Source:http://linkedlifedata.com/resource/pubmed/id/16186929
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
16
|
| pubmed:dateCreated |
2005-9-27
|
| pubmed:abstractText |
6A-Amino-6A-deoxy-beta-cyclodextrin enhances the rate of the deprotonation of 4-tert-butyl-alpha-nitrotoluene. The rate constants for reaction of the cyclodextrin-bound species, kinc = 4 x 10(-3), 9 x 10(-3) and 19 x 10(-3) s(-1), at pH 6.0, 6.5 and 7.0, respectively, in 0.1 mol dm(-3) aqueous phosphate buffer containing 1% methanol at 298 K. These rate constants correspond to a rate acceleration (kinc/kun) of ca. 10 times at each pH. Under the same conditions, 6A-dimethylamino-6A-deoxy-beta-cyclodextrin and 6A-(2-aminoethylamino)-6A-deoxy-beta-cyclodextrin are more effective; at pH 6.0, 6.5 and 7.0, for the former, kinc = 3 x 10(-2), 7 x 10(-2) and 12 x 10(-2) s(-1), whilst for the latter, kinc = 4 x 10(-2), 5 x 10(-2) and 9 x 10(-2) s(-1), respectively. Each cyclodextrin also decreases the pKa of the nitrotoluene, from 6.8 in free solution, to 6.2 when bound. The accelerated deprotonation by 6A-amino-6A-deoxy-beta-cyclodextrin is reflected in the enhanced rates of hydrogen-deuterium exchange of the nitrotoluene in deuterium oxide, and in the conjugate addition of the nitrotoluene to methyl vinyl ketone in aqueous solution.
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Aug
|
| pubmed:issn |
1477-0520
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
21
|
| pubmed:volume |
3
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
2990-3
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
2005
|
| pubmed:articleTitle |
Aminocyclodextrins to facilitate the deprotonation of 4-tert-butyl-alpha-nitrotoluene.
|
| pubmed:affiliation |
Research School of Chemistry, Institute of Advanced Studies, Australian National University, Canberra, ACT 0200, Australia.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|