Reaction Steps
A solution of 3-(4-piperidinyl)-5-(4-chlorophenyl)pyrazole (1.50 g), triethylamine (1.60 cm3) and 4-chlorobenzyl chloride (0.92 g) in 3:1 dichloromethane-dimethylformamide (20 cm3) was stirred at room temperature for 4.5 hours. Dichloromethane was removed by evaporation and the crude product was partitioned between water (25 cm3) and ethyl acetate (2×25 cm3). The combined organic extracts were washed with saturated brine (20 cm3), dried (MgSO4), filtered and evaporated to dryness to give an off-white solid. Recrystallisation from ethanol-water yielded the title compound as fine, white needles (0.575 g, 26%), m.p. 179°-181° C. (from EtOH/H2O); (Found: C, 65.19; H, 5.24; N, 10.86. C21H21N3Cl2 requires C, 65.29; H, 5.48; N, 10.88%.); δH (360 MHz; CDCl3) 1.71 (2H, apparent qd, J=12 and 3, 2×NCH2CHAHB), 1.84 (2H, apparent d, J=11, 2×NCH2CHAHB), 1.92 (2H, apparent t, J=11, 2×NCHAHB), 2.41-2.55 (1H, m, NCH2CH2CH), 2.84 (2H, apparent d, J=11, 2×NCHAHB), 3.44 (2H, s, NCH2Ar), 6.21 (1H, s, N=C--CH=C), 7.30-7.21 (6H, m, 6×ArH), 7.61 (2H, d J=8.1, 2×ArH) and 11.6-12.0 (1H, br s, NH); δC (90 MHz; CDCl3) 31.9 (t), 33.8 (d), 53.3 (t), 62.5 (t), 99.5 (d), 126.9 (d), 128.6 (d), 128.9 (d), 130.3 (d), 132.8 (s), 133.5 (s) and 136.8 (s). 3 quaternary carbons not observed; m/z (CI+ ; NH3) 386 (M+ +H; 30%), 262 (22), 228 (18), 210 (10), 196 (17), 179 (28), 162 (28), 154 (40), 142 (67), and 140 (100); m/z (CI- ; NH3) 420 (M- +Cl; 2%); 385 (M- ; 10), 259 (10), 178 (27) and 127 (20).
