Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles

David M. Dastrup, Amy H. Yap, Steven M. Weinreb, James R. Henry, Andrew J. Lechleiter

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

β-Tosylethylhydrazine (6) can be prepared efficiently in one step from commercially available p-tolyl vinyl sulfone (7) and hydrazine hydrate. This hydrazine reacts with both 1,3-diketones and conjugated ynones in glacial acetic acid to provide a variety of N-tosylethyl-protected (TSE) pyrazoles in good yields. The TSE group can be removed from the pyrazoles using potassium t-butoxide in THF at -30°C-rt. In addition, hydrazine 6 condenses with β-ketonitriles and β-aminoacrylonitriles to afford 5-aminopyrazoles, which can be deprotected by brief treatment with NaOEt in EtOH/DMSO at 45°C.

Original languageEnglish (US)
Pages (from-to)901-906
Number of pages6
JournalTetrahedron
Volume60
Issue number4
DOIs
StatePublished - Jan 19 2004

Fingerprint

hydrazine
Pyrazoles
Dimethyl Sulfoxide
Acetic Acid
Potassium
5-aminopyrazole

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

Cite this

Dastrup, David M. ; Yap, Amy H. ; Weinreb, Steven M. ; Henry, James R. ; Lechleiter, Andrew J. / Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles. In: Tetrahedron. 2004 ; Vol. 60, No. 4. pp. 901-906.
@article{a0a823c0be874bb984f66df7482d1c6c,
title = "Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles",
abstract = "β-Tosylethylhydrazine (6) can be prepared efficiently in one step from commercially available p-tolyl vinyl sulfone (7) and hydrazine hydrate. This hydrazine reacts with both 1,3-diketones and conjugated ynones in glacial acetic acid to provide a variety of N-tosylethyl-protected (TSE) pyrazoles in good yields. The TSE group can be removed from the pyrazoles using potassium t-butoxide in THF at -30°C-rt. In addition, hydrazine 6 condenses with β-ketonitriles and β-aminoacrylonitriles to afford 5-aminopyrazoles, which can be deprotected by brief treatment with NaOEt in EtOH/DMSO at 45°C.",
author = "Dastrup, {David M.} and Yap, {Amy H.} and Weinreb, {Steven M.} and Henry, {James R.} and Lechleiter, {Andrew J.}",
year = "2004",
month = "1",
day = "19",
doi = "10.1016/j.tet.2003.11.046",
language = "English (US)",
volume = "60",
pages = "901--906",
journal = "Tetrahedron",
issn = "0040-4020",
publisher = "Elsevier Limited",
number = "4",

}

Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles. / Dastrup, David M.; Yap, Amy H.; Weinreb, Steven M.; Henry, James R.; Lechleiter, Andrew J.

In: Tetrahedron, Vol. 60, No. 4, 19.01.2004, p. 901-906.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles

AU - Dastrup, David M.

AU - Yap, Amy H.

AU - Weinreb, Steven M.

AU - Henry, James R.

AU - Lechleiter, Andrew J.

PY - 2004/1/19

Y1 - 2004/1/19

N2 - β-Tosylethylhydrazine (6) can be prepared efficiently in one step from commercially available p-tolyl vinyl sulfone (7) and hydrazine hydrate. This hydrazine reacts with both 1,3-diketones and conjugated ynones in glacial acetic acid to provide a variety of N-tosylethyl-protected (TSE) pyrazoles in good yields. The TSE group can be removed from the pyrazoles using potassium t-butoxide in THF at -30°C-rt. In addition, hydrazine 6 condenses with β-ketonitriles and β-aminoacrylonitriles to afford 5-aminopyrazoles, which can be deprotected by brief treatment with NaOEt in EtOH/DMSO at 45°C.

AB - β-Tosylethylhydrazine (6) can be prepared efficiently in one step from commercially available p-tolyl vinyl sulfone (7) and hydrazine hydrate. This hydrazine reacts with both 1,3-diketones and conjugated ynones in glacial acetic acid to provide a variety of N-tosylethyl-protected (TSE) pyrazoles in good yields. The TSE group can be removed from the pyrazoles using potassium t-butoxide in THF at -30°C-rt. In addition, hydrazine 6 condenses with β-ketonitriles and β-aminoacrylonitriles to afford 5-aminopyrazoles, which can be deprotected by brief treatment with NaOEt in EtOH/DMSO at 45°C.

UR - http://www.scopus.com/inward/record.url?scp=0347600589&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0347600589&partnerID=8YFLogxK

U2 - 10.1016/j.tet.2003.11.046

DO - 10.1016/j.tet.2003.11.046

M3 - Article

AN - SCOPUS:0347600589

VL - 60

SP - 901

EP - 906

JO - Tetrahedron

JF - Tetrahedron

SN - 0040-4020

IS - 4

ER -