[CH2:1]([O:3][N:4]=[C:5]([C:11](=O)[CH2:12]Cl)[C:6]([O:8][CH2:9][CH3:10])=[O:7])[CH3:2].[NH2:15][C:16]([NH2:18])=[S:17].C([O-])(=O)C.[Na+].C(=O)(O)[O-].[Na+]>O.CO>[NH2:18][C:16]1[S:17][CH:12]=[C:11]([C:5](=[N:4][O:3][CH2:1][CH3:2])[C:6]([O:8][CH2:9][CH3:10])=[O:7])[N:15]=1A mixture of ethyl 2-ethoxyimino-3-oxo-4-chlorobutyrate (syn isomer 38.7 g.), thiourea (13.2 g.), sodium acetate (14.3 g.), methanol (95 ml.) and water (95 ml.) was stirred at 48° C. for 40 minutes. After the resultant solution was adjusted to pH 6.5 with an aqueous solution of sodium bicarbonate, the appeared precipitates were collected by filtration and washed with diisopropyl ether to give ethyl 2-(2-amino-4-thiazolyl)-2-ethoxyiminoacetate (syn isomer, 14.7 g.), mp 130° to 131° C.
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