New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid

Background: For the synthesis of tri and tetra-substituted alkenes, Knoevenagel condensations have previously been performed in solvents like dichloromethane, DMF, toluene, acetonitrile, DMSO etc. These conditions suffer from certain limitations like long reaction times are required in DMSO or harsh...

Full description

Bibliographic Details
Published in:Letters in Organic Chemistry
Main Author: Muhammad M.T.; Khan K.M.; Taha M.; Khan T.; Hussain S.; Fakhri M.I.; Perveen S.; Voelter W.
Format: Article
Language:English
Published: Bentham Science Publishers B.V. 2016
Online Access:https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958972646&doi=10.2174%2f1570178613666160109005421&partnerID=40&md5=648cf4f09b4b325b1c2e0d6610e3b455
id 2-s2.0-84958972646
spelling 2-s2.0-84958972646
Muhammad M.T.; Khan K.M.; Taha M.; Khan T.; Hussain S.; Fakhri M.I.; Perveen S.; Voelter W.
New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
2016
Letters in Organic Chemistry
13
3
10.2174/1570178613666160109005421
https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958972646&doi=10.2174%2f1570178613666160109005421&partnerID=40&md5=648cf4f09b4b325b1c2e0d6610e3b455
Background: For the synthesis of tri and tetra-substituted alkenes, Knoevenagel condensations have previously been performed in solvents like dichloromethane, DMF, toluene, acetonitrile, DMSO etc. These conditions suffer from certain limitations like long reaction times are required in DMSO or harsh heating conditions are necessary using DMF as a solvent decreasing the yields to below 50%. Tedious work up is required after long reaction times or/and high temperatures, if the reaction is performed in toluene. Methods: In a typical reaction, 1 mmol of aromatic aldehyde with 1.1 mmol of malanonitrile in the presence of bismuth nitrate (3 mmol%) was refluxed in water (10 ml) for 25-30 min. After completion of the reaction (TLC analysis), excess bismuth nitrate was filtered for next use and the filtrate was kept at room temperature over night for crystallization. Crystals were filtered, washed with water and dried. In a separate reaction the catalyst was re-used for the one of the same reactions and found satisfactory results. Results: In order to generalize our newly developed methodology, we selected a variety of aldehydes to synthesize different trisubstituted alkenes and found that this method can also be applied on aromatic aldehydes. For comparison purposes, the reaction was carried out in ethanol in parallel to water and found that water is the best solvent for this reaction. Conclusion: In summary, we have discovered a facile and rapid method for Knoevenagel condensations using bismuth nitrate as Lewis acid. The advantages of bismuth nitrate as a catalyst are: easy to remove from the reaction mixture by simple filtration, recyclable, requires water as solvent, is eco-friendly and afforded high yields (90-97%). © 2016 Bentham Science Publishers.
Bentham Science Publishers B.V.
15701786
English
Article

author Muhammad M.T.; Khan K.M.; Taha M.; Khan T.; Hussain S.; Fakhri M.I.; Perveen S.; Voelter W.
spellingShingle Muhammad M.T.; Khan K.M.; Taha M.; Khan T.; Hussain S.; Fakhri M.I.; Perveen S.; Voelter W.
New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
author_facet Muhammad M.T.; Khan K.M.; Taha M.; Khan T.; Hussain S.; Fakhri M.I.; Perveen S.; Voelter W.
author_sort Muhammad M.T.; Khan K.M.; Taha M.; Khan T.; Hussain S.; Fakhri M.I.; Perveen S.; Voelter W.
title New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
title_short New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
title_full New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
title_fullStr New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
title_full_unstemmed New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
title_sort New facile, eco-friendly and rapid synthesis of trisubstituted alkenes using bismuth nitrate as lewis acid
publishDate 2016
container_title Letters in Organic Chemistry
container_volume 13
container_issue 3
doi_str_mv 10.2174/1570178613666160109005421
url https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958972646&doi=10.2174%2f1570178613666160109005421&partnerID=40&md5=648cf4f09b4b325b1c2e0d6610e3b455
description Background: For the synthesis of tri and tetra-substituted alkenes, Knoevenagel condensations have previously been performed in solvents like dichloromethane, DMF, toluene, acetonitrile, DMSO etc. These conditions suffer from certain limitations like long reaction times are required in DMSO or harsh heating conditions are necessary using DMF as a solvent decreasing the yields to below 50%. Tedious work up is required after long reaction times or/and high temperatures, if the reaction is performed in toluene. Methods: In a typical reaction, 1 mmol of aromatic aldehyde with 1.1 mmol of malanonitrile in the presence of bismuth nitrate (3 mmol%) was refluxed in water (10 ml) for 25-30 min. After completion of the reaction (TLC analysis), excess bismuth nitrate was filtered for next use and the filtrate was kept at room temperature over night for crystallization. Crystals were filtered, washed with water and dried. In a separate reaction the catalyst was re-used for the one of the same reactions and found satisfactory results. Results: In order to generalize our newly developed methodology, we selected a variety of aldehydes to synthesize different trisubstituted alkenes and found that this method can also be applied on aromatic aldehydes. For comparison purposes, the reaction was carried out in ethanol in parallel to water and found that water is the best solvent for this reaction. Conclusion: In summary, we have discovered a facile and rapid method for Knoevenagel condensations using bismuth nitrate as Lewis acid. The advantages of bismuth nitrate as a catalyst are: easy to remove from the reaction mixture by simple filtration, recyclable, requires water as solvent, is eco-friendly and afforded high yields (90-97%). © 2016 Bentham Science Publishers.
publisher Bentham Science Publishers B.V.
issn 15701786
language English
format Article
accesstype
record_format scopus
collection Scopus
_version_ 1809677910089400320