Malononitrile → 4-amino-6,7,8,9-tetrahydro-2-(1H-indazol-5-yl)-2H-quinolizine-1,3-dicarbonitrile

Participants

Reaction Steps

To a mixture of 1H-indazole-5-carboxaldehyde (200 mg, 1.37 mmol), from Synthetic Preparation 1, and malononitrile (100 mg, 1.51 mmol) in EtOH (5 mL) was added piperidine (0.2 mL). The mixture was stirred at rt for 2 hr, after which the solid (140 mg) was collected by filtration. This solid and 2-piperidinylidene-ethanenitrile (100 mg, 0.82 mmol; per Synthetic Preparation 5) were combined in EtOH (5 mL). The resulting mixture was kept at 90° C. for 1 hr. After cooling to rt, the solvent was removed in vacuo. The residue was purified on flash column (silica gel) and crystallized further in acetate to afford 4-amino-6,7,8,9-tetrahydro-2-(1H-indazol-5-yl)-2H-quinolizine-1,3-dicarbonitrile (110 mg, 25.4%) (Cpd. No. 305). 1H-NMR (400 MHz, CD3OD): δ=8.02 (s, 1H), 7.58 (s, 1H), 7.53 (d, 1H), 7.34 (d, 1H), 4.53 (s, 1H), 3.63 (d, 2H), 2.72 (m, 2H), 1.95 (m, 1H), 1.73-1.88 (m, 3H) ppm.

Provenance & Evidence