6425-12-3Relevant articles and documents
Aerial oxidation of 2,2-dibromo-1-aryl and heteroaryl ethanones: A facile synthesis of aryl and heteroaryl α-keto amides
Shanmugapriya,Shankar,Satyanarayana,Dahanukar, Vilas H.,Kumar, U. K. Syam,Vembu
scheme or table, p. 2945 - 2950 (2009/06/25)
The aerial oxidation of various 2,2-dibromo-1-aryl and heteroaryl ethanones to α-keto amides in the presence of air or oxygen and secondary amines are described. The reaction provides α-keto amides in moderate to good yields. The versatility of the reacti
Acidities and Homolytic Bond Dissociation Energies of the Acidic C-H Bonds in Radical Cations
Zhang, Xianman,Bordwell, F. G.
, p. 4163 - 4168 (2007/10/02)
The homolytic bond dissociation energies (BDEHA+*) of the acidic C-H bonds in radical cations of the type HA+* have been estimated by using the equation BDEHA+* = BDEHA + 23.1ox(A*) - Eox(HA)>.The BDEHA values of the acidic H-A bonds in neutral molecules were estimated from pKHA and Eox(A-) values in DMSO.Most Eox(A-) and Eox(A*) values were obtained from the reversible oxidation potentials of the conjugate bases of HA, and most Eox(HA) values were obtained from the irreversible oxidation potentials of the neutrals by cyclic voltammetric measurements.The method has been applied to obtain BDEHA+* values for thirteen 9-(dialkylamino)fluorenes, two 2-benzoyl-N,N'-dialkylperhydropyrimidines, two α,α-bis(alkylamino)acetophenones, three triphenylmethanes, two diphenylmethanes, 9,10-dihydroanthracene, four xanthenes, toluene, four fluorenes, and three arylacetonitriles. ( The acidities of the corresponding radical cations have also been estimated.) For most of the carbon-centered radical cations stabilized by one or two adjacent dialkylamino groups, the BDEHA+* values were estimated to be in the 22 - 40 kcal/mol range: i.e., they are 30 - 50 kcal/mol lower than the corresponding BDEHA values in the neutral parents.These relatively low BDEHA+* values were correlated with the stabilities of the cations formed in reactions of the type HA+* -> H* + A+.On the other hand, the BDEHA+* values for substituted aromatic hydrocarbons were found to be controlled primarily by the stabilities of the radical cations, HA+*, rather than by the stabilities of the product cations.Aromatic hydrocarbons containing two or more aryl groups usually gave radical cations with BDEHA+* values in the 30 - 40 kcal/mol range whereas those with only one aryl group gave BDEHA+* values in the 40 - 50 kcal/mol range.