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.
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.
Zhao
Jun-Feng
JF
Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China.
Xie
Chang
C
Xu
Sheng-Zhen
SZ
Ding
Ming-Wu
MW
Xiao
Wen-Jing
WJ
D018360:Crystallography, X-Ray; D007097:Imines / Q000737:chemistry; D015394:Molecular Structure; D010753:Phosphoranes / Q000737:chemistry*; D011744:Pyrimidinones / Q000138:chemical synthesis*
D007097:Imines; D010753:Phosphoranes; D011744:Pyrimidinones