Methanol → Methyl 3-(1-chlorophthalazin-6-yl)-4-methylbenzoate

Participants

Reaction Conditions

Reaction Steps

In a 500 mL RBF was added methanol (200 mL, 54 mmol) followed by oxalyl chloride (5.0 ml, 54 mmol) drop wise while cooling with an ice bath. It was stirred for 5 min. and 3-(1-hydroxyphthalazin-6-yl)-4-methylbenzoic acid (15.00 g, 54 mmol) was then added in portions over 2 min. The reaction was fitted with a reflux condenser and heated to 85° C. in an oil bath for 2 h. The reaction mixture was concentrated on the rotovap then under high vacuum overnight. The resulting white fluffy solid in 260 mL of anhydrous CH3CN was treated with POCl3 (9.9 mL, 107 mmol), and heated to 70° C. in an oil bath for 4 h. The reaction mixture was cooled to RT and filtered through a sintered glass frit to remove the suspended solid, and rinsed with 50 mL of CH3CN. The filtrate was concentrated to give a yellow oil. The oil was dissolved in 250 mL CH2Cl2, washed with a saturated solution of NaHCO3 followed by brine. The organic solution was dried over MgSO4, filtered and concentrated to give methyl 3-(1-chlorophthalazin-6-yl)-4-methylbenzoate (14.54 g, 87% yield) as a tan crystalline. This crude material was used in the next step without further purification. MS (ESI, pos. ion) m/z: 313.1 (M+1).

Provenance & Evidence