Acetic Anhydride → 1-acetyl-2-(2-chlorophenyl)-4-methyl-5-(pyridin-2-ylmethyl)-1H-pyrazolo[4,3-c]pyridine-3,6(2H,5H)-dione

Participants

Reaction Conditions

Reaction Steps

10.0 ml of acetic anhydride was added to a mixture of 2-(2-chlorophenyl)-4-methyl-5-(pyridin-2-ylmethyl)-1H-pyrazolo[4,3-c]pyridine-3,6(2H,5H)-dione (Compound of Formula (Ia) (0.250 g, 0.682 mmol, 1 equiv.) and sodium acetate (0.056 g, 0.682 mmol, 1 equiv). The resulting mixture was heated at 40° C. for 1 h and then concentrated in vacuo. The resulting residue was dissolved in EtOAc and washed with water. The organic phase was dried over Na2SO4 and concentrated in vacuo until dryness to afford 0.228 g of the desired compound 1-acetyl-2-(2-chlorophenyl)-4-methyl-5-(pyridin-2-ylmethyl)-1H-pyrazolo[4,3-c]pyridine-3,6(2H,5H)-dione as a white solid (82% yield). Rf (EtOAc) 0.34; 1H NMR (500 MHz, CDCl3) 2.08 (s, 3H), 2.95 (s, 3H), 5.47 (s, 2H), 7.04 (s, 1H), 7.21 (m, 1H), 7.37-7.32 (m, 4H), 7.56 (m, 1H), 7.67 (td, J 7.6, 1.9 Hz, 1H), 8.51 (m, 1H); MS (ESI+): 409.2; MS (ESI−): 407.7.

Provenance & Evidence