Methanol → [(4-Chlorophenyl)hydrazono]acetic acid methyl ester

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반응 단계

A suspension of 4-chloro-phenylhydrazine hydrochloride (29, 16.0 g, 89.4 mmol) in anhydrous MeOH (100 mL) was treated dropwise with a solution of ethylglycolate (50% solution in toluene, 20.06 g, 98.3 mmol, 1.1 equiv) in toluene at 25° C. under N2. The resulting reaction mixture was then warmed to reflux for 12 h. When TLC and HPLC showed the reaction was deemed complete, the solvent was removed in vacuo. The residue was then treated with 50% of CH2Cl2 and hexane (v/v, 100 mL) at 25° C. for 30 min with good stirring. The pale-yellow solids were collected by filtration, washed with 50% of CH2Cl2 and hexane (v/v, 2×50 mL), and dried at 40–45° C. in vacuo for 12 h to afford the crude, desired [(4-chlorophenyl)hydrazono]acetic acid methyl ester (30, 15.6 g, 19.0 g theoretical, 82%), which was found to be pure enough to do the following reaction without further purification. For 30: CIMS m/z 211/213 (M+—H, C9H9ClN2O2).

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