Stereoselective synthesis of novel Δ5- androstenoarylpyrazoline derivatives by BF3·OEt 2-induced intramolecular 1,3-dipolar cycloaddition

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Abstract

The phenylhydrazones of an unsaturated D-seco-pregnene aldehyde underwent BF3·OEt2-induced intramolecular 1,3-dipolar cycloaddition to afford new pyrazoline-fused Δ5-androstene derivatives under extremely mild conditions. The ring closures occurred stereoselectively in good to excellent yields via the corresponding azomethine imine intermediates and showed marked dependence on the electronic feature of the p-phenyl substituent.

Original languageEnglish
Pages (from-to)1311-1313
Number of pages3
JournalSynlett
Issue number8
DOIs
Publication statusPublished - May 16 2007

Fingerprint

Pregnenes
Androstenes
Imines
Cycloaddition
Aldehydes
Derivatives
azomethine
phenylhydrazone

Keywords

  • 1,3-dipolar cycloaddition
  • Hydrazones
  • Lewis acid
  • Stereoselectivity
  • Steroids

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

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title = "Stereoselective synthesis of novel Δ5- androstenoarylpyrazoline derivatives by BF3·OEt 2-induced intramolecular 1,3-dipolar cycloaddition",
abstract = "The phenylhydrazones of an unsaturated D-seco-pregnene aldehyde underwent BF3·OEt2-induced intramolecular 1,3-dipolar cycloaddition to afford new pyrazoline-fused Δ5-androstene derivatives under extremely mild conditions. The ring closures occurred stereoselectively in good to excellent yields via the corresponding azomethine imine intermediates and showed marked dependence on the electronic feature of the p-phenyl substituent.",
keywords = "1,3-dipolar cycloaddition, Hydrazones, Lewis acid, Stereoselectivity, Steroids",
author = "E. Frank and Zsolt Kardos and J. W{\"o}lfling and G. Schneider",
year = "2007",
month = "5",
day = "16",
doi = "10.1055/s-2007-977452",
language = "English",
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T1 - Stereoselective synthesis of novel Δ5- androstenoarylpyrazoline derivatives by BF3·OEt 2-induced intramolecular 1,3-dipolar cycloaddition

AU - Frank, E.

AU - Kardos, Zsolt

AU - Wölfling, J.

AU - Schneider, G.

PY - 2007/5/16

Y1 - 2007/5/16

N2 - The phenylhydrazones of an unsaturated D-seco-pregnene aldehyde underwent BF3·OEt2-induced intramolecular 1,3-dipolar cycloaddition to afford new pyrazoline-fused Δ5-androstene derivatives under extremely mild conditions. The ring closures occurred stereoselectively in good to excellent yields via the corresponding azomethine imine intermediates and showed marked dependence on the electronic feature of the p-phenyl substituent.

AB - The phenylhydrazones of an unsaturated D-seco-pregnene aldehyde underwent BF3·OEt2-induced intramolecular 1,3-dipolar cycloaddition to afford new pyrazoline-fused Δ5-androstene derivatives under extremely mild conditions. The ring closures occurred stereoselectively in good to excellent yields via the corresponding azomethine imine intermediates and showed marked dependence on the electronic feature of the p-phenyl substituent.

KW - 1,3-dipolar cycloaddition

KW - Hydrazones

KW - Lewis acid

KW - Stereoselectivity

KW - Steroids

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