Rapid and efficient microwave-assisted Friedländer quinoline synthesis

A microwave‐based methodology facilitates reaction of 2‐aminophenylketones with cyclic ketones to form a quinoline scaffold. Syntheses of amido‐ and amino‐linked 17β‐hydroxysteroid dehydrogenase type 3 inhibitors with a benzophenone‐linked motif were pursued using 2‐aminobenzophenone as building blo...

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Main Authors: Bailey, HV, Mahon, M, Vicker, N, Potter, B
Format: Journal article
Language:English
Published: Wiley Open Access 2020
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author Bailey, HV
Mahon, M
Vicker, N
Potter, B
author_facet Bailey, HV
Mahon, M
Vicker, N
Potter, B
author_sort Bailey, HV
collection OXFORD
description A microwave‐based methodology facilitates reaction of 2‐aminophenylketones with cyclic ketones to form a quinoline scaffold. Syntheses of amido‐ and amino‐linked 17β‐hydroxysteroid dehydrogenase type 3 inhibitors with a benzophenone‐linked motif were pursued using 2‐aminobenzophenone as building block. Two amido‐linked targets were achieved in modest yield, but when using microwave‐assisted reductive amination for the amino‐linked counterparts an unexpected product was observed. X‐ray crystallography revealed it as a quinoline derivative, leading to optimisation of a simple and efficient modification of Friedländer methodology. Using reagents and acetic acid catalyst in organic solvent the unassisted reaction proceeds only over several days and in very poor yield. However, by employing neat acetic acid as both solvent and acid catalyst with microwave irradiation at 160 °C quinoline synthesis is achieved in 5 minutes in excellent yield. This has advantages over the previously reported high temperatures or strong acids required, not least given the green credentials of acetic acid, and examples using diverse ketones illustrate applicability. Additionally, he unassisted reaction proceeds effectively at room temperature, albeit much more slowly.
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spelling oxford-uuid:ee86407d-f9bc-4227-9c3f-5b4e14591ce32022-03-27T11:33:22ZRapid and efficient microwave-assisted Friedländer quinoline synthesisJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ee86407d-f9bc-4227-9c3f-5b4e14591ce3EnglishSymplectic ElementsWiley Open Access2020Bailey, HVMahon, MVicker, NPotter, BA microwave‐based methodology facilitates reaction of 2‐aminophenylketones with cyclic ketones to form a quinoline scaffold. Syntheses of amido‐ and amino‐linked 17β‐hydroxysteroid dehydrogenase type 3 inhibitors with a benzophenone‐linked motif were pursued using 2‐aminobenzophenone as building block. Two amido‐linked targets were achieved in modest yield, but when using microwave‐assisted reductive amination for the amino‐linked counterparts an unexpected product was observed. X‐ray crystallography revealed it as a quinoline derivative, leading to optimisation of a simple and efficient modification of Friedländer methodology. Using reagents and acetic acid catalyst in organic solvent the unassisted reaction proceeds only over several days and in very poor yield. However, by employing neat acetic acid as both solvent and acid catalyst with microwave irradiation at 160 °C quinoline synthesis is achieved in 5 minutes in excellent yield. This has advantages over the previously reported high temperatures or strong acids required, not least given the green credentials of acetic acid, and examples using diverse ketones illustrate applicability. Additionally, he unassisted reaction proceeds effectively at room temperature, albeit much more slowly.
spellingShingle Bailey, HV
Mahon, M
Vicker, N
Potter, B
Rapid and efficient microwave-assisted Friedländer quinoline synthesis
title Rapid and efficient microwave-assisted Friedländer quinoline synthesis
title_full Rapid and efficient microwave-assisted Friedländer quinoline synthesis
title_fullStr Rapid and efficient microwave-assisted Friedländer quinoline synthesis
title_full_unstemmed Rapid and efficient microwave-assisted Friedländer quinoline synthesis
title_short Rapid and efficient microwave-assisted Friedländer quinoline synthesis
title_sort rapid and efficient microwave assisted friedlander quinoline synthesis
work_keys_str_mv AT baileyhv rapidandefficientmicrowaveassistedfriedlanderquinolinesynthesis
AT mahonm rapidandefficientmicrowaveassistedfriedlanderquinolinesynthesis
AT vickern rapidandefficientmicrowaveassistedfriedlanderquinolinesynthesis
AT potterb rapidandefficientmicrowaveassistedfriedlanderquinolinesynthesis