Facile synthesis of 1-substituted 4,5-diaminopyrazoles and its application toward the synthesis of pyrazolo[3,4-b]pyrazines

Tun-Cheng Chien, Ronald A. Smaldone, Leroy B. Townsend

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9 Citations (Scopus)


1-Substituted 5-aminopyrazole-4-carbonylazides were prepared from the appropriate 5-aminopyrazole-4-carboxylates. The acyl azides undergo a Curtius rearrangement followed by quenching with alcohols to form the corresponding carbamates. The 1-substituted 5-amino-4-benzyloxycarbonylaminopyrazoles were unblocked by catalytic hydrogenolysis to give the desired 4,5-diaminopyrazoles. These 4,5-diaminopyrazoles were immediately condensed with glyoxal to afford 1-substituted pyrazolo[3,4-b]pyrazines.

Original languageEnglish
Pages (from-to)4105-4108
Number of pages4
JournalTetrahedron Letters
Issue number21
Publication statusPublished - 2004 May 17



  • 4,5-Diaminopyrazole
  • Curtius rearrangement
  • Pyrazolo[3,4-b]pyrazine

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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