Cl[CH2:2][C:3](=O)[C:4](=[N:10][O:11][CH2:12][CH2:13][CH3:14])[C:5]([O:7][CH2:8][CH3:9])=[O:6].[NH2:16][C:17]([NH2:19])=[S:18].O.C([O-])(=O)C.[Na+].C(=O)([O-])[O-].[K+].[K+]>O.C(O)C>[NH2:19][C:17]1[S:18][CH:2]=[C:3]([C:4](=[N:10][O:11][CH2:12][CH2:13][CH3:14])[C:5]([O:7][CH2:8][CH3:9])=[O:6])[N:16]=1
Ethyl 4-chloro-3-oxo-2-propoxyiminobutyrate (syn isomer, 15.4 g.), thiourea (4.97 g.) and sodium acetate hydrate (8.89 g.) were dissolved in a mixture of water (40 ml.) and ethanol (50 ml.), and stirred at 40° C. for an hour. The reaction mixture was adjusted to pH 6.5 with a saturated aqueous solution of potassium carbonate under cooling and stirred at the same temperature for half an hour. The precipitating crystals were collected by filtration, washed with water and diisopropyl ether, and then dried to give crystalline ethyl 2-(2-amino-4-thiazolyl)-2-propoxyiminoacetate (syn isomer, 10.55 g.), mp 142°-144° C.
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