Dimethylformamide → N-Hydroxy-3-[1-(4-methoxyphenyl)-5-(3-pyridyl)-3-pyrazolyl]-N-methylpropanamide Monoformate

To a solution of compound 31 (0.9 g, 2 5 mM) in CH2Cl2 (25 ml) at RT was added DMF (0.2 ml) and oxalyl chloride (1.26 g, 10 mM). After stirring for 0.5 hr, the reaction mixture was evaporated in vacuo, redissolved in CH2Cl2 (25 ml) and added dropwise to a solution of methylhydroxylamine hydrochloride (0.84 g, 10 mM) and Et3N (3.7 ml) in CH2Cl2 (50 ml) at 0° C. The reaction was stirred for 10 min and poured into a 1:1 stirred mixture of Ch2Cl2 :H2O. The CH2Cl2 layer was separated, washed (H2O and then brine), dried (Na2SO4) and evaporated in vacuo to give a semi-solid which was purified by column chromatography on Silica employing Hexane:40EtOAc:1% MeOH:0.1% HCO2H as eluent. The title compound 35 was obtained as a tan foam as the monoformate salt; MS, m/e 352 (M+).