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By Alkylation

Diazomethane methylation of 3-hydroxy-2,5-diisobutylpyrazine 1,4-dioxide has been shown to give the 4-methoxypyrazine 1-oxide, 2,5-diisobutyl4-methoxy-3-0X0-3,4-dihydropyrazine 1-oxide (96) (843, 980) [and some 3-methoxy-2,5-diisobutylpyrazine 1,4-dioxide (4 l)(980)] 5-s-butyl-3-hydroxy-2-isobutylpyrazine [Pg.190]

4- dioxide gave 4,6-dimethoxy-2,5-dimethyl-3-oxo-3,4-dihydropyrazine 1-oxide (97) (842). 3-Hydroxypyrazine 1-oxide in methanol reacted with diazomethane in ether to give a methyl ether which on spectroscopic evidence was assigned the structure 3-methoxypyrazine 1-oxide (108). [Pg.190]


Me3CCH2CMe2C H40H. M.p. 8l-83"C, b.p. 286-288°C. Made by alkylation of phenol. Forms oil-soluble resins with methanal (salts used as oil additives) and surfactants (with ethylene oxide). [Pg.286]

Styrene is manufactured by alkylating benzene with ethene followed by dehydrogenation, or from petroleum reformate coproduction with propylene oxide. Styrene is used almost exclusively for the manufacture of polymers, of which the most important are polystyrene, ABS plastics and styrene-butadiene rubber. U.S. production 1980 3 megatonnes. [Pg.374]

Either by alkyl groups which are designated by the letter R, which is equivalent to to give alkyl-aromatics. The prefixes ortho, meta... [Pg.6]

Refiners will turn to reformulated motor fuels where the octane number will be increased by alkylate or oxygenated compounds. It has indeed been shown for a long time that oxygenated compounds, alcohols, ethers and ketones Improved the octane number of hydrocarbon-based blends (Whitcomb, 1975). [Pg.352]

The species at the centre of tire rings is usually Si or Ge and tire bridging atom is oxygen. In one study tire peripheral hydrogens on tire phtlialocyanine molecules were replaced by alkyl groups and tire resulting polymers could be rendered soluble in ordinary organic solvents [108, 109 and 110]. Successful deposition of several of tliese materials has been achieved and different techniques were employed to study tlieir stmctural properties [109, ill, ill, ill and 1141. [Pg.2620]

Methyl and ethyl ethers of phenols are most conveniently prepared by alkylation with dimethyl sulphate and diethyl sulphate respectively in weakly alkaline solution, for example ... [Pg.665]

Cumulenic ethers with the 4-positions blocked by alkyl groups can be obtained from bis-ethers, R0-CH2C=C-C(R )(r2)0R, and sodium amide in liquid NHj, applying the... [Pg.116]

The 1,6-difunctional hydroxyketone given below contains an octyl chain at the keto group and two chiral centers at C-2 and C-3 (G. Magnusson, 1977). In the first step of the antithesis of this molecule it is best to disconnect the octyl chain and to transform the chiral residue into a cyclic synthon simultaneously. Since we know that ketones can be produced from add derivatives by alkylation (see p. 45ff,), an obvious precursor would be a seven-membered lactone ring, which is opened in synthesis by octyl anion at low temperature. The lactone in turn can be transformed into cis-2,3-dimethyicyclohexanone, which is available by FGI from (2,3-cis)-2,3-dimethylcyclohexanol. The latter can be separated from the commercial ds-trans mixture, e.g. by distillation or chromatography. [Pg.206]

Structure determination of the products obtained by alkylation was established previously by ... [Pg.37]

A-2-Thiazoline-4-ones are usually obtained by the heterocydization method (38b-388). 2 Alkylthio-4(5)-thiazolones (162) are obtained by alkylation at sulfur of rhodanine (160) in nonpolar solvent (Scheme 85). [Pg.419]

Quaternarj salts are obtained by alkylation of selenazole bases, the heterocyclic nitrogen atom playing the role of nucleophile with regard to the electrophilic carbon of the alkylating, agent. [Pg.256]

The quatemization of the nitrogen atom of the thiazole ring (the Menschutkin s reaction) by alkyl halide or methyl tosylate can be used to measure the reactivity of this atom and thus to evaluate steric and electronic effects of ring substituents. [Pg.386]

Thus the study of polymers containing thiazole rings, linked by alkyl or... [Pg.398]

Carbocations are stabilized by alkyl substituents attached directly to the positively charged carbon Alkyl groups are electron releasing sub stituents Stability increases in the order... [Pg.181]

Like carbocations free radicals are stabilized by alkyl substituents The order of free radical stability parallels that of carbocation stability... [Pg.181]

We have seen this situation before m the reaction of alcohols with hydrogen halides (8ection 4 11) m the acid catalyzed dehydration of alcohols (8ection 5 12) and m the conversion of alkyl halides to alkenes by the El mechanism (8ection 5 17) As m these other reactions an electronic effect specifically the stabilization of the carbocation intermediate by alkyl substituents is the decisive factor The more stable the carbo cation the faster it is formed... [Pg.342]

PREPARATION OF ALKYNES BY ALKYLATION OF ACETYLENE AND TERMINAL ALKYNES... [Pg.370]

Preparation of Alkynes by Alkylation of Acetylene and Terminal Alkynes... [Pg.371]

Reactions that attach alkyl groups to molecular fragments are called alkylation reactions One way m which alkynes are prepared is by alkylation of acetylene... [Pg.371]

When two positions are comparably activated by alkyl groups substitution usually occurs at the less hindered site Nitration of p tert butyltoluene takes place at positions ortho to the methyl group m preference to those ortho to the larger tert butyl group This IS an example of a stenc effect... [Pg.503]

The starting material in the example is obtained by alkyl ation of ethyl acetoacetate with allyl bromide... [Pg.896]

The small differences m basicity between ammonia and alkylammes and among the various classes of alkylammes (primary secondary tertiary) come from a mix of effects Replacing hydrogens of ammonia by alkyl groups affects both sides of the acid-base equilibrium m ways that largely cancel... [Pg.920]

A method that achieves the same end result as that desired by alkylation of ammonia but which avoids the formation of secondary and tertiary amines as byproducts is the Gabriel synthesis Alkyl halides are converted to primary alkylamines without contam mation by secondary or tertiary amines The key reagent is the potassium salt of phthal imide prepared by the reaction... [Pg.929]

The reaction of amines with alkyl halides was seen earlier (Section 22 7) as a complicat ing factor in the preparation of amines by alkylation of ammonia... [Pg.937]

Ethers are formed under conditions of the Williamson ether synthesis Methyl ethers of carbohydrates are efficiently prepared by alkylation with methyl iodide m the presence of silver oxide... [Pg.1059]


See other pages where By Alkylation is mentioned: [Pg.22]    [Pg.27]    [Pg.33]    [Pg.51]    [Pg.87]    [Pg.129]    [Pg.237]    [Pg.307]    [Pg.9]    [Pg.161]    [Pg.46]    [Pg.272]    [Pg.383]    [Pg.389]    [Pg.462]    [Pg.82]    [Pg.23]    [Pg.161]    [Pg.162]    [Pg.335]    [Pg.372]    [Pg.905]    [Pg.928]   


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Acylaminopyrazines by alkylation

Alcohols by hydrolysis of alkyl halides

Alkene Synthesis by Elimination of Alkyl Halides

Alkenes by alkylation of alkenyllithium reagents

Alkyl groups catalyzed by Lewis acids

Alkyl iodides by reaction of hydrogen iodide with

Alkylation by Conjugate Addition

Alkylation by Mannich bases

Alkylation by Unsaturated Compounds

Alkylation by alcohols

Alkylation by aldehydes

Alkylation by alkyl halides in nitromethane

Alkylation by conjugate addition reactions

Alkylation by dialkyl sulfates

Alkylation by ethyl iodide

Alkylation by free-radicals

Alkylation by means of phosphorus-containing esters

Alkylation by olefins

Alkylation by p-toluenesulfonic esters

Alkylation of Amines by Alkyl Halides

Alkylation of Benzene by Propylene to Cumene

Alkylation of Carbon Nucleophiles by Conjugate Addition

Alkylation of Carbon by Conjugate Addition

Alkylation of nitrogen compounds by sulfuric esters

Alkylation, by means of phosphoruscontaining esters

Alkylation, by oxonium salts

Alkylations by Unsaturated Compounds

Alkylations, catalyzed by NHCs

Alkynes alkylation by organoboranes

Amine Synthesis by A-Alkylation

Amines by reductive alkylation

Amines from by reductive alkylation

Average alkyl chain length by H-NMR

By Alkyl Radicals

By Alkylation of Hydroxypyrazines

By Direct Alkylation or Arylation

By Direct C-Alkylation

By Elimination of Functionality from Substituted-Alkyl Substituents

By Interconversion of Alkyl or Aryl Substituents

By Interconversion of Simple Alkyl Substituents

By Oxidation of Alkyl-, Styryl-, Hydroxyalkyl-, and Fused Pyrazine Systems

By Reaction with Alkyl Halides

By Reaction with Metals and Alkylating Agents

By reduction of alkyl halides

By the activation of alkyl nitro compounds

Conjugate addition followed by alkylation

Elimination Reactions by Sml2 Reduction of Alkyl Halides

Enantioselective reactions alkylation of alkynes by organoboranes

Ethylbenzene by Alkylation of Benzene with Ethylene

Ethylbenzene, by alkylation of benzene

Example Optimization of Friedel-Crafts alkylation by the Basic simplex method

Fischers Base Salts by Alkylation of Indolenines

Free radical stabilization by alkyl groups

From Alkyl Complexes by a-Abstraction

From Alkyl Halides by Dehydrohalogenation

Imines (cont formation by rearrangement of alkyl nitrenes

In tnfluoroacetic acid of alkyl halides by Nphenyltnflamide

Isobutane Alkylation by 2-Butylene

Ketones, preparation by alkylation

Ketones, preparation by alkylation 2,4-pentanedione and cleavage

Ketones, preparation by alkylation acids and iron powder

Ketones, preparation by alkylation phosphorus oxychloride to form

Ketones, preparation by alkylation reaction with dimethylformamide and

Mannich Reaction Alkylation of Enols by Iminium Ions

Metal-free Alkylations by Acyl Halides on Polymeric Supports

Modification of 3-alkyl substituents by nucleophilic substitution

N-Methylarylamines, preparation by reductive alkylation

Oxidation, of alkyl radicals by copper

PEGylation by Alkylation

Phosphine alkylation by a -functionalized alkyl halide

Piperazinediones by Acid Cyclative Cleavage Method A, including Reductive Alkylation

Preparation of Alkyl- and Arylpyrazine A-Oxides by Oxidation

Preparation of Amines by Reductive Alkylation

Quaternization, by alkyl halides

Reductive alkylation of methylamine by 2,3-dimethoxybenzaldehyde

Replacement of methylene hydrogen by alkyl

Reversible Alkylation of DNA by Quinone Methide Bioconjugates

Reversible Alkylation of DNA by Quinone Methides

Ruthenium Olefin Metathesis Catalysts Supported by Cyclic Alkyl Aminocarbenes (CAACs)

Sulfhydryls alkylation by maleimides

Synthesis of Alkyl Complexes by Other Methods

Synthesis of Alkyl Complexes by Transmetallation

Synthesis of Amines by Alkylation

The Alkylation of Benzene by Acylation-Reduction

Yields, by alkylation

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