Ethyl chloroformate was treated with potassium thiocyanate in ethyl acetate in the presence of a catalysis N,N,N',N'-tetramethylethylenediamine to produce the ethoxycarbonylisothiocyanate. This compound can directly react with 3-amino-pyridine without isolation to afford N-ethoxycarbonyl-N'-(3-pyridyl)- thiourea. The compound crystallized in the monoclinic system with space group P2(1)/c and a＝1.0333(6) nm, b＝0.7118(4) nm, c＝1.5160(8) nm, α＝γ＝90.00°, β＝98.517(8)°, V＝1.1028(10) nm³, Z＝4. The thiourea molecule formed a supermolecule by hydrogen banding.

Key words: crystal structure, synthesis, 3-aminopyridine