2,4-Dichlorophenyl isocyanate → 3-(2,4-Dichlorophenyl)-6-fluoroquinazoline-2,4(1H,3H)-dione

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Reaction Conditions

Reaction Steps

A solution of 2,4-dichlorophenyl isocyanate (18.8 g, 0.10 mol) in N-methylpyrrolidone (50 ml) is metered at room temperature into a solution of ethyl 5-fluoroanthranilate (18.3 g, 0.10 mol) in N-methylpyrrolidone (70 ml). After addition is complete, the mixture is stirred at 90° C. for 2 hours. 1.80 ml of a 30% strength solution of methanolic sodium methoxide (0.010 mol) are metered in and the mixture is stirred under reflux for a further 2 hours, ethanol and methanol being distilled off. After cooling, the product is precipitated by addition of dilute hydrochloric acid (100 ml). The product is then filtered off with suction, washed with water and dried. 29.8 g of 3-(2,4-dichlorophenyl)-6-fluoro-2,4(1H,3H)-quinazolinedione (yield: 91.7% of theory) of melting point 311° to 313° C. are obtained.

Provenance & Evidence