HCID 67420753, compound → HCID 136053070, compound

Participants

Reaction Steps

A mixture of 3-(2,4-bis-benzyloxy-5-chloro-phenyl)-1,5,6,7-tetrahydro-pyrazolo[4,3-b]pyridine-4-carboxylic acid tert-butyl ester (e) and 3-(2,4-bis-benzyloxy-5-chloro-phenyl)-1,4,5,7-tetrahydro-pyrazolo[3,4-c]pyridine-6-carboxylic acid tert-butyl ester (f) (7 g, 13 mmol) was dissolved in a mixture of ethanol (50 mL) and glacial acetic acid (10 mL) at room temperature before the addition of 10% Pd/C (1 g). The reaction mixture was stirred under hydrogen atmosphere (20 psi) for 10 h. The suspension was filtered through celite and the filtrate was concentrate to small volume and ethylacetate (200 mL) was added. The solution was washed with 1 M NaHCO3 solution, then with brine and dried. The solvent was removed and the crude reaction mixture was carefully chromatographed on silica gel eluting with ethylacetate/methanol 6/1 to provide 3-(5-chloro-2,4-dihydroxy-phenyl)-1,5,6,7-tetrahydro-pyrazolo[4,3-b]pyridine-4-carboxylic acid tert-butyl ester (g) (2.3 g, 48% yield).

Provenance & Evidence