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Ultrasound promoted N-alkylation of pyrrole using potassium superoxide as base in crown ether.
MedLine Citation:
PMID:  11237050     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Ultrasound accelerates the N-alkylation of pyrrole by alkylating reagents using potassium superoxide as base in the presence of 18-crown-6. A much lower yield of N-alkylated pyrrole was realized in the absence of ultrasound. N-alkylating reagents employed for pyrrole are methyl iodide, ethyl bromide, benzyl bromide, as well as acrylonitrile allyl cyanide and methyl acrylate. In an extension of this work, we have found that ultrasound was not necessary for the N-alkylation of indole and alkyl amine, such as diphenyl amine and piperidine with alkyl halides using our reagents. In all cases we observed that the 18-crown-6 catalyzed N-alkylation reaction gives higher yields of N-alkylated products than that without crown ether, when potassium superoxide was used as base. These observations are probably due to the potassium-crown complex which can be released when the reaction goes to completion.
E S Yim; M K Park; B H Han
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Ultrasonics sonochemistry     Volume:  4     ISSN:  1350-4177     ISO Abbreviation:  Ultrason Sonochem     Publication Date:  1997 Apr 
Date Detail:
Created Date:  2001-03-09     Completed Date:  2001-04-05     Revised Date:  2003-10-31    
Medline Journal Info:
Nlm Unique ID:  9433356     Medline TA:  Ultrason Sonochem     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  95-8     Citation Subset:  -    
Department of Chemistry, College of Natural Sciences, Chungnam National University, Taejon, South Korea.
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