Ethane alkylation with

Synthesis ofp-Ethyltoluene. j )i7n7-Ethyltoluene, the feedstock for j )-methylstyrene, is difficult to separate from the products of toluene alkylation with ethane using conventional acidic catalysts. The unique configurational diffusion effect of ZSM-5 permits -dialkylbenzenes to be produced in one step. In the alkylation of toluene with ethene over a chemically modified ZSM-5, -ethyltoluene is obtained at 97% purity (58). 

Pi peridinobenzimidazole also serves as starting material for the antipsychotic agent halopemide (69). In the absence of a specific reference, one may speculate that the first step involves alkylation with bromochloro-ethane to give halide The chlorine may then be converted to the primary amine by any of several methods such as reaction with phthalimide anion followed by hydrazinolysis. Acylation with j -fluorobenzoyl chloride then gives the desired product. 

The unique feature about anionic polymerization of diene to produce homopolymer was that the microstructure of the homopolymer could be altered and changed at will to produce unique physical and chemical properties. These microstructural changes can be introduced before, after or during the polymerization. For example, chelating diamines, such as tetramethyl ethylene and diamine (TMEDA) (18), with the alkyl-lithium catalyst have been used to produce polymer with 80 1,2 addition products, while the use of dipiperidine ethane (DPE),with same catalyst has produced polybutadiene with 100 1,2 addition product. 

Synthesis The cyclization of ethyl isocyanate with sodium azide by means of AICI3 in refluxing THF gives 1 -ethyl-1,4-dihydro-5H-tetrazol-5-one, which is alkylated with 1-chloro-2-bromo-ethane in the presence of Na2CC>3 and Kl in refluxing 4-methyl-2-pentanone to afford 1-ethyl-4-(2-chloroethyl)1,4-dihydro-5H-tetrazol-5-one i (Janssen (Janssen), 1978 Janssens et al., 1986 Hopkins, 1981 Kleemann et al., 1999). 

The main products formed by the catalytic alkylation of isobutane with ethylene (HC1—AICI3, 25-35°C) are 2,3-dimethylbutane and 2-methylpentane with smaller amounts of ethane and trimethylpentanes.13 Alkylation of isobutane with propylene (HC1—AICI3, — 30°C) yields 2,3- and 2,4-dimethylpentane as the main products and propane and trimethylpentanes as byproducts.14 This is in sharp contrast with product distributions of thermal alkylation that gives mainly 2,2-dimethylbutane (alkylation with ethylene)15 and 2,2-dimethylpentane (alkylation with propylene).16... 

Stereoselective allylic alkylations have been carried out with the aid of palladium catalysts. The 17-(Z)-ethylidene groups of steroids (obtained from the ketones by Wittig olefination) form n-allyl palladium complexes in the presence of copper(n) salts (B.M. Trost, 1974, 1976). Their alkylation with dimethyl malonate anions in the presence of 1,2-ethane-diylbis[diphenylphosphine] (— diphos) gives a reaction exclusively at the side chain and only the (20S) products. If one starts with the endocyclic 16,17 double bond and replaces an (S)-20-acetoxy group by using tetrakis(triphenylphospbine)palladium,the substitution occurs with complete retention of configuration, resulting from two complete inversions (B.M. Trost, 1976). 

Viridifloric /3-lactone, 143, has been identified as one of the pheromone components of a complex mixture of volatiles released by the pheromone glands of the male Idea leuconoe butterfly during courtship <1996BMC341>. A racemic mixture of both diastereoisomers was synthesized in four steps from the dilithio salt of 3-methylbutyric acid 144 alkylation with ethanal, dehydration of the secondary alcohol with phosphorus pentoxide, dihydroxylation of the C-C double bond with osmium tetraoxide, and finally formation of the /3-lactone by cyclization with sulfonyl chloride. By comparison with the sample isolated from I. leuconoe, the absolute configuration was established to be (2V,3V)-2-hydroxy-2-(l-methylethyl)-3-butanolide 143. 

Carbon-11 Flumazenil, 6586,87, and the iodine-123 labelled BZP antagonist iomazenil 6688 have found applications with human subjects86-88. Fluorine-18 labelled ligands FEF, 67, and FEI, 68, have been synthesized89 (equation 40) from the corresponding nor compounds 69 and 70 via alkylation with l-fluoro-2-tosyl ethane in 25-30% r.y. and specific activity > 1000 Ci mmol 1 within 90 min (overall reaction time). 

Sublimation of tetraneopentyl zirconium onto the surface of silica dehydroxylated at 500 °C results in the electrolytic cleavage of one Zr-C bond by a surface proton, with the formation of the tris neopentyl zirconium [Si]-0-Zr(CH2CMc3)3 grafted species. Reaction of this supported Zr alkyl with hydrogen at 150°C leads to the formation of a zirconium hydride. Interestingly, this reaction does not yield neopentane, but rather the formation of methane and ethane are observed. These products are in fact the result of the hydrogenolysis of evolved neopentane catalyzed by the silica-supported zirconium hydride. ... 

Ipatieff and coworkers carried out the first alkylation with alkenes and branched and normal chain alkanes (except methane and ethane) in the presence of AlCb as the catalyst. The sulfuric acid catalyzed alkylation reaction of arenes and isoalkanes, developed in 1938, is a still widely used industrial process to produce alkylates with high octane numbers. For synthetic applications, however, Friedel-Crafts-type alkylations of alkenes and alkanes have limited value since they tend to give mixtures of products, including oligomers of alkenes. ... 

Low-valent complexes of Mo and W undergo photochemistry, e.g., the Nj complexes M(N2)2(dppe)2 [M = Mo or W, dppe = l,2-bis(diphenylphosphino)ethane] react with alkyl bromides to form alkyldiazenido complexes, e.g. ... 

Ethane Alkylation of benzene with ethylene and propylene Used Benzene 0-35864 0-4008 2-007 2-2382... 

Benzene alkylation with ethane into ethylbenzene is possible over a Pt/H-MFI bifunctional... 

The deactivation of the Pt/H-MFI catalyst in the reaction of benzene alkylation with ethane proceeds in two modes [74], The first mode corresponds to the selective deactivation of the Pt sites, which are highly active in the hydrogenolysis reactions. This deactivation occurs during the first 4h of the catalyst operation and results in the significant enhancement of the selectivity to ethylbenzene. The second, much slower, deactivation process is observed during tens of hours and is responsible for the deactivation of Pt and acid sites with similar rates. 

Ethane tetracarboxylic ethyl ester can be regarded as composed of two malonic ester residues, each acting as a mono-alkyl substituent to the other. The two remaining hydrogen atoms therefore still retain acidic properties, and consequently the ester gives with sodium ethoxide a di-sodium derivative. 

ALKYLATION OF ALIPHATIC COMPOUNDS The first reported alkylation of branched-chain alkanes by ethylene, over aluminum chloride (69), made it possible to alkylate alkanes (except methane and ethane) with straight chain or branched alkenes. 

When usiag HF TaF ia a flow system for alkylation of excess ethane with ethylene (ia a 9 1 molar ratio), only / -butane was obtained isobutane was not detectable even by gas chromatography (72). Only direct O -alkylation can account for these results. If the ethyl cation alkylated ethylene, the reaction would proceed through butyl cations, inevitably lea ding also to the formation of isobutane (through /-butyl cation). 

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