title: Iminophosphorane-mediated efficient synthesis of new tricyclic 3,5-dihydro-1,2,3-triazolo[4,5-d]-1,2,4-triazolo[1,5-a]pyrimidin-9-ones.
abstract: The carbodiimides 2, obtained from aza-Wittig reactions of iminophosphorane 1 with aromatic isocyanates, reacted with hydrazine to give selectively 6-amino-7H-1,2,3-triazolo[4,5-d]pyrimidin-7-ones 5. Compounds 5 were further transformed to iminophosphoranes 6 by reaction with triphenylphosphine, hexachloroethane and triethylamine. A tandem aza-Wittig reaction of iminophosphorane 6 with isocyanate or acyl chloride generated previously unreported 3,5-dihydro-1,2,3-triazolo[4,5-d]-1,2,4-triazolo[1,5-a]pyrimidin-9-ones 10 or 12 in satisfactory yield. X-ray structure analysis of 10 g verified the proposed structure and the reaction selectivity.
authors.affiliation: Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China.
authors.forename: Jun-Feng
authors.initials: JF
authors.lastname: Zhao
authors.forename: Chang
authors.initials: C
authors.lastname: Xie
authors.forename: Sheng-Zhen
authors.initials: SZ
authors.lastname: Xu
authors.forename: Ming-Wu
authors.initials: MW
authors.lastname: Ding
authors.forename: Wen-Jing
authors.initials: WJ
authors.lastname: Xiao
mesh_terms: D018360:Crystallography, X-Ray; D007097:Imines / Q000737:chemistry; D015394:Molecular Structure; D010753:Phosphoranes / Q000737:chemistry*; D011744:Pyrimidinones / Q000138:chemical synthesis*
chemical_list: D007097:Imines; D010753:Phosphoranes; D011744:Pyrimidinones