121900-47-8Relevant articles and documents
On the Reaction between the N-Bromotetramethylsuccinimide-Tetrabutylammonium Tetramethylsuccinimide Complex and C-H Acidic Compounds
Eberson, Lennart,Lepistoe, Matti,Finkelstein, Manuel,Hart, Shirley A.,Moore, W. Michael,Ross, Sidney D.
, p. 666 - 684 (2007/10/02)
The reaction between the N-bromotetramethylsuccinimide-tetrabutylammonium tetramethylsuccinimide complex and C-H acidic compounds has been studied.The main pathway leads to substitution of the acidic C-H bonds at the substrate by tetramethylsuccinimido groups, as exemplified by the formation of tris(tetramethylsuccinimido)acetonitrile from acetonitrile.The reaction with acetone is ca. 105 times faster than that with acetonitrile and displays a spectacular colour phenomenon: the initially colourless solution, after a reproducible and controllable induction period, suddenly becomes intensely purple, the absorbance maximum of which signals the end of the substitution process.Approximately in parallel with the colour development is the build-up and decay of an ESR signal (a 1:2:3:2:1 quintuplet).The position of the colour maximum can be used as a kinetic probe, the inverse of which has the dimensions of a first-order rate constant.Using this parameter, it has been established that the reaction is approximately first order in acetone, has a kinetic deuterium isotope effect of ca. 5, and has a rate-determining step involving attack of base upon the substrate.The reaction is autocatalytic with respect to the primary product, N-acetonyltetramethylsuccinimide (reaction order ca. 0.5), and is catalysed by a number of added bases, corresponding to conjugated acids of pK in the range 7-23.The mechanism most probably consists of an initial attack by tetramethylsuccinimide anion upon an acidic hydrogen of the substrate, followed by bromination of the enolate ion by the N-bromo imide.The bromo derivative reacts rapidly with tetramethysuccinmide anion to give the substitution product.The purple colour and the ESR signal are due to species originating from further reactions of the primary products.
