Facile synthesis of 2-alkylthio-3-amino-4 H-imidazol-4-ones and 2H-imidazo[2,1-b]-1,3,4-thiadiazin-6(7H)-ones via N-vinylic iminophosphorane

2-Alkylthio-3-amino-4H-imidazol-4- ones 5 were synthesized by S-alkylation of 2-thioxo-3-amino-4-imidazolidinones 4, which were obtained via cyclization of isothiocyanates 2 with hydrazine hydrate. 5l–n reacted with Ph3P, C2Cl6, and NEt3 to give 2H-imidazo[2,1-b]-1,3,4-thiadiazin- 6(7H)-ones 7a–c in good yields. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:76–80, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20069