Zhao JF, Xie C, Xu SZ, Ding MW, Xiao WJ. 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.
Org Biomol Chem 2006;
4:130-4. [PMID:
16358007 DOI:
10.1039/b513715b]
[Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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.
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