103-93-5Relevant articles and documents
C-H Functionalization via Remote Hydride Elimination: Palladium Catalyzed Dehydrogenation of ortho-Acyl Phenols to Flavonoids
Zhao, Xiaomei,Zhou, Jiabin,Lin, Shuying,Jin, Xukang,Liu, Renhua
supporting information, p. 976 - 979 (2017/03/14)
Although deprotonation of electron-poor C-H bonds to carbon anions with bases has long been known and widely used in organic synthesis, the hydride elimination from electron-rich C-H bonds to carbon cations or partial carbocations for the introduction of nucleophiles is a comparatively less explored area. Here we report that the carbonyl β-C(sp3)-H bond hydrogens of ortho-acyl phenols could be substituted by intramolecular phenolic hydroxyls to form O-heterocycles, followed by dehydrogenation of the O-heterocycle into flavonoids. The cascade reaction is catalyzed by Pd/C without added oxidants and sacrificing hydrogen acceptors.
Lipase catalyzed esterification of cresols
Suresh Babu,Karanth,Divakar
, p. 1068 - 1071 (2007/10/03)
Esters of m- and p-cresols with organic acids having carbon chain lengths C2-C18 have been prepared by using lipases from porcine pancreas and Rhizomucor miehei. Gram level conversions are carried out under non-solvent conditions in case of shake flask experiments and continuous removal of water at bench-scale levels. Addition of 0.1 mL of 0.1M phosphate buffer at pH 7.0 to the reaction mixture shows better conversions. Optimization studies have been carried out for p-cresyl laurate synthesis using Rhizomucor miehei lipase which show a maximum conversion of 74.4 %. Better conversions are obtained with larger amounts of enzyme. Porcine pancreas lipase catalyzed synthesis of m- and p-cresyl esters show that under identical reaction conditions acids with lower carbon chain lengths (C2-C4) give ester yields above 30%, while those with longer carbon chain lengths give ester yields 30%.
