Aromatic ethers cleavage

Quaternary ammonium iodides have been found to improve the yield of aluminium iodide promoted aromatic ether cleavages to... 

Cleavage with hydriodic acid. Aromatic ethers undergo fission when heated with constant boihng point hydriodic acid ... 

The mixed aliphatic - aromatic ethers are somewhat more reactive in addition to cleavage by strong hydriodio acid and also by constant b.p. hydrobromio acid in acetic acid solution into phenols and alkyl halides, they may be bromi-nated, nitrated and converted into sulphonamides (Section IV,106,2). 

Acid catalyzed cleavage of aromatic methyl or ethyl ethers Quantitative methoxy group determination Also ether cleavage with tnmethylsilyl Iodide ... 

We have studied the thermal decomposition of diaryl ether in detail, since the cleavage of ether linkage must be one of the most responsible reactions for coal liquefaction among the various types of decomposition reaction and we found that the C-0 bond of polynucleus aromatic ethers is cleaved considerably at coal liquefaction temperature. 

Figure 9. Molar yields, obtained after 20 minutes at pH 3.0 with 0.13 units mL lignin peroxidase in the presence of H2O2 and veratryl alcohol, of C -Cg, B-O-4 and aromatic ring cleavage products from 4.ethoxy-3-methoxyphenylgfycerol-B-syringyl ether moieties in dehydrogenative copolymer of conifery] alcohol and 4.ethoxy 3-methoryphet lgfycerol-B-syringaresinol (54).

Figure 10. Enhancement of all l aryl ether cleavage resulting from introduction of carbonyl group into para position of aromatic ring. Unimolecular rate coefficients for 4.8 X 10 M reactants in aqueous 30% ethyleneglycol monomethyl ether containing 0.53 - 0.54 M hydroxide and 0.08 - 0.09 M bisulfide at 170 C (63).

Reaction of the iron complex salt 602 with the arylamine 921 in the presence of air led directly to the tricarbonyl(ri -4b,8a-dihydro-9H-carbazole)iron complex (923) by a one-pot C-C and C-N bond formation. Demetalation of complex 923 and subsequent aromatization by catalytic dehydrogenation afforded 3,4-dimethoxy-l-heptyl-2-methylcarbazole (924), a protected carbazoquinocin C. Finally, ether cleavage of 924 with boron tribromide followed by oxidation in air provided carbazoquinocin C (274) (640) (Scheme 5.120). 

Aromatic Ethers The molecular ion peak of aromatic ethers is prominent. Primary cleavage occurs at the bond j8 to the ring, and the first-formed ion can decompose further. Thus anisole, MW 108, gives ions of m/z 93 and 65. 

Answer Procedure XII-5 which involves a diazonium salt and a procedure involving the cleavage of an aromatic ether as illustrated below. 

The preferential cleavage of the middle of three vicinal methoxy groups with mineral or Lewis acids has been demonstrated for various aromatic alkaloidal systems (410, 411). Selective ether cleavage of mescaline and trichocereine thus... 

This work and related studies provided the basis for the stereoelectronic model for homobenzylic ether cleavage in Fig. 3.1. This model includes overlap of the benzylic carbon-carbon bond with the SOMO of the aromatic ring (structure 13), thereby stabilizing the benzylic radical upon cleavage. Additionally, overlap of a heteroatom lone pair and the benzylic o orbital was shown to be necessary for cleavage (structure 14). 

The Qaisen rearrangement of aromatic ethers can also be photoinduced, and the quantum yields of homolytic cleavage of the ArO-Y bond have been related to O-C bond orders and dissociation energy changes on excitation to the TT,TT S] state. ... 

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