A mixture of (2,2-dimethyl-5-oxo-[1,3]dioxolan-4-ylidene)-acetic acid (0.936 g, 5.43 mmol) in dry acetonitrile (10 ml) was treated successively with [1-(4-chlorobenzyl)-2-(4-chlorophenyl)-ethyl]-methylamine (1.60 g, 5.43 mmol), benzotriazole-1-yl-oxy-tris-pyrrolidino-phosphonium hexafluorophosphate (PyBOP®) (3.11 g, 5.98 mmol) and triethylamine (0.83 ml, 5.98 mmol). After 3 h at 22° C., the clear solution was diluted with ethyl acetate, washed with 0.1 N hydrochloric acid, saturated sodium bicarbonate, brine and dried (magnesium sulfate). Evaporation of the solvent and chromatography of the residue on silica gel (elution toluene-ethyl acetate, 7:3) gave 2.35 g (97% yield) of the title amide as white needles; mp 109° C. (ethyl acetate-hexane). 1HNMR 400 MHz (CDCl3) δ (ppm): mixture of rotamers; 1.62 and 1.69 (6H, 2 s, CH3), 2.75 and 2.97 (3H, 2 s, NCH3), 2.8-2.9 (4H, m, CH2), 4.15 (1H, m, CH), 5.44 and 5.89 (1H, 2 s, CH), 7.05-7.3 (8H, m, aromatics). Anal. calcd for C23H23C12NO4: C, 61.62; H, 5.17; N, 3.12. Found: C, 61.39; H, 5.25; N, 3.22.
