Acetic Acid → 7-(2,4-Dichloro-phenyl)-3-ethyl-2-methyl-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridine

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Reaction Steps

To a solution of 7-(2,4-dichloro-phenyl)-2-methyl-3-vinyl-4,5,6,7-tetrahydro-2H-pyrazolo[3,4-b]pyridine (3-7; 0.046 g, 0.15 mmol) in 2 mL of methanol was added dipotassium azodicarboxylate (0.174 g, 0.90 mmol) [prepared according to D. J. Pasto and R. J. Taylor, Organic Reactions 1991 40:91]. To the yellow suspension was added acetic acid (0.102 mL, 1.80 mmol) in 2 mL of methanol over 40 minutes. The reaction mixture was again treated with dipotassium azodicarboxylate (0.087 g, 0.45 mmol) and then acetic acid (0.051 mL, 0.90 mmol) in 1 mL of methanol over 20 nm. After 3 h at room temperature, the solvent was evaporated, the residue was treated with 10 mL of saturated sodium bicarbonate solution, extracted three times with 25 mL portions of dichloromethane, dried over magnesium sulfate, and evaporated to afford 41 mg of crude product. The crude product was purified by silica gel column chromatography eluting with 0 to 15% ethyl acetate/hexane which afforded 30 mg (65% theory) of 4-6 as a colorless oil: ms (M+H)+=310.

Provenance & Evidence