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

doi:10.1016/j.tetlet.2004.03.142

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^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

11 Citations (Scopus)

Abstract

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 language	English
Pages (from-to)	4105-4108
Number of pages	4
Journal	Tetrahedron Letters
Volume	45
Issue number	21
DOIs	https://doi.org/10.1016/j.tetlet.2004.03.142
Publication status	Published - 2004 May 17
Externally published	Yes

Keywords

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

ASJC Scopus subject areas

Biochemistry
Drug Discovery
Organic Chemistry

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10.1016/j.tetlet.2004.03.142

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

abstract = "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.",

keywords = "4,5-Diaminopyrazole, Curtius rearrangement, Pyrazolo[3,4-b]pyrazine",

author = "Chien, {Tun Cheng} and Smaldone, {Ronald A.} and Townsend, {Leroy B.}",

note = "Funding Information: This work was supported by Research Grant 5-PO1-AI46390 from the National Institutes of Health.",

year = "2004",

month = may,

day = "17",

doi = "10.1016/j.tetlet.2004.03.142",

language = "English",

volume = "45",

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journal = "Tetrahedron Letters",

issn = "0040-4039",

publisher = "Elsevier Limited",

number = "21",

}

TY - JOUR

T1 - Facile synthesis of 1-substituted 4,5-diaminopyrazoles and its application toward the synthesis of pyrazolo[3,4-b]pyrazines

AU - Chien, Tun Cheng

AU - Smaldone, Ronald A.

AU - Townsend, Leroy B.

N1 - Funding Information: This work was supported by Research Grant 5-PO1-AI46390 from the National Institutes of Health.

PY - 2004/5/17

Y1 - 2004/5/17

N2 - 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.

AB - 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.

KW - 4,5-Diaminopyrazole

KW - Curtius rearrangement

KW - Pyrazolo[3,4-b]pyrazine

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DO - 10.1016/j.tetlet.2004.03.142

M3 - Article

AN - SCOPUS:2342626685

SN - 0040-4039

VL - 45

SP - 4105

EP - 4108

JO - Tetrahedron Letters

JF - Tetrahedron Letters

IS - 21

ER -

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

Abstract

Keywords

ASJC Scopus subject areas

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