3 hr, dilute mixture with EtOAc and wash with sat. aq. NaHCO3 and extract with EtOAc (3×40 mL). The combined organic extracts were dried over MgSO4, filtered and concentrated. Purify by biotage MPLC (90 g column, 100% ethyl acetate) to afford 0.16 g (44%) of (1R,2R)-N1-[3,6-dicyclopropyl-5-(2,4-dichlorophenyl)pyrazin-2-yl]-N2-ethyl-2,3-dihydro-1H-indene-1,2-diamine as a solid: 1H NMR (CDCl3) δ 0.84–1.05, 1.62–1.75, 2.78–2.86, 3.31–3.37, 3.52, 5.22, 5.52, 7.28–7.51; MS (ESI+) for C27H28Cl2N4 m/z 479 (M+H)+.

Provenance & Evidence