Alternate synthesis route of 2-(substituted phenyl)-3,3a-dihydro-8H- pyrazolo[5,1-a[isoindol-8-ones via chalcone-based n-formyl-pyrazolines

Naseem Ahmed; Dharm Dev

doi:10.1080/00397911.2011.606414

Alternate synthesis route of 2-(substituted phenyl)-3,3a-dihydro-8H- pyrazolo[5,1-a[isoindol-8-ones via chalcone-based n-formyl-pyrazolines

Naseem Ahmed, Dharm Dev

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

6 Scopus citations

Abstract

An alternate approach to 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5, l-a] isoindol-8-ones via chalcone-based N-formyl-pyrazolines is described. N-Formyl-pyrazolines were prepared in excellent yield (81-96%) by the reaction of chalcones with hydrazine hydrate in the presence of formic acid, which undergoes intramolecular Friedel-Crafts acylation in the presence of trifluoroacetic acid (TFA) as a catalyst to afford functionalized 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,1-a]isoindol-8-ones in good to excellent yield (74-94%) at reflux in acetonitrile. Our synthetic route avoids expensive reagents and significantly improves yields.

Original language	English
Pages (from-to)	689-704
Number of pages	16
Journal	Synthetic Communications
Volume	43
Issue number	5
DOIs	https://doi.org/10.1080/00397911.2011.606414
State	Published - 1 Jan 2013
Externally published	Yes

Keywords

2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,l-a[isoindol-8-ones
Chalcone N-formyl-2-pyrazoline
Friedel-Crafts acylation

ASJC Scopus subject areas

Organic Chemistry

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10.1080/00397911.2011.606414

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title = "Alternate synthesis route of 2-(substituted phenyl)-3,3a-dihydro-8H- pyrazolo[5,1-a[isoindol-8-ones via chalcone-based n-formyl-pyrazolines",

abstract = "An alternate approach to 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5, l-a] isoindol-8-ones via chalcone-based N-formyl-pyrazolines is described. N-Formyl-pyrazolines were prepared in excellent yield (81-96%) by the reaction of chalcones with hydrazine hydrate in the presence of formic acid, which undergoes intramolecular Friedel-Crafts acylation in the presence of trifluoroacetic acid (TFA) as a catalyst to afford functionalized 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,1-a]isoindol-8-ones in good to excellent yield (74-94%) at reflux in acetonitrile. Our synthetic route avoids expensive reagents and significantly improves yields.",

keywords = "2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,l-a[isoindol-8-ones, Chalcone N-formyl-2-pyrazoline, Friedel-Crafts acylation",

author = "Naseem Ahmed and Dharm Dev",

note = "Funding Information: This work was financially supported by the Indian Institute of Technology Roorkee through Ministry of Human Resource Development (MHRD), New Delhi. D. D. thanks MHRD for the award of fellowship.",

year = "2013",

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doi = "10.1080/00397911.2011.606414",

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journal = "Synthetic Communications",

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AU - Ahmed, Naseem

AU - Dev, Dharm

N1 - Funding Information: This work was financially supported by the Indian Institute of Technology Roorkee through Ministry of Human Resource Development (MHRD), New Delhi. D. D. thanks MHRD for the award of fellowship.

PY - 2013/1/1

Y1 - 2013/1/1

N2 - An alternate approach to 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5, l-a] isoindol-8-ones via chalcone-based N-formyl-pyrazolines is described. N-Formyl-pyrazolines were prepared in excellent yield (81-96%) by the reaction of chalcones with hydrazine hydrate in the presence of formic acid, which undergoes intramolecular Friedel-Crafts acylation in the presence of trifluoroacetic acid (TFA) as a catalyst to afford functionalized 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,1-a]isoindol-8-ones in good to excellent yield (74-94%) at reflux in acetonitrile. Our synthetic route avoids expensive reagents and significantly improves yields.

AB - An alternate approach to 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5, l-a] isoindol-8-ones via chalcone-based N-formyl-pyrazolines is described. N-Formyl-pyrazolines were prepared in excellent yield (81-96%) by the reaction of chalcones with hydrazine hydrate in the presence of formic acid, which undergoes intramolecular Friedel-Crafts acylation in the presence of trifluoroacetic acid (TFA) as a catalyst to afford functionalized 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,1-a]isoindol-8-ones in good to excellent yield (74-94%) at reflux in acetonitrile. Our synthetic route avoids expensive reagents and significantly improves yields.

KW - 2-(substituted phenyl)-3,3a-dihydro-8H-pyrazolo[5,l-a[isoindol-8-ones

KW - Chalcone N-formyl-2-pyrazoline

KW - Friedel-Crafts acylation

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DO - 10.1080/00397911.2011.606414

M3 - Article

AN - SCOPUS:84869425178

SN - 0039-7911

VL - 43

SP - 689

EP - 704

JO - Synthetic Communications

JF - Synthetic Communications

IS - 5

ER -

Alternate synthesis route of 2-(substituted phenyl)-3,3a-dihydro-8H- pyrazolo[5,1-a[isoindol-8-ones via chalcone-based n-formyl-pyrazolines

Abstract

Keywords

ASJC Scopus subject areas

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