CC(C)([O-])C.[K+].[O:7]1[CH:11]=[CH:10][CH:9]=[C:8]1/[C:12](=[N:16]/[OH:17])/[C:13]([OH:15])=[O:14].Cl[CH2:19][C:20]([NH:22][O:23][CH3:24])=[O:21].[Cl-].[Na+]>CS(C)=O.O>[O:7]1[CH:11]=[CH:10][CH:9]=[C:8]1/[C:12](=[N:16]/[O:17][CH2:19][C:20](=[O:21])[NH:22][O:23][CH3:24])/[C:13]([OH:15])=[O:14]Potassium tert-butoxide (6.73 g) was stirred in dry dimethylsulphoxide (30 ml), then Z-2-(fur-2-yl)-2-hydroxyiminoacetic acid (3.11 g) was added to the suspension, which was cooled in an ice-bath, and the mixture was stirred for 1 hr. Methyl chloroacetohydroxamate (2.35 g) in dimethylsulphoxide (2 ml) was added dropwise. The mixture was stirred for 2 hr at room temperature and the resulting solution was poured into ice and water (125 ml). The pH was adjusted to 1 and the solution was saturated with sodium chloride and extracted with ethyl acetate (50+150+4×200 ml), the pH being kept at 1 by addition of more hydrochloric acid as necessary. The ethyl acetate solution was washed with saturated brine (2×50 ml), then dried (Na2SO4) and evaporated, leaving a pale-brown solid. Washing the solid with dichloromethane left the title-compound, 1.56 g, m.p. 129° (decomp.) λmax (EtOH) 272.5 nm (ε 14,700), νmax (Nujol) 3180 (bonded NH), 1753 (CO2H), 1612 and 1522 cm-1 (bonded CONH), τ(DMSO d6) 2.10, 3.15, 3.30 (α-furyl), ca. 4.45 (NH, CO2H), 5.42 (CH2), 6.35 (OCH3).
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