2-(Trifluoromethyl)phenyl isocyanate → 6-ethoxycarbonyl-5,7-dimethyl-3-[2-(trifluoromethyl)phenyl]-2,4-(1H,3H)-quinazolinedione

Participants

Reaction Steps

α,α,α-Trifluoro-o-tolyl isocyanate (434 mg) was added to a solution of 2-amino-5-ethoxycarbonyl-4,6-dimethylbenzoic acid (500 mg) in diethyl ether (22 ml), and the mixture was stirred overnight. The resulting precipitate was filtered off and dissolved in ethanol (15 ml). Then, hydrogen chloride (1 g) was introduced into the solution. The reaction mixture was refluxed for 3 hours and the solvent was evaporated off. The residue was recrystallized from diethyl ether to give 6-ethoxycarbonyl-5,7-dimethyl-3-[2-(trifluoromethyl)phenyl]-2,4-(1H,3H)-quinazolinedione (575 mg, 67%) melting at 175°-176° C. MS: m/e, 406(M+), 377, 361, 357, 337, 332, 314, 309. NMR: δ(ppm, CDCl3) 1.40 (3H, t), 2.30 (3H, s), 2.68 (3H, s), 4.44 (2H, q), 6.70 (1H, b), 7.2-8.0 (4H, m), 10.25 (1H, s).

Provenance & Evidence