Hydrolysis of Sulfamoyl Chlorides. II. Hydrogen Participation in the Hydrolysis of Diethyl and Methylethylsulfamoyl Chlorides

Abstract

Diethylsulfamoyl chloride (2) hydrolyzes eight times faster than dimethylsulfamoyl chloride (1). In 2 the secondary deuterium isotope effect was found to be about 2, hence hydrogen participation is important in the hydrolysis of this compound. The temperature coefficient of the enthalpy of activation ( A c t ) is exceptional (-39 cal mol-' deg-') for a reaction presumably following an SNI mechanism. The kinetic solvent isotope effect was normal for such a mechanism. The corresponding value of AC: for the hydrolysis of piperidylsulfamoyl chloride (4) was about the same as found for 2 while the value for the methylethyl isomer (3) was -66 cal deg-' mol-', an intermediate value supporting an explanation based on solvent exclusion. Experiments in mixed solvents support the hypothesis that solvent reorganization is the major factor in determining the value of AC: for 2 but not for 4.Le chlorure de dii.thylsulfamoyle (2) hydrolyse huit fois plus vite que le chlorure de dimCthylsulfamoyle (1). Dans 2, l'effet isotopique secondaire du deuterium est trouve a peu prts egal a 2, par suite la participation de I'hydrogtne est importante dans I'hydrolyse de ce composC. Le coefficient de temptrature de l'enthalpie d'activation (AC:) est exceptionnel (-39 cal mol-' deg-') pour une reaction suivant probablement un mecanisme SN1. L'effet isotopique cinetique du solvant ttait normal pour un tel mtcanisme. La valeur correspondante de AC: pour I'hydrolyse du chlorure de pipi.ridylsulfamoyle (4) a ttC environ la meme que celle trouvte pour 2 tandis que la valeur de I'isomere methyltthyl (3) etait de -66 cal deg-' mol-', valeur intermediaire ktayant une explication fondke sur I'exclusion de solvant. Des exptriences dans des solvants melanges ttayent I'hypothtse que la reorganisation du solvant est le facteur principal dans la determination de la valeur de AC: pour 2 mais non pas pour 4.

Rate and product studies in the solvolyses of N,N-dimethylsulfamoyl and 2-propanesulfonyl chlorides

“…An extension to the hydrolyses of other N,N-disubstituted-sulfamoyl chlorides gave substantially less negative values for DC p ‡ , but these were also considered as proceeding by the S N 1 pathway. 10 The interpretation of DC p ‡ values can be considerably more complicated than originally proposed. 11…”

Kinetics of hydrolysis of 1-benzoyl-1,2,4-triazole in aqueous solution as a function of temperature near the temperature of maximum density, and the isochoric controversy

“…In fact, this pattern is shown by published kinetic data for hydrolysis reactions in aqueous solutions as reported by Robertson and co-workers. These data sets also include kinetic data for solvolysis of a range of compounds in water 22-30 and in D 2 O, 22,23,25,31 the TMD of the latter being 284.35 K. The compounds included methyl trifluoroethanoate, succinic and phthalic anhydride, 22 dimethylsulfamoyl chloride, 23 diethyl and methyl(ethyl)sulfamoyl chloride, 24 methanesulfonyl and benzenesulfonyl chloride, 25 methyl chlorosulfate and ethyl chlorosulfate, 27 2-chloroethyl(methyl) sulfide, 28 methyl methanesulfonate 29 and 4-substituted benzenesulfonyl chlorides. 30 Moelwyn-Hughes et al 26 reported rate constants for the solvolysis of 2-chloro-2 methylpropane in aqueous solution at intervals of 1 K from 273.15 to 298.15 K. Novel features in the kinetic data can neither be discerned from isobaric pairs of temperatures nor from around the TMD.…”

The Hydrolysis of Disubstituted Alkyl Phosphorochloridates and N,N,N′,N′-Tetra-stibstituted Phosphorodiamidic Chlorides in Water and Deuterium Oxide: Heat Capacity of Activation and Kinetic Solvent Isotope Effects

“…establishment of "normal values". Thus the whether this is indicative of some failure of remarkable difference in AC,' for the hydrolysis transition state theory as some suspect (1) or of dimethylsulfamoyl chloride (1) (ACp* = -76 due to a lack of proper identification and estima-cal deg-I mol-l, normal for an S,1 mechanism tion of contributing factors is an open question (5)) and that for diethylsulfamoyl chloride (2) which calls for solution if our knowledge in this ( A q * -'' deg-l mol-l) (6) a area is to advance beyond free energy correla-potential difference in solvent reorganization tions. Among the limited areas where recent even though both would be considered to react progress has been made, we may cite the general by an mechanism.…”

“…While the mechanism for the hydrolysis of 7 and 8 is less well established, the basis for possible disagreement is not very persuasive to us (10, 11). The uncertainty here, as in the case of the sulfonyl chlorides (12) and of the sulfamoyl chlorides (5,6) arises from that uncertainty which frequently attends niechanistic deductions based on small or no rate increases above the normal value for hydrolysis following the addition of a series of nucleophiles somewhat stronger than water (9, 13). Hall argued that since 7 exhibited virtually no rate enhancement on the addition of OH-, F -, and EtO-, it hydrolyzed by an S,1 mechanism.…”