Direct Methylation of Primary and Secondary Alcohols by Trimethyl Phosphate to Prepare Pure Alkyl Methyl Ethers.
摘要:
Primary and secondary alcohols and diols react autocatalytically with trimethyl phosphate plus small amounts of polyphosphoric acid at 185 degrees C to give the corresponding methyl ethers. High purity and good yields are achieved when the ether is distilled from the reaction mixture as it is formed. By controlled addition even low-boiling alcohols can be methylated successfully. The reaction mechanism is undetermined. Peroxide formation in ethers is inhibited by storage over 10 molal KOH. Pure isotropic optical crystals are used for refractometer calibration. Improved physical property and NMR data (H-1 and C-13) are reported for thirteen methyl ethers. Simple two-point linear extrapolation of NMR shifts (especially C-13) to infinite dilution produces highly reproducible delta degrees-values (to 0.01 ppm or better) which uniquely characterize a molecule even when unidentified and/or not isolated from a mixture. This capability appears not to have been recognized in the literature.
Cobalt-Catalyzed Remote C-4 Functionalization of 8-Aminoquinoline Amides with Ethers via C–H Activation under Visible-Light Irradiation. Access to α-Heteroarylated Ether Derivatives
作者:Tubai Ghosh、Pintu Maity、Brindaban C. Ranu
DOI:10.1021/acs.orglett.7b03955
日期:2018.2.16
A cobalt-catalyzedselective remote C-4alkylation of 8-aminoquinoline amides via C–H activation under irradiation with a CFL lamp in the presence of eosin Y at room temperature has been achieved. A series of pharmaceutically important C-4quinoline amide-substituted ether derivatives has been obtained by this procedure. The C-4 functionalization of quinoline amides with inert ether is of much significance
Copper-catalyzed selective C_O bond formation by oxidative α-C(sp3)_H/O_H coupling between ethers and salicylaldehydes
作者:Balaji D. Barve、Yang-Chang Wu、Mohamed El-Shazly、Michal Korinek、Yuan-Bin Cheng、Jeh-Jeng Wang、Fang-Rong Chang
DOI:10.1016/j.tet.2015.02.035
日期:2015.4
Copper-catalyzedoxidativecoupling of ethers and salicylaldehydes, via the direct α-C(sp3)–H bond functionalization of ethers in the presence tert-butyl hydroperoxide as an oxidant has been explored. The corresponding acetals were selectively formed in moderate to excellent yields. The sensitive formyl group of salicylaldehydes remained intact despite the oxidative reaction conditions.
A Simple, Effective Boron-Halide Ethoxylation Catalyst
作者:Kenneth G. Moloy
DOI:10.1002/adsc.201000004
日期:2010.3.22
iodide or bromide to catalyze the ethoxylation of alcohols and phenols, giving good rates and narrow product distributions. The combined action of a weak electrophile [B(OR)3] and a weaknucleophile (halide) allows for the ethoxylation of base‐sensitive alcohols. Experiment suggests a new mechanism for this commercially important reaction proceeding through key β‐haloalkoxy intermediates.