Solvolysis ofN,N-dimethylthiocarbamoyl chloride: effect of sulfur-for-oxygen substitution upon kinetics and product partitioning

Abstract

A study of the solvolyses of N,N-dimethylcarbamoyl chloride (1) was extended to the solvolyses of N,N-dimethylthiocarbamoyl chloride (2). The specific rates of solvolysis of 2 at 0.0°C are two to three orders of magnitude greater than those for 1. Analysis of the data using the extended Grunwald-Winstein equation leads to sensitivities l and m and an l/m ratio which are lower for 2 than those previously reported for 1. Product selectivities in mixtures of water with ethanol or methanol indicate a greater preference for reaction with alcohol for 2. All observations can be rationalized in terms of the formation of a more stable carbocation from 2, leading to an earlier transition state, reduced nucleophilic solvation and the possibility of extensive progression to a free carbocation prior to product formation.

Correlation of the Rates of Solvolysis of 4-Morpholinecarbonyl Chloride Using the Extended Grunwald-Winstein Equation

“…Ion pair intermediate can be stabilization of the developing acylium ion by mesomeric interaction of the lone pair electrons on the nitrogen shown in Scheme 2. 19 The first contributor will be dominant, because nitrogen atom can carry a positive charge in onium-type structure than oxygen, 20 and also nitrogen atom can give better π electron donation effect than oxygen atom. In turn, this will lead to an enhanced stability for the resonance hybrid.…”

Application of theNTSolvent Nucleophilicity Scale To Attack at Phosphorus: Solvolyses ofN,N,N‘,N‘-Tetramethyldiamidophosphorochloridate

“…One can visualize that, on going to more crowded situations, solvents containing a water component are less disadvantaged than the binary TFE−ethanol mixtures. This cannot be the full story, however, because phenyl chlorodithioformate 14b and N , N -dimethylthiocarbamoyl chloride, containing the bulkier thiocarbonyl group in place of carbonyl, solvolyze in TFE−ethanol mixtures with the data from these solvents close to the correlation line. Indeed, insofar as small deviations of the N T values from the standard values occur, they are in the opposite direction from those obtained for chloroformate esters (calculated N T values of −1.45 ± 0.25 in 80T−20E and −0.70 ± 0.03 in 60T−40E).…”

Influence of Sulfur for Oxygen Substitution in the Solvolytic Reactions of Chloroformate Esters and Related Compounds

“…This is indeed the case and the ratios of the specific solvolysis rates of (CH 3 ) 2 NCSCl relative to those for (CH 3 ) 2 NCOCl, at 0.0 °C, of 120 to 344 in ethanol, methanol, and their binary mixtures with water, increasing to 448–1660 in TFE and mixtures of TFE with H 2 O or ethanol demonstrate large effects. In a Grunwald-Winstein treatment [ 19 ] using the two-term version (Equation (2)) both the l and m values are lower for the thiocarbamoyl derivative than for N , N -dimethylcarbamoyl chloride, with values of 0.29 ± 0.03 for l and 0.55 ± 0.06 for m ( R = 0.993). The l / m ratio of 0.53 is also considerably lower than the value of 0.86 for (CH 3 ) 2 NCOCl.…”

“…In addition to the derivatives of a chloroformate ester (RO(C=O)Cl) already tabulated, we can consider the replacement of the oxygen of the alkoxy group by an NR' group to give a N , N -disubstituted carbamoyl chloride, alternative naming as (dialkylamino)carbonyl chloride, and further, the influence of then replacing the remaining oxygen atom by a sulfur atom [ 19 ].…”