Phosphorus oxychloride → 1-Chloro-6-methoxy-4-methylphthalazine

Participants

Reaction Conditions

Reaction Steps

A solution of 6-methoxy-4-methyl-2H-phthalazin-1-one (6) (2.0 g, 10.5 mmol) in POCl3 (20 mL) is heated at reflux (120° C.) for 4 h and then cooled to room temperature. Unreacted POCl3 is removed at reduced pressure, followed by azeotroping with toluene (2×10 mL). The residue is diluted with sat. NaHCO3 (75 mL) and extracted with dichloromethane (150 mL, 2×60 mL, and 50 mL). The extract is washed (brine) and dried. After solvent removal at reduced pressure, the residue is dried under high vacuum to give 2.2 g (100%) of 7 as a yellow solid, mp 123-126° C. IR 2991, 1611, 1403, 1290, 1234 cm−1; 1H NMR (CDCl3) δ 2.95 (s, 3H, CH3), 4.05 (s, 3H, CH3O), 7.25 (d, J=1.2 Hz, 1H, 5-PhthH), 7.55 (dd, J=6.0, 1.2 Hz, 1H, 7-PhthH), 8.21 ppm (d, J=6.0 Hz, 1H, 8-PhthH).

Provenance & Evidence