Aminocyclodextrins to facilitate the deprotonation of 4-tert-butyl-α-nitrotoluene
| dc.contributor.author | Barr, L. | |
| dc.contributor.author | Easton, C. | |
| dc.contributor.author | Lee, K. | |
| dc.contributor.author | Lincoln, S. | |
| dc.date.issued | 2005 | |
| dc.description.abstract | 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. | |
| dc.description.statementofresponsibility | Lorna Barr, Christopher J. Easton, Kitty Lee and Stephen F. Lincoln | |
| dc.identifier.citation | Organic and Biomolecular Chemistry, 2005; 3(16):2990-2993 | |
| dc.identifier.doi | 10.1039/b506187c | |
| dc.identifier.issn | 1477-0520 | |
| dc.identifier.issn | 1477-0539 | |
| dc.identifier.uri | http://hdl.handle.net/2440/17800 | |
| dc.language.iso | en | |
| dc.publisher | Royal Soc Chemistry | |
| dc.rights | © Royal Society of Chemistry 2005 | |
| dc.source.uri | https://doi.org/10.1039/b506187c | |
| dc.subject | Toluene | |
| dc.subject | Cyclodextrins | |
| dc.subject | Hydrogen-Ion Concentration | |
| dc.title | Aminocyclodextrins to facilitate the deprotonation of 4-tert-butyl-α-nitrotoluene | |
| dc.title.alternative | Aminocyclodextrins to facilitate the deprotonation of 4-tert-butyl-alpha-nitrotoluene | |
| dc.type | Journal article | |
| pubs.publication-status | Published |