86317-27-3Relevant academic research and scientific papers
Aminolysis of aryl chlorothionoformates with anilines in acetonitrile: Effects of amine nature and solvent on the mechanism
Oh, Hyuck Keun,Ha, Joo Suk,Sung, Dae Dong,Lee, Ikchoon
, p. 8219 - 8223 (2007/10/03)
The aminolysis of aryl chlorothionoformates (7, YC6H 4OC(=S)Cl) with anilines (XC6H4NH2) in acetonitrile at 5.0 °C has been investigated. The rates are slower than those for the corresponding reactions of aryl chloroformates (6, YC 6H4OC(=O)Cl). This rate sequence is a reverse of that for alkyl chloroformates (1 4) in water, for which rate-limiting formation of a tetrahedral intermediate, T±, is predicted. On the basis of the large negative cross-interaction constant, ρXY = -0.77, failure of the reactivity-selectivity principle, normal kH/k D values involving deuterated nucleophiles (XC6H 4ND2), and low ΔH≠ with large negative ΔS≠ values, a concerted mechanism with a four-membered hydrogen bonded cyclic transition state (11) is proposed for the title reaction series. It has been shown that the solvent change from water to acetonitrile for the aminolysis of 6 and 7 causes a mechanistic change from stepwise to concerted.
Degradation in Aqueous Solution of O-Aryl N-Arylthioncarbamates to Aryloxide Ions and Isothiocyanates. A Study of Leffler's Assumption
Hill, Stephen V.,Thea, Sergio,Williams, Andrew
, p. 437 - 446 (2007/10/02)
Rate constants for the title reaction have been measured in both forward and reverse directions leading to rates and equilibrium constants for all steps in equation (i).The effects of varying the structures of Ar and Ar' on the equilibrium and rate constants were measured; identical Leffler-Grunwald indices (α=βF/βEQ=d log k/d log K) for the addition step are observed for variation in Ar and Ar' although individual β values are markedly different.Identical α parameters arising from different substituent interaction pathways to a single bond are required if the reaction conforms to the Leffler assumption; on this basis the α parameter is considered a good measure of transition-state structure relative to reactant- and product-states for the addition reaction. 'Effective charges' on the phenolic oxygen in the thioncarbamate and its conjugate base indicate considerable C(1+)-S(1-) character in the formal thioncarbamoyl bond.
