Triethylamine → 6-Quinazolinecarboxylic acid, 1,2,3,4-tetrahydro-5,7-dimethyl-2,4-dioxo-1-(2-(1-piperidinyl)ethyl)-3-(2-(trifluoromethyl)phenyl)-, ethyl ester

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Reaction Steps

Triethylamine (0.58 g) and o-(trifluoromethyl)phenyl isocyanate (0.53 g) were added to a solution of the benzoic acid described above (1.2 g) in diethyl ether (20 ml), and the mixture was refluxed for 4 hours. After evaporating the solvent, the residue was dissolved in ethanol (20 ml) containing 10% hydrogen chloride. The solution was refluxed for one hour and then concentrated. The concentrate was diluted with water and extracted with CHCl3, and the CHCl3 extracts were combined, washed successively with 10% aqueous Na2CO3 solution and brine, and dried over anhydrous Na2SO4. The solvent was evaporated, and the residue was recrystallized from diethyl ether-n-hexane to give 6-ethoxycarbonyl-5,7-dimethyl-1-(2-piperidinoethyl)-3-[2-(trifluoromethyl)phenyl]-2,4(1H,3H)-quinazolinedione (1.1 g, 72%) melting at 144°-145° C. MS: m/e, 517(M+), 498, 472, 433, 406. NMR: δ (ppm. CDCl3), 1.40 (3H, t), 1.50 (6H, b), 2.45 (3H, s), 2.52 (6H, t), 2.70 (3H, s), 4.30 (2H, t), 4.45 (2H, q), 7.10-7.80 (5H, m).

Provenance & Evidence