77959-22-9Relevant academic research and scientific papers
New Heterocyclic Compounds : 5-Oxo/thio-4-aryl-2-phenylimino-1,3,4-dithiazolidines
Jadhav, R. T.,Nimdeokar, N. M.,Paranjpe, M. G.
, p. 970 - 974 (2007/10/02)
5-Oxo/thio-4-aryl-2-phenylimino-1,3,4-dithiazolidines (VI and IX) have been prepared by reaction of S-chloro-N-phenylisothiocarbamoyl chloride and triethylamine salts of arylthiocarbamic acids and aryldithiocarbamic acids respectively.VI and IX when boiled with benzylamine give the same product (XI).The structures of all these products have been assigned on the basis of chemical transformations and IR data.Probable mechanisms of these reactions are also suggested.
Mechanism of Cleavage of Carbamate Anions
Ewing, Sheila P.,Lockshon, Daniel,Jencks, William P.
, p. 3072 - 3084 (2007/10/02)
Carbamates and monothiocarbamates of basic aliphatic amines undergo rate-determining C-N cleavage after a rapid equilibrium protonation step, as shown most directly by inverse solvent deuterium isotope effects of kD/kH = 3.6-4.8 for O,O- and O,S-N-n-butylcarbamates and by rapid acid-catalyzed exchange of the NH proton of n-BuNHCOS- with kexch = 5 107 M-1 s-1.The lifetimes of substituted N-protonated carbamates have been estimated to range down to -10 s.It is concluded that general acid catalysis of the cleavage of carbamates of weakly basic anilines (α = 0.84) occurs through an enforced preassociation mechanism with hydrogen bonding to the leaving protonated nitrogen atom and C-N cleavage in the rate-determining step.There is more proton transfer in the transition state (larger α) and a smaller β1g with more basic amines and upon substitution of sulfur for oxygen.The low pKa values of N-protonated carbamates and monothiocarbamates illustrate the strong electron-accepting ability of -COO- and -COS-.
