A solution [[2-(2,2-dimethyl-5-oxo-[1,3]-dioxolan-4-ylidene)-acetyl]-(4-fluorobenzyl)-aminooxy]-acetic acid (0.681 g, 1.93 mmol) in dichloromethane (20 ml) was treated at 22° C. with oxalyl chloride (0.34 ml, 3.9 mmol) and a trace of N,N-dimethylformamide and the resulting mixture was stirred for 1 h. The solvent and excess reagent were then evaporated in vacuo. The residual material was dissolved in dry dichloromethane (10 ml) and added dropwise to a cold (0° C.) solution of dimethylamine (0.18 g, 4.0 mmol) and pyridine (0.25 ml, 3.2 mmol ) in dichloromethane. After 2 h, the reaction mixture was diluted with ethyl acetate, washed with saturated sodium bicarbonate and brine and dried over anhydrous magnesium sulphate. Evaporation of the solvent in vacuo and crystallisation of the residue from a mixture of ethyl acetate and hexane gave 0.370 g (50% yield) of the title material as a white solid. 1HNMR 400 MHz (CDCl3) δ (ppm): 1.77 (6H, s, CH3), 2.91 (3H, s, CH3), 2.97 (3H, s, CH3), 4.53 (2H, s, CH2), 4.93 (2H, s, CH2), 6.43 (1H, s, CH), 7.03 (2H, m, aromatics), 7.41 (2H, m, aromatics). HRMS (ES+) calculated for C18H22FN2O6[M+H]+: 381.146190. Found: 381.146382.
