Methyl metallates production

Tracer studies with 13C showed that the carbon of methoxy species formed in CO hydrogenation appeared as the central C atom of isobutylene.531 Methoxy was shown to be reduced to surface methyl species that was transformed to surface acetyl group via insertion of CO into the methyl-metal bond. Aldol condensation of C2 oxygenates with formaldehyde affords iso-C4 products.532 Earlier results of a different approach for isosynthesis using metal-zeolite catalyst systems are summarized in a 1998 review.533... 

Metal fatigue Metal production Metallurgy Metamorphic grade Metamorphic rock Metamorphism Metamorphosis Meteorology Meteors and meteorites Methyl group Metric system Mice... 

The remaining organopotassium products (40-60%) are metallation products of 1,1-dimethylcyclopropane. 2-methyl- 2-butene and 2-methyl-1-butene in a ratio of 3.8 1.5 1 as judged by the products of protonation. 

The catalysts or catalysts precursors employed in these studies were anionic group 6 carbonyl complexes ( ) or group 8 metal carbonyl clusters (37— 0) where reaction conditions were 500 psi (CO2/H2) and 125 C. For the group 6 metal catalysts, the turn-over numbers obtained for the methyl formate production were ca. 15 using methanol as solvent for a 24 hour period. The anionic metal carbonyls examined as catalysts precursors included HM2(CO)io , HC02M(C0)5, and CH3C02M(C0)s as their PPN salts (PPN = bis(triphenylphosphine)-iminium and M Cr or W). The proposed reaction pathway is depicted in Scheme 3. 

Broaddus (13) studied extensively the metalations of the aromatic hydrocarbons benzene, toluene, ethylbenzene, cumene, terf-butylbenzene, and anisole by BuLi-TMEDA. He used a 4 1 ratio of arene to metalating agent, and he followed the reactions by gas-liquid chromatography of the methyl esters resulting from carbonation and subsequent esterification. Broaddus also concluded that reaction time has no measurable effect on the product distribution of metalated products and that rearrangement of the kinetically favored products is not significant. He further observed that the extent of ring metalation, compared with ben-... 

Hauser et al. [1] investigated the metallation of JV.JV-dimethyl benzylamine with a number of strong bases. Whereas BuLi and BuNa gave either exclusively the O-metallated or a-metallated derivative, the reaction with PhLi, PhNa, and PhK led directly to the a-metallated product. A similar result is obtained when treating the amine with BuLi t-BuOK (= BuK ) in a mixture of THF and hexane [2]. The dark-red solution thus obtained reacts very smoothly with alkyl halides even at very low temperatures. In fact, the reaction with methyl iodide may be carried out like a titration using the characteristic colour as indicator. 

The presence of heavy metals and other elements may inhibit or enhance microbiological transformations of arsenic in soil systems. It was observed that presence of phosphate and selenate causes inhibition of methylated evolution of arsenic (5,46,56). Frankenberger (57) studied the effect of 21 trace elements for their activation or inhibition on methylated arsine production by a Penicillium sp. from MMAA. Metals and metalloids at an elemental concentration of 0, 0.1, 1, 10, 100, and 1000 pM were tested for their influence on arsenic volatilization by the Penicillium sp. The effect of trace elements varied considerably depending on the speciation and concentration. At the lower elemental concentrations (0.1 and 1 pM), the metals and metalloids that stimulated arsenic volatilization were... 

A strange C-C bond breaking reaction converts the palladium duno-below into meta-dialkylbenzenes on treatment with simple alkyl halides and hydrogen in die presence of a donor ligand. No intermediates were isolated and the metal product was [PdL2] where L is DMF or methyl-isonicotinate (Scheme 15). ... 

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