Reaction Steps
A solution of 7-(2,4-dichlorophenyl)-2-ethyl-N,N-dipropylpyrazolo[1,5-a]pyridin-3-amine (530 mg, 1.4 mmol) in ethyl acetate (20 mL) was treated with maleic acid (169 mg, 1.4 mmol) dissolved in CH3OH (1.5 mL). The solution was stirred at room temperature for 1.5 hours then concentrated in vacuo to give a yellow oil. Trituration with Et2O and hexane gave 560 mg (81%) of a brown solid as the title compound: mp 106–112° C.; 1H NMR (400 MHz, DMSO-d6) δ 7.82 (d, J=1.9 Hz, 1H), 7.68–7.57 (m, 3H), 7.20–7.16 (m, 1H), 6.78 (d, J=6.4 Hz, 1H), 6.26 (s, 1H), 3.03 (t, J=7.0 Hz, 4H), 2.65 (q, J=7.5 Hz, 2H), 1.36–1.27 (m, 4H), 1.13 (t, J=7.5 Hz, 3H), 0.85 (t, J=7.3 Hz, 6H); 13C NMR (100 MHz, DMSO-d6) δ 166.6, 153.2, 136.3, 135.9, 134.6, 134.4, 133.2, 131.8, 130.5, 128.9, 127.4, 121.9, 116.6, 112.5, 57.4, 21.2, 19.0, 13.9, 11.4; IR (diffuse reflectance) 2975, 2965, 2940, 2491, 2353, 2335, 1983, 1948, 1586, 1552, 1547, 1485, 1470, 1455, 1354 cm−1; HRMS (FAB) calcd for C21H25Cl2N3+H 390.1504. found 390.1501; Anal. Calcd for C21H25Cl2N3.C4H4O4: C, 59.29; H, 5.77; N, 8.30. Found: C, 59.40; H, 5.78; N, 8.14.
