Acetone → 4-Chloro-1-methyl-6-(prop-2-ynyloxy)phthalazine

Participants

Reaction Conditions

Reaction Steps

The mixture of 4-chloro-6-hydroxy-1-methylphthalazine (5) (195 mg, 1.00 mmol), 80% propargyl bromide (1.30 mmol) in toluene (145 μL), K2CO3 (187 mg, 1.35 mmol), and acetone (8 mL) is stirred at 68° C. under argon for 23 h, then cooled to room temperature, and concentrated. The residue is diluted with H2O (50 mL) and extracted with ethyl acetate (70 mL and 60 mL). The extract is washed (brine) and dried. After solvent removal at reduced pressure, the residue is purified on silica gel (33% to 50% ethyl acetate/hexane) to give 129 mg (55%) of 6 as a light-yellow solid, mp 169-171° C. IR 3077, 1401, 1217 cm−1; 1H NMR (CDCl3) δ 2.66 (t, J=2.4 Hz, 1H, C≡CH), 2.97 (s, 3H, CH3), 4.96 (d, J=2.4 Hz, 2H, CH2C≡CH), 7.62 (dd, J=9.3, 2.7 Hz, 1H, 7-PhthH), 7.69 (d, J=2.7 Hz, 1H, 5-PhthH), 8.05 ppm (d, J=9.3 Hz, 1H, 8-PhthH).

Provenance & Evidence