Harnying, Wacharee; Sudkaow, Panyapon; Biswas, Animesh; Berkessel, Albrecht published an article in 2021. The article was titled 《N-Heterocyclic Carbene/Carboxylic Acid Co-Catalysis Enables Oxidative Esterification of Demanding Aldehydes/Enals, at Low Catalyst Loading》, and you may find the article in Angewandte Chemie, International Edition.SDS of cas: 103-74-2 The information in the text is summarized as follows:
The discovery that simple carboxylic acids, such as benzoic acid, boost the activity of N-heterocyclic carbene (NHC) catalysts in the oxidative esterification of aldehydes RCHO (R = heptan-3-yl, Ph, 1-[4-(propan-2-yl)phenyl]propan-2-yl, 6-methylhept-5-en-2-yl, etc.) was reported. A simple and efficient protocol for the transformation of a wide range of sterically hindered α- and β-substituted aliphatic aldehydes/enals, catalyzed by a novel and readily accessible N-Mes-/N-2,4,6-trichlorophenyl 1,2,4-triazolium salt, and benzoic acid as co-catalyst, was developed. A whole series of α/β-substituted aliphatic aldehydes/enals hitherto not amenable to NHC-catalyzed esterification could be reacted at typical catalyst loadings of 0.02-1.0 mol%. For benzaldehyde, even 0.005 mol% of NHC catalyst proved sufficient: the lowest value ever achieved in NHC catalysis. Preliminary studies point to carboxylic acid-induced acceleration of acyl transfer from azolium enolate intermediates as the mechanistic basis of the observed effect.2-(2-Hydroxyethyl)pyridine(cas: 103-74-2SDS of cas: 103-74-2) was used in this study.
2-(2-Hydroxyethyl)pyridine(cas: 103-74-2) belongs to pyridine. Pyridine is very deactivated towards electrophilic substitution with respect to benzene. For this reason classical formylation, using methods such as the Gattermann or Vilsmeier reactions, are not generally successful. SDS of cas: 103-74-2