1,2,3-Benzoxathiazole 2,2-dioxides: synthesis, mechanism of hydrolysis, and reactions with nucleophiles
摘要:
The rates of base-induced hydrolysis of some five-membered cyclic sulfamates, X-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxides (1a, X = H; 1b, X = 5-Me; 1c, X = 5-t-Bu; 1d, X = 5-Br; 1e, X = 5-Cl; 1f, X = 5-Ac; 1g, X = 5-NO2; 8a, X = 6-NO2) were measured in aqueous acetonitrile. The hydrolyses occurred with cleavage of the endocyclic N-SO2 bond. A Hammett plot using sigma-m values for 1a-g and sigma-p for 8a had rho = +2.20. Activation enthalpies and entropies were measured for 1a and for 3-methyl-1,2,3-benzoxathiazole 2,2-dioxide (10). Volumes of activation were determined for 1g and for 8a. The mechanistic profile for hydrolysis resembled that for the saponification of the analogous sultones and cyclic sulfates. These first examples of 1,2,3-benzoxathiazole 2,2-dioxides (1a-g, 8a) were prepared by treating N-(2-hydroxyphenyl)-p-toluenesulfonamides with sulfuryl chloride and triethylamine or by oxidizing the monoxide precursors using m-chloroperbenzoic acid. Treatment of 1a with potassium fluoride gave 1,2,3-benzoxathiazole 2,2-dioxide (9), which was methylated to give 10. Sulfamate 1a was treated with various nucleophilic reagents: phenyllithium, methyllithium, potassium fluoride, methylamine, tert-butylamine, and sodium methoxide. The first three attacked the tosyl sulfur atom and cleaved the exocyclic N-SO2 bond. The amines attacked the endocyclic sulfonyl sulfur atom and cleaved the endocyclic N-SO2 bond. Sodium methoxide attacked both sulfonyl groups.
1,2,3-Benzoxathiazole 2,2-dioxides: synthesis, mechanism of hydrolysis, and reactions with nucleophiles
摘要:
The rates of base-induced hydrolysis of some five-membered cyclic sulfamates, X-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxides (1a, X = H; 1b, X = 5-Me; 1c, X = 5-t-Bu; 1d, X = 5-Br; 1e, X = 5-Cl; 1f, X = 5-Ac; 1g, X = 5-NO2; 8a, X = 6-NO2) were measured in aqueous acetonitrile. The hydrolyses occurred with cleavage of the endocyclic N-SO2 bond. A Hammett plot using sigma-m values for 1a-g and sigma-p for 8a had rho = +2.20. Activation enthalpies and entropies were measured for 1a and for 3-methyl-1,2,3-benzoxathiazole 2,2-dioxide (10). Volumes of activation were determined for 1g and for 8a. The mechanistic profile for hydrolysis resembled that for the saponification of the analogous sultones and cyclic sulfates. These first examples of 1,2,3-benzoxathiazole 2,2-dioxides (1a-g, 8a) were prepared by treating N-(2-hydroxyphenyl)-p-toluenesulfonamides with sulfuryl chloride and triethylamine or by oxidizing the monoxide precursors using m-chloroperbenzoic acid. Treatment of 1a with potassium fluoride gave 1,2,3-benzoxathiazole 2,2-dioxide (9), which was methylated to give 10. Sulfamate 1a was treated with various nucleophilic reagents: phenyllithium, methyllithium, potassium fluoride, methylamine, tert-butylamine, and sodium methoxide. The first three attacked the tosyl sulfur atom and cleaved the exocyclic N-SO2 bond. The amines attacked the endocyclic sulfonyl sulfur atom and cleaved the endocyclic N-SO2 bond. Sodium methoxide attacked both sulfonyl groups.
Acid-Catalysed Hydrolysis of Some Aromatic Cyclic Sulfamates
作者:Yunus Bekdemir、Halil Kutuk、Sibel Celik、John G. Tillett
DOI:10.1080/10426500210670
日期:2002.4.1
The acid catalysed hydrolysis of some cyclic sulfamates, X-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxides ( 1a , X = Me; 1b , X = H; 1c , X = Cl; 1d , X = NO 2 ) have been studied in concentrated aqueous sulfuric and perchloric acid solutions. Analysis of the data by the Excess Acidity Method, activation parameters, substituent, solvent deuterium isotope effect and order of the catalytic effects
一些环状氨基磺酸盐的酸催化水解,X-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxides (1a, X = Me; 1b, X = H; 1c, X = Cl; 1d , X = NO 2 ) 在浓硫酸和高氯酸水溶液中进行了研究。过量酸度法的数据分析、活化参数、取代基、溶剂氘同位素效应和酸的催化效应顺序都与研究范围内的A-1机理一致。
Acidity of Cyclic Sulfamates: Study of Substituted 1,2,3-Benzoxathiazole 2,2-Dioxides and Theoretical Investigation of the Effect of Conformation on Acidity
作者:Kenneth K. Andersen、Martin G. Kociolek
DOI:10.1021/jo00112a022
日期:1995.4
Sulfamate 1b, 5-nitro-3-(4-toluenesulfonyl)-1,2,3-benzoxathiazole 2,2- dioxide, was treated with various nucleophiles: imidazole, benzylamine, tert-butylamine, sodium azide, potassium fluoride, pyridine, and sodium hydroxide. The first five attacked the exocyclic (tosyl) sulfur atom. No reaction was observed with the pyridine. The hydroxide ion attacked the endocyclic sulfur atom leading to opening of the benzoxathiazole ring. Several N-unsubstituted cyclic sulfamates, X-3H-1,2,3-benzoxathiazole 2,2-dioxides (2a, X = 5-H; 2b, X = 5-NO2; 2c, X = 5-Me; 2d, X = 5-Br; 2e, X = 5-Cl; 2f, X = 6-NO2; 2g, X = 5,6-Cl,Cl) and the naphtho-fused cyclic sulfamate (2h), were prepared by treatment of the respective N-tosyl compounds (1a-h) with sodium azide or potassium fluoride. The pK(a) values for these compounds were determined by potentiometric titration in 60% v/v EtOH/H2O. A Hammett plot using sigma(m) for 2a-e, sigma(p) for 2f, and both sigma(m) and sigma(p) for 2g gave a rho = 2.74. Ab initio calculations were done using sulfamic acid as a simple sulfamate model to test the effect of the geometry changes on pK(a). The calculations showed that the sulfamate with the ringlike geometry should be 3.6 pK(a) units more acidic than the acyclic sulfamate. This overall change was broken down into three factors affecting the pK(a). The N-S bond rotation accounted for a change of 0.22 units, O-S bond rotation for 2.03 units, and ring strain for 1.36 units.