Methyl phenyl carbonate

Poly[thio bis(4-phenyl)carbonate] Poly[2,2-propane bis 4-(2-methyl)phenyl carbonate] 383 368/418 513 443 1.5783 ... 

Carbene carbon. Carbonyl carbon. COD = 1.5-cyclooctadiene. CioHja = cyclopen tad iene dimer. Carbon trans to phosphorus or arsenic. Carbon trans to halogen or methyl. Phenyl carbon. Cyanide carbon. 

Structures of [alkali metal phenoxide C02] complex In the Kolbe-Schmitt reaction, phenyl carbonate (I) was originally proposed as the intermediate[2], but infrared absorption (i.r.) spectra of the intermediate showed a band at 1684 cm which disagrees with I, because an absorption band at 1754 cm of methyl phenyl carbonate is not much different from 1748 cm for dimethyl carbonate.[3] Therefore, the carbonyl of the complex might be in the structures such as (II) - (IV). 

Methyl phenyl carbonates with benzyl ehloride and (n-Bu)4PBr heated at 150° (3h) gave benzyl phenyl ether... 

We have explored the compounds by which the wettability of the electrolyte solutions is improved. The contact angle between PC and gr hite was dependent on the kind of graphite, and the addition of methyl phenyl carbonate (MPC) reduced it, as... 

In particular, the dimethyl cyclohexanone ketal also has been reacted with ethyleneglycol to afford a cycHc carbonate and cyclohexanone [112], plus methanol (Scheme 1.16). The use of DCC as water trap deserves comment A detailed study has shown that it is a promoter of the carboxyiation in addition to being a simple water removal agent Combining experimental studies and DFT calculations, the reaction mechanism has been completely elucidated, as shown in Scheme 1.17 [113]. Several carbonates have been produced with very high yields (90-96%) and selectivity (dose to 100%). The latter is highly influenced by the temperature as above 335 K the favored reaction is the formation of carbamate (Scheme 1.17 A). With DCC, using methanol and phenol it has been possible to produce the mixed methyl-phenyl-carbonate, (MeO)(PhO)CO [113]. 

Early Synthesis. Reported by Kolbe in 1859, the synthetic route for preparing the acid was by treating phenol with carbon dioxide in the presence of metallic sodium (6). During this early period, the only practical route for large quantities of sahcyhc acid was the saponification of methyl sahcylate obtained from the leaves of wintergreen or the bark of sweet bitch. The first suitable commercial synthetic process was introduced by Kolbe 15 years later in 1874 and is the route most commonly used in the 1990s. In this process, dry sodium phenate reacts with carbon dioxide under pressure at elevated (180—200°C) temperature (7). There were limitations, however not only was the reaction reversible, but the best possible yield of sahcyhc acid was 50%. An improvement by Schmitt was the control of temperature, and the separation of the reaction into two parts. At lower (120—140°C) temperatures and under pressures of 500—700 kPa (5—7 atm), the absorption of carbon dioxide forms the intermediate phenyl carbonate almost quantitatively (8,9). The sodium phenyl carbonate rearranges predominately to the ortho-isomer. sodium sahcylate (eq. 8). 

Complexes 79 show several types of chemical reactions (87CCR229). Nucleophilic addition may proceed at the C2 and S atoms. In excess potassium cyanide, 79 (R = R = R" = R = H) forms mainly the allyl sulfide complex 82 (R = H, Nu = CN) (84JA2901). The reaction of sodium methylate, phenyl-, and 2-thienyllithium with 79 (R = R = r" = R = H) follows the same route. The fragment consisting of three coplanar carbon atoms is described as the allyl system over which the Tr-electron density is delocalized. The sulfur atom may participate in delocalization to some extent. Complex 82 (R = H, Nu = CN) may be proto-nated by hydrochloric acid to yield the product where the 2-cyanothiophene has been converted into 2,3-dihydro-2-cyanothiophene. The initial thiophene complex 79 (R = R = r" = R = H) reacts reversibly with tri-n-butylphosphine followed by the formation of 82 [R = H, Nu = P(n-Bu)3]. Less basic phosphines, such as methyldiphenylphosphine, add with much greater difficulty. The reaction of 79 (r2 = r3 = r4 = r5 = h) with the hydride anion [BH4, HFe(CO)4, HW(CO)J] followed by the formation of 82 (R = Nu, H) has also been studied in detail. When the hydride anion originates from HFe(CO)4, the process is complicated by the formation of side products 83 and 84. The 2-methylthiophene complex 79... 

Katritzky and co-workers studied the mechanism of this reaction in detail. His work involved a NMR study of 16 reactions of methyl-, phenyl-, 1,2-dimethyl-, and l-methyl-2-phenylhydrazine with /3-keto esters. In many cases starting materials, intermediates, and products were detected simultaneously. Most reactions proceed by nucleophilic addition of the less hindered hydrazine nitrogen atom to the keto carbon of the keto ester. For example, the pathway given in Scheme 3 for the reaction of methyl 3-oxobutanoate 9 with methyl- or phenyUiydrazine 2 (R = Me or Ph) was found to be dominant. The initially formed addition product 10 dehydrates to hydrazone 11, which then isomerizes to hydrazone 12. Intermediate 12 then cyclizes to pyrazol-3-one 13, which tautomerizes to the kinetically more stable pyrazol-3-otie 14 [87JCS(P2)969]. 

Phenyl radical, side by side with methyl radical, carbon dioxide and methyl benzoate, was also stabilized in an inert matrix as a product of UV photolysis of acetyl(benzoyl)peroxide [112] (Pacansky and Brown, 1983). Of nine IR bands of the radical C6H5, intense absorption at 710 cmwhich was shifted to 519 cm for the deuterium-labelled radical C Ds, has been assigned to out-of-plane CH deformation. The bands of the phenyl radical... 

The biotransformation of methyl phenyl phosphonate to benzene by K. pneumoniae (Cook et al. 1979) (Figure 2.7a). Further examples of the cleavage of the carbon-phosphorus... 

Organic hydroperoxides have also been used for the oxidation of sulphoxides to sulphones. The reaction in neutral solution occurs at a reasonable rate in the presence of transition metal ion catalysts such as vanadium, molybdenum and titanium - , but does not occur in aqueous media . The usual reaction conditions involve dissolution of the sulphoxide in alcohols, ethers or benzene followed by dropwise addition of the hydroperoxide at temperatures of 50-80 °C. By this method dimethyl sulphoxide and methyl phenyl sulphoxide have been oxidized to the corresponding sulphone in greater than 90% yields . A similar method for the oxidation of sulphoxides has been patented . Unsaturated sulphoxides are oxidized to the sulphone without affecting the carbon-carbon double bonds. A further patent has also been obtained for the reaction of dimethyl sulphoxide with an organic hydroperoxide as shown in equation (19). 

Snyder et al. [253] compared supercritical fluid chromatography with classical sonication procedures and Soxhlet extraction for the determination of selected insecticides in soils and sediments. In this procedure the sample was extracted with carbon dioxide modified with 3% methanol at 350atm and 50°C. An excess of 85% recovery of organochlorine and organophosphorus insecticides was achieved. These included Dichlorvos, Diazinon, (diethyl-2-isopropyl-6-methyl 4-pyrimidinyl phosphorothioate), Ronnel (i.e. Fenchlorphos-0,0 dimethyl-0-2,4,5-trichlorophenyl phosphorothioate), Parathion ethyl, Methiadathion, Tetrachlorovinphos (trans-2-chloro-l-(2,4,5 trichlorophenyl) vinylchlorophenyl-O-methyl phenyl phosphoroamidothioate), Endrin, Endrin aldehyde, pp DDT, Mirex and decachlorobiphenyl. 

T. M. Kitson, The Action of Cytoplasmic Aldehyde Dehydrogenase on Methyl p-Nitro-phenyl Carbonate and p-Nitrophenyl Dimethylcarbamate , Biochem. J. 1989, 257, 579-584 T. M. Kitson, K. E. Kitson, A Comparison of Nitrophenyl Esters and Lactones as Substrates of Cytosolic Aldehyde Dehydrogenase , Biochem. J. 1996, 316, 225-232 T. M. Kitson, K. E. Kitson, Studies of the Esterase Activity of Cytosolic Aldehyde Dehydrogenase with Resorufin Acetate as Substrate , Biochem. J. 1997, 322, 701-708. 

Unsubstituted cycloamyloses have been used to catalyze a number of reactions in addition to acyl group transfer. Brass and Bender (8) showed that cycloamyloses promoted phenol release from diphenyl and bis(p-nitro-phenyl) carbonates and from diphenyl and bis(m-nitrophenyl)methyl phos-phonates. Breslow and Campbell (10,11) showed that the reaction of anisole with HOCL in aqueous solution is catalyzed by cyclohexaamylose and cycloheptaamylose. Anisole is bound by the cyclodextrins and is chlorinated exclusively in the para position while bound. Cycloheptaamylose has been used to promote regiospecific alkylation followed by the highly selective oxidation shown in reaction (3) (95). In addition cycloheptaamylose effec-... 

Electrochemical reduction of aryl sulphones in methanol leads to cleavage of one carbon-sulphur bond in a two-electron process. Alkyl aryl sulphones with an electron donating substituent in the aryl ring give the arenesulphinic acid and an alkane [68, 69]. Methyl phenyl sulphone and alkyl aryl sulphones with an electron withdrawing substituent in the aryl ring are cleaved to the substituted arene and the alkylsulphinic acid [70], see Scheme 5.2. In addition, a bulky orfAo-substituent such as tert.-butyl favours cleavage to the arene and alkanesulphinic acid [71]. 

Case I. First of all, we systematically introduced perturbation at coupled ff-systems (e.g. ethylene, butadiene, hexatriene and combinations of them) by substituting hydrogen for functional groups (classified by K. N. Houk as C-, Z- and X-substituents ), especially by methyl phenyl and carboxylic ester groups. We have so far introduced perturbations in the rr-system by replacing carbon atoms by heteroatoms (N and 0) in the rr-system skeleton. 

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