Document Detail

Carboxyketenes from 4-hydroxy-1,3-oxazin-6-ones and Meldrum's acid derivatives.
MedLine Citation:
PMID:  17253756     Owner:  NLM     Status:  PubMed-not-MEDLINE    
New 4-hydroxy-1,3-oxazin-6-ones 8 and 16 were prepared from chlorocarbonyl(phenyl)ketene and amides. The flash vacuum thermolysis (FVT) reactions of these compounds and the 4-methoxy derivative 17 were investigated by Ar matrix isolation IR spectroscopy and online mass spectrometry including MS/MS analysis. Carboxy(phenyl)ketene 10 is formed as the major product by thermal fragmentation of 4-hydroxy-1,3-oxazin-6-one 8. This takes place via the unstable 6-hydroxy tautomer 9. Another tautomer, the 5H-isomer 12, leads to the formation of benzoyl isocyanate 13 as a minor product together with phenylketene 14. Carboxy(phenyl)ketene 10 remains detectable at high FVT temperatures but undergoes thermal decarboxylation to phenylketene 14. The same carboxy(phenyl)ketene 10 is also produced in significant amounts by FVT of 5-phenyl-Meldrum's acid 18 via the unstable enol tautomer 19. A small amount of the unsubstituted carboxyketene 20 is observable on FVT of Meldrum's acid 1 itself.
Lisa George; Rakesh Naduvile Veedu; Hassan Sheibani; Avat Arman Taherpour; Robert Flammang; Curt Wentrup
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-01-25
Journal Detail:
Title:  The Journal of organic chemistry     Volume:  72     ISSN:  0022-3263     ISO Abbreviation:  J. Org. Chem.     Publication Date:  2007 Feb 
Date Detail:
Created Date:  2007-02-09     Completed Date:  2007-04-17     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985193R     Medline TA:  J Org Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1399-404     Citation Subset:  -    
Chemistry Building, School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
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