Trifluoroacetic acid → 7-(piperazin-1-yl)-3,4-dihydroquinazolin-2(1H)-one

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Reaction Steps

To a solution of 16 (0.7 g, 2.11 mmol) in a mixture of CH2Cl2 (15 mL) and THF (5 mL) at 0° C. was added TFA (5 mL) and the mixture was stirred at room temperature for 6 h. The solvent was evaporated under vacuum to afford 0.66 g (96%) of compound 5 as a dark brown gum. IR (KBr) νmax. cm−1: 3261 (NH), 3032 (Ar—H), 1691 (C═O), 1613, 1513, 1415 (C═C). 1H NMR (500 MHz, DMSO-d6) δ=3.18 (m, 4H, 2CH2); 3.42 (m, 4H, 2CH2); 4.23 (s, 2H, CH2); 6.66 (m, 2H, aromatic-H); 6.73 (m, 1H, aromatic-H); 8.80 (br. s, 1H, NH); 8.86 (br. s, 1H, NH); 13C NMR (125.7 MHz, DMSO-d6) δ=46.35 (CH2), 46.73 (CH2), 48.63 (CH2), 114.19 (aromatic-C), 114.38 (aromatic-C), 116.49 (aromatic-C), 118.83 (aromatic-C), 131.87 (aromatic-C), 144.81 (aromatic-C), 154.72 (C═O). Calculated (%) for C14H16F3N4O2 (329.12); C, 48.56; H, 4.95; N, 16.18. found (%); C, 48.45; H, 5.05; N, 16.15.

Provenance & Evidence