Alkyl Methyl Research Articles

Excess enthalpies of binary mixtures containing halothane + methyl alkyl ketones

Molar excess enthalpies H E of binary liquid systems of halothane (2-bromo-2-chloro-1,1,1-trifluoroothane)+five methyl alkyl ketones (2-alkanones) have been determined with a flow microcalorimeter at 298.15 K and at atmospheric pressure in the entire composition range. The data were correlated by means of the Redlich-Kister expression. All these mixtures are strongly exothermic with a minimum of H E of ca. -2900 J mol -1 at nearly equimolar composition

N-Dealkylation-N-nitrosation of tertiary aromatic amines by N-butyl nitrite

N,N-Dialkyl aromatic amines with a variety of ring substituents are N-dealkylated and N-nitrosated efficiently by n-butyl nitrite/ammonium chloride/water at reflux temperature. Ring nitrosation was never observed, but minor amounts of m- and p-nitro amines and/or nitrosamines were formed in some cases. Ring nitration is rather a reaction of the initial substrate than a process occurring on formed nitrosamines. The leaving propensities of the initial N-substituents to yield nitrosamines were in the order benzyl methyl alkyl.

Screen of five alkyl carbamates for initiating and promoting activity in rat liver

Five alkyl carbamates, methyl, ethyl, propyl, hydroxypropyl and ethylhexyl, were tested for initiating and promoting activity in rat liver. The test for initiating activity consisted of administering the carbamate by gavage to male Sprague-Dawley rats at either 6 or 18 h after a 2 3 partial hepatectomy. One week later, the rats received 500 ppm sodium phenobarbital in their drinking water until killed 10 weeks later. None of the carbamates at 1 5 the LD 50 induced γ-glutamyltranspeptidase (GGT)-positive foci, indicating the lack of initiating activity. The tumor promoting activity test consisted of initiation with 80 mmol/kg diethylnitrosamine administered 18 h after a partial hepatectomy. One week later, the rats received one of the the carbamates at either 1 10 or 1 20 the LD 50 5 days per week until sacrificed 10 weeks later. The alkyl carbamates increased the volume of the foci, the percent of the liver occupied by the foci, the number of foci/cm 3 (except ethylhexyl carbamate), and the number of foci/liver (except ethylhexyl carbamate). These results suggest that the alkyl carbamates are tumor promoters and not tumor initiators in rat liver.

Stereoselectivity in the enzymic oxidation of racemic alkyl methylcarbinols - a new approach to the [formula omitted]-enantiomers

The R-enantiomers of racemic alkyl methylcarbinols are oxidized specifically by fatty alcohol oxidase (FAOD) from alkane-utilizing yeasts so that the S-enantiomers can be gained in pure state. Fatty alcohol oxidase converts stereospecifically R (-)-enantiomers of alkyl methyl carbinols.

Polymerization Mechanism of Styrene Initiated by 2,2-Bis(t-butyldioxy)alkanes

Abstract The radical polymerization mechanism of styrene initiated by 2,2-bis(t-butyldioxy)alkanes (1) has been studied in benzene. The decomposition products of 1 are acetone, alkyl methyl ketone, t-butyl alcohol, and t-butyl peracetate. Styrene monomer converts to polystyrene along with styrene oxide. The peroxides 1 cleave homolytically at one of dioxy bonds to yield intermediate alkoxyl radicals with α-t-butyldioxyl group, which undergo β-scission to afford t-butyldioxyl or alkyl radicals. The resulting t-butyldioxyl radical reacts with styrene to form 2-(t-butyldioxy)-l-phenylethyl radical, which decomposes subsequently to styrene oxide and t-butoxyl radical via γ-scission. Alternatively, a part of t-butyldioxyl radical adds to styrene to afford polystyrene containing dioxy bond.

Molecular orbital calculations on methyl alkyls and hydrides used in the organometallic vapor phase epitaxy of some III–V semiconductor films. I

We report ab initio and semiempirical calculations of the equilibrium geometries, bond strengths, and vibrational spectra of NH3, PH3, AsH3, (CH3)3Al, (CH3)3Ga, (CH3)3In, N(CH3)3, P(CH3)3, As(CH3)3, and some of their derived adducts as a function of basis set and of self-consistent field approximation. We compare our results to recent IR and Raman data, and to standard thermochemical data. We obtain very good agreement with experimental geometries, good agreement with experimental bond strengths, and only fair agreement (10%–20%) with experimental vibrational spectra. We argue that this purely theoretical approach is, with qualification, appropriate for predicting thermochemical parameters for gas-phase reactions that occur in organometallic vapor phase epitaxy of III–V semiconductor thin films. We expect to make reasonable predictions for barriers to chemical reactions, while use of our predictions of free energies will probably require care.

Alkylation of Methyl Dihydrofurancarboxylates

Methyl 3-alkyl-2,3-dihydro-3-furancarboxylates were prepared by the alkylation of methyl 2,3-dihydro-3-furancarboxylate using lithium diisopropylamide as the base, and alkyl halides, acetone or benzaldehyde as the alkylating agent. Likewise alkylation of methyl 2,5-dihydro-2-furancarboxylate gave the corresponding 2-alkylated products.

Total synthesis of kanshone A, a sesquiterpene isolated from Nardostachys chinensis (Valerianaceae)

Kanshone A, isolated from Nardostachys chinensis(Valerianaceae), has been synthesized in 9 steps by stereoselective alkylation of the derivative methyl (5,5-ethylenedioxy-1,2-dimethylcyclohexyl)acetate and an intramolecular aldol cyclization followed by methylation and introduction of a double bond.

Kinetics and mechanism of oxidation of organic sulphides by lead tetraacetate

Kinetics of oxidation of thirty-three organic sulphides, comprising monosubstituted aryl methyl sulphides and alkyl phenyl sulphides, by lead tetraacetate (LTA), to yield the corresponding sulphoxides, have been studied. The reaction is first order with respect to both sulphide and LTA and is catalysed by hydrogen ions. The observed solvent effect (m= 0.90 for MeSPh) is explained by a nucleophilic attack of the sulphide sulphur on LTA yielding a polar transition state. The rates of oxidation of meta- and para-substituted phenyl methyl sulphides were correlated with Taft′s and Swain′s dual substituent parameter equations. For the para-compounds, the best correlation is obtained with σ1 and σR+; the meta-substituted compounds correlate best with σ1 and σR0 values. The reaction constants are negative. The oxidation rates of ortho-substituted compounds yield an excellent correlation with a triparametric equation involving Taft′s σ1, and σR+ parameters, and Charton′s steric parameter V. The oxidation of alkyl phenyl sulphides is susceptible to both polar and steric effects of the alkyl groups. A mechanism involving formation of a sulphonium cation, in the rate-determining step, has been proposed.

Temperature and DMSO increase the enantioselectivity of hydrolysis of methyl alkyl dimethylmalonates catalyzed by pig liver esterase

Hydrolyses of methyl alkyl dimethylmalonates catalyzed by pig liver esterase were carried out at different temperatures. At 35°C, the stereochemical yields of the half-ester product are equal to or slightly greater than those obtained at 15°C. However, stereoselectivity is higher in the presence of 25% DMSO, and temperature has no effect on the stereoselectivity of the hydrolysis reaction.

Syntheses, rate constants, and x-ray structures of alkylrhodoximes with .sigma.-donating alkyl groups methyl, ethyl isopropyl. A comparison with the analogous alkylcobaloximes, a vitamin B12 model

Syntheses, rate constants, and x-ray structures of alkylrhodoximes with .sigma.-donating alkyl groups methyl, ethyl isopropyl. A comparison with the analogous alkylcobaloximes, a vitamin B12 model

Polyoxometalate systems for the catalytic selective production of nonthermodynamic alkenes from alkanes. Nature of excited-state deactivation processes and control of subsequent thermal processes in polyoxometalate photoredox chemistry

The photooxidations of exemplary branched acyclic alkanes and cycloalkanes by a range of polyoxotungstates varying in charge density, ground-state redox potential, acidity, and other properties were examined in detail. The organic products generated in these reactions depend on the polyoxometalate used, and in particular on the ground-state redox potential of the complex. Under anaerobic conditions acyclic branched alkanes yield principally alkenes, while cycloalkanes yield principally alkenes and dimers. Alkyl methyl ketones, derived in part from reaction with acetonitrile solvent, and isomerized alkanes are produced with some alkane substrates. Under aerobic conditions, autoxidation, initiated by radicals generated in the photoinduced redox chemistry, is observed. Under aerobic conditions the polyoxotungstates with formal redox potentials more negative than {minus}1.0 V vs Ag/AgNO{sub 3}(CH{sub 3}CN), such as W{sub 10}O{sub 32}{sup 4{minus}} and W{sub 6}O{sub 19}{sup 2{minus}}, photochemically dehydrogenate branched acyclic alkanes in high selectivity to {alpha}-olefins and the least substituted alkenes, products heretofore undocumented in photooxidation reactions catalyzed by polyoxometalates.

The reactions of tellurium tetrachloride with aliphatic monoketones

AbstractThe reactions of 13 aliphatic ketones with tellurium tetrachloride has been studied with proton, carbon‐13, and tellurium‐125 NMR. Tellurium tetrachloride adds electrophilically to the α‐carbon of the enol to form ketonyl tellurium trichlorides. Unsymmetric ketones gave mixtures of isomeric ketonyl tellurium trichlorides. Steric hindrance determines which ketonyl tellurium trichlorides form. Except for the ketonyl tellurium trichloride from 2‐butanone, tellurium reacts preferentially with the least substituted α‐carbon. Six methyl alkyl ketones also yielded appreciable amounts of diketonyl tellurium dichlorides. In all diketonyl tellurium dichlorides, tellurium is bonded to less hindered methylene carbons.

Synthesis of 4-Chloro-5-cyano-2-dimethylamino-6H-1,3-oxazin-6-one from the Salts of Alkyl Dicyanoacetates and Some of Its Reactions

The salts of alkyl dicyanoacetates and methyl 3-amino-3-chloro-2-cyanoacrylate react in chloroform with N-(dichloromethylene)dimethylammonium chloride to give 4-chloro-5-cyano-2-dimethyl- amino-6H,3-oxazin-6-one. The chloro atom of this compound can be easily substituted by alcohols or amines in good yield.

A theoretical study of the proton affinities of water, alcohols, and ethers: absolute versus relative basicities

In this work we report the proton affinities (Epa) of water, seven alcohols, and seventeen cyclic and acyclic ethers, as measured by ion cyclotron resonance spectroscopy (ICR) with respect to the same ‘basicity ladder.’ The Epa for selected compounds have been calculated by MNDO, AM1, and ab initio(3-21G and, in some cases, 4-31 G*//4-31 G and 6-31 G*//6-31 G) methods. These results are used for a comparison of the various computational techniques and for the analysis of structural effects on the neutral and protonated species. Methyl and other alkyl affinities of aliphatic alcohols are determined and discussed. The experimental Epa are treated by correlation analysis methods.

Selectivity in the lactone formation via CH insertion reaction of diazomalonates

Rhodium(II)-acetate mediated intramolecular CH insertion reactions of alkyl methyl diazomalouates result in the formation of β- and γ-lactones. The selectivity depends on both the substitution pattern of insertion centers and the conformational bias of metallocarbenes.

ChemInform Abstract: A Convenient Synthesis of Diketones via Alkylation of Alkyl Methyl Ketone Dimethylhydrazones.

ChemInformVolume 20, Issue 38 Preparative Organic Chemistry ChemInform Abstract: A Convenient Synthesis of Diketones via Alkylation of Alkyl Methyl Ketone Dimethylhydrazones. M. YAMASHITA, M. YAMASHITA Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this authorK. MATSUMIYA, K. MATSUMIYA Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this authorH. MORIMOTO, H. MORIMOTO Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this authorR. SUEMITSU, R. SUEMITSU Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this author M. YAMASHITA, M. YAMASHITA Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this authorK. MATSUMIYA, K. MATSUMIYA Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this authorH. MORIMOTO, H. MORIMOTO Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this authorR. SUEMITSU, R. SUEMITSU Dep. Appl. Chem., Doshisha Univ., Kamikyo, Kyoto 602Search for more papers by this author First published: September 19, 1989 https://doi.org/10.1002/chin.198938140Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue38September 19, 1989 RelatedInformation

A Convenient Synthesis of Diketones via Alkylation of Alkyl Methyl Ketone Dimethylhydrazones

Abstract Symmetrical diketones were prepared by the reaction of the lithium salts of alkyl methyl ketone dimethylhydrazones with dibromoalkanes.

ChemInform Abstract: The Alkylation of Methyl 2‐(1‐Pyrrolyl)acetate. A New Synthetic Method of α‐Amino Acids.

AbstractThe pyrrolylacetates (I) are converted to the α‐alkyl derivatives (IIIa), (IIIb), (IIId), and (IIIe) upon lithiation and subsequent treatment with the alkyl halides (II).

Measurements and Analysis of Excess Enthalpies of Alkyl Acetates + 1‐Chloroalkanes Using the Unifac Model

AbstractMolar excess enthalpies at 298.15 K and atmospheric pressure are reported for eight binary liquid mixtures of alkyl (methyl and propyl) acetates + 1‐chloroalkanes (pentane, hexane, heptane and octane). The experimental results along with literature data of ethyl acetate with the same 1‐chloroalkanes are examined by a version of the UNIFAC model. In general, the model reproduces the experimental data within the limits of error. The maximum discrepances are observed in those mixtures where the acetate with the largest alkyl radical intervenes; however, the average overall error of the twelve systems analysed here is less than 6.5 per cent.