93979-12-5Relevant academic research and scientific papers
The Reaction of Trihalgenomethyl Anions with Carbonyl Compounds: Competitive Reactivity Comparisons and Applications to the Synthesis of α-Trihalogenomethyl Alcohols
Atkins, Paul J.,Gold, Victor,Wassef, Wasfy N.
, p. 1247 - 1252 (2007/10/02)
Trihalogenomethyl anions, generated by decarboxilation of trichloro- and tribromo-acetic acid in dimethyl sulphoxide solution, react with added aldehydes.In the presence of 1,3,5-trinitrobenzene, the reaction with aldehydes competes with the formation of the coloured Meisenheimer adduct.The reduction in absorbance from the value in the absence of aldehyde has been used tomeasure the reactivity of trihlogenomethyl anions towards a series of aldehydes relative to their reactivity towards trinitrobenzene.For 4-substituted benzaldehydes, the reactivities obey a linear p?- relationship.The most reactive aldehyde used is only two times less reactive towards CCl3(1-) or CBr3(1-) than hydrogen ions, and it is concluded that, in dimethyl sulphoxide solutions, the reaction between trichloromethyl anions and hydrogen ions is not encounter-controlled.The reactions with aldehydes have been used to prepare several new compounds of the formula RCH(OY)CX3 where R = aryl or pyridyl, X = Br or Cl, and Y = H or COCH3.
KINETICS OF THE DECOMPOSITION OF 1-ARYL-2,2,2-TRIHALOGENOETHANOLS IN AQUEOUS BASE
Lins, Hilvania Silva e,Nome, Faruk,Rezende, Marcos Caroli,Sousa, Iolanda de
, p. 1521 - 1526 (2007/10/02)
The decomposition of several 1-aryl-2,2,2-trichloro- and 1-aryl-2,2,2-tribromo-ethanols in aqueous base is studied.The title compounds yield the corresponding benzaldehydes and the halogenoform with base.The kinetics are compatible with an (E1cB)R mechanism.Values for the rates of collapse of the intermediate alkoxides and for the pKa values of all ethanols are estimated.Electron-donating substituents on the ring facilitate decomposition and decrease the acidity of the ethanols.Solvent isotope effects, kH2O/kD2O, for the reactions are small.The absence of mandelic acid derivatives among the products, in apperent disagreetment with other related studies, is discussed and justified in the light of a scheme which reconciles previous conflicting observations found in the literature.
