S(Cl)(Cl)(=O)=O.[N:6]1[CH:11]=[CH:10][CH:9]=[C:8]([C:12](=[O:21])[CH2:13][C:14](=O)[C:15]([O:17][CH2:18][CH3:19])=[O:16])[CH:7]=1.[NH2:22][C:23]([NH2:25])=[S:24].C(=O)([O-])[O-].[K+].[K+]>C(Cl)Cl.O1CCCC1.O>[NH2:25][C:23]1[S:24][C:13]([C:12](=[O:21])[C:8]2[CH:9]=[CH:10][CH:11]=[N:6][CH:7]=2)=[C:14]([C:15]([O:17][CH2:18][CH3:19])=[O:16])[N:22]=1
A solution of sulfuryl chloride (2.84 g) in methylene chloride (5 ml) was dropwise added to a solution of ethyl 4-(3-pyridyl)-2,4-dioxo-butyrate (4.42 g) in methylene chloride (40 ml) at 18° C. to 30° C. After being stirred at ambient temperature for one hour, the mixture was added to a solution of thiourea (4.56 g) in a mixture of tetrahydrofuran (50 ml) and water (10 ml). The resulting mixture was adjusted to pH 7.5 with 20% aqueous potassium carbonate and stirred for one hour, and then the solvent was removed in vacuo. To the residue was added a mixture of water and ethyl acetate, and the mixture is acidified to pH 1.0 with 10% hydrochloric acid. The separated aqueous layer was adjusted to pH 9.0 with 20% aqueous potassium carbonate and extracted with ethyl acetate. The extract was dried over magnesium sulfate and evaporated in vacuo. The residue was recrystallized from a mixture of ethyl acetate and tetrahydrofuran to give ethyl 2-amino-5-nicotinoyl-4-thiazolecarboxylate (0.9 g). mp 221° C. (dec.)
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