107-68-6Relevant articles and documents
The hydrolytic reactivity of β-sultams
Baxter, Nicholas J.,Laws, Andrew P.,Rigoreau, Laurent,Page, Michael I.
, p. 2245 - 2246 (1996)
N-Methyl β-sultam undergoes acid- and base-catalysed hydrolysis in water at 30 °C and I = 1.0 mol dm-3 with kH+ = 2.79dm3 mol-1s-1 and KOH = 1.38 × 10-2 dm3 mol-1 s-1. These second-order rate constants are approximately 109 and 107, respectively, greater than those for a similar acyclic sulfonamide. The entropy of activation for the acid-catalysed hydrolysis of the β-sultam is -80 J K-1 mol-1 which may be indicative of unimolecular ring opening, whereas that for the base-catalysed reaction, - 184 J K-1 mol-1, is consistent with a bimolecular process.
Reactivity and mechanism in the hydrolysis of β-sultams
Baxter, Nicholas J.,Rigoreau, Laurent J. M.,Laws, Andrew P.,Page, Michael I.
, p. 3375 - 3385 (2007/10/03)
β-Sultams show extraordinary rate enhancements of 109-and 107-fold, respectively, compared with the acid-and base-catalyzed hydrolysis of corresponding acyclic sulfonamides. They are about 103-fold more reactive than analogous β-lactams. The alkaline hydrolysis of some β-sultams shows a rate term that is second-order in hydroxide ion concentration, which is indicative of a stepwise mechanism involving a trigonal bipyramidal intermediate (TBPI). The Bronsted βlg value for the alkaline hydrolysis of N-aryl-β-sultams is -0.58 and the kinetic solvent isotope effect kH2OOH/kD2OOD is 0.60, compatible with rate-limiting formation of the TBPI. Conversely, kH2OOH/kD2OOD for N-alkyl-β-sultams is 1.55, indicative of rate-limiting breakdown of the TBPI. The acid-catalyzed hydrolysis of β-sultams is strongly retarded by electron-withdrawing groups α to the sulfonyl group, and it is suggested that the mechanism may involve unimolecular ring opening to generate a sulfonylium ion. The Bronsted βlg value for the acid-catalyzed hydrolysis of N-benzyl-β-sultams is 0.32. The general-acid-catalyzed hydrolysis of N-benzyl-β-sultam by carboxylic acids shows a Bronsted α value of 0.67 and is attributed to a specific acid-nucleophilic mechanism with the formation of a mixed-anhydride intermediate.
Phthalocyanine reactive dyestuffs
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, (2008/06/13)
Phthalocyanine reactive dyestuffs which, in the form of the free acid, have the formula (1) STR1 in which the variable radicals have the meaning given in the description, are prepared by condensation of the corresponding amines with cyanuric fluoride or cyanuric chloride in any desired order. The reactive dyestuffs according to the invention exhibit good wet and light fastness properties and are used for the dyeing and printing of cotton.