Alkyl Acetates Research Articles

Coordination Behavior of ω-(Trichlorostannyl)alkyl Acetates, CH3COO(CH2)nSnCl3 (n = 3−5): A Solution and Solid-State Multinuclear NMR and AM1 Quantum-Chemical Study

The coordination behavior of three ester-functionalized monoorganotin trichlorides of the type ω-(trichlorostannyl)alkyl acetate, CH3COO(CH2)nSnCl3 (n = 3−5), has been investigated by multinuclear solid- and solution-state NMR, as well as AM1 quantum-chemical calculations. The data reveal basically the existence of a fast equilibrium between two species involved respectively in an intramolecular and intermolecular donor-acceptor interaction between the ester function and the tin atom. In the n = 3 case, the species involving the intramolecular interaction is by far the dominant one, with a coordination from the alkoxy oxygen atom to the tin atom, resulting in an interaction of the type −CH2O(Ac)→SnCl3 (Ac = CH3CO−). In contrast, for the n = 4 and 5 cases, the species involving the intermolecular interaction prevails, resulting in (cyclo)dimeric or oligomeric species displaying coordinations from the carbonyl oxygen atom to the tin atom of the type −CH2OC(CH3)O→SnCl3.

Unexpected alkylation reaction of amines, acids and phenols by alkyl (triphenylphosphoranylidene)acetates

Reaction of methyl (triphenylphosphoranylidene)acetate in methanol with primary and secondary amines led to N-methylated derivatives. Similarly this mixture reacted with acids, phenol and phthalimide to afford methyl esters, anisole and N-methylphthalimide respectively. Treatment of ketolactam 2 by this mixture under high pressure activation gave the rearranged quinolinone 5.

Partial Molar Volumes of Alkyl Acetates in Water

The densities of dilute aqueous solutions of eight alkyl acetates (methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl acetates) were measured at 5, 15, 25, 35, and 45 °C by means of a vibrating tube densimeter. The limiting partial molar volumes and its temperature dependences for the alkyl acetates in water were estimated and compared with those for more hydrophilic solutes, alcohols, reported previously. The results were discussed in terms of the effects of chain length and chain branching of alkyl residues on the solute−solvent interactions.

A Reagent for Selective Deprotection of Alkyl Acetates

The use of magnesium methoxide for selective deprotection of alkyl esters is described. By adjusting the equivalents of the magnesium methoxide reagent, it is possible to selectively cleave primary acetate in the presence of secondary and tertiary acetate and to cleave secondary acetate in the presence of tertiary acetate. A high selectivity can also be obtained for the same primary acetates if the β-positions of the acetates render a different steric bulkiness. This mild reagent has been successfully applied to the selective deprotection of many natural-occurring molecules including hydroxycitronnellol diacetate, trans-sobrerol diacetate, betulin diacetate, and baccatin III.

Highly Stereoselective Aldol Reactions of Lithium Ester Enolates with (RS)-2-(p-Tolylsulfinyl)cyclohexanones

Aldol reactions lithium alkyl acetates (LiCRR‘‘CO2R‘) with (RS)-2-(p-tolylsulfinyl)cyclohexanone (1) (as an epimeric mixture at C-2) take place with very efficient control of the configuration at the tertiary hydroxylic carbon (C-1). Stereoselectivity becomes complete if R and/or R‘‘ are not hydrogen. Only carbinols derived from (S2,RS)-1 epimer were obtained, the major ones being those exhibiting S configuration (opposite to that of the sulfur) at the hydroxylic carbon. When LiCHRCO2R‘ is used, mixtures of the two epimers at the new stereogenic center C-1‘ are obtained (∼10−82% de), their proportion being dependent on the size of R. The use of lactone enolates avoids the formation of epimeric mixtures, affording only one diastereoisomer with an (R3‘,S1,S2,RS) configuration at the four adjacent chiral centers. Tricoordinated lithium species, which involve the enolate and the sulfinyl and carbonyl oxygens of the substrates, are invoked to explain the stereoselectivity observed in these aldol reactions with sulfinyl ketones as electrophiles.

Speed of Sound, Isentropic Compressibility, Viscosity, and Excess Volume of Binary Mixtures. 1. Alkanenitriles with Alkyl Acetates

The density ρ, speed of sound u, and viscosity η of eight binary mixtures of ethanenitrile and propanenitrile with methyl acetate, ethyl acetate, and butyl acetate and of adiponitrile with ethyl acetate and butyl acetate have been measured at 303.15 K. The isentropic compressibility K S , excess volume V E , and excess isentropic compressibility K S E have been calculated therefrom. The values of V E and K S E are explainable by considering the varying extent of interactions and the difference in free volumes between unlike components.

Physical-chemical-activity relationship of organic solvents: Effects on Na +-K +-ATPase activity and membrane fluidity in mouse synaptosomes

Physical-chemical-activity relationship of aromatic hydrocarbons ( n = 10) and alkyl acetates ( n = 16) with respect to their in vitro effects on synaptosomal membranes was studied. Na +-K +-adenosine triphosphatase (Na +-K +-ATPase) activity and membrane fluidity, which was determined using the fluorescence probe 1,6-diphenyl-1,3,5-hexatriene, were used as potential indicators of neuronal cell toxicity. The potency of inhibition for the enzyme (IC 50), the potency of increasing membrane fluidity (IC 12.5), and n-octanol/water partition coefficient (P) were all determined experimentally for 26 solvents. Correlation analyses were made on aromatic hydrocarbons and on alkyl acetates. There were linear relationships between log P and pIC 50 (log1/IC 50) values, and between log P and pIC 12.5 (logl/IC 12.5) values, indicating that the hydrophobicity of the solvents determines their toxic ability to affect membrane environment; the more hydrophobic the solvents are, the more toxic they are. A direct linear relationship between Na +-K +-ATPase activity pIC 50 and membrane fluidity pIC 12.5 values was also shown. This predictive correlation suggests a similar mechanism of membrane surface interaction govering both processes that are common to the test solvents. The present results confirm the importance of the lipid environment of neuronal membranes in maintaining the normal function of membrane-bound protein.

Borohydride exchange resin; selective removal of the acetyl groups from aryl acetates

Borohydride exchange resin exhibits high selectivity in the removal of acetyl groups only from aryl acetates, however, no deacylation being observed for alkyl acetates.

VE of mixtures containing alkyi acetate, or ethyl alkanoate, or ethyl bromoalkanoate with n-hexane

Abstract Oswal, S.L., Oswal, P. and Dave, J.P., 1994. V E of mixtures containing alkyl acetate, or ethyl alkanoate, or ethyl bromoalkanoate with n -hexane. Fluid Phase Equilibria , 98: 225-234. Excess volumes, V E , have been determined from density measurements using a vibrating tube densimeter (DMA 60/602) at 303.15 K for ten binary mixtures of ethyl acetate, ethyl propionate, ethyl butyrate, amyl acetate, decyl acetate, dodecyl acetate, ethyl-2-bromopropionate, ethyl-3-bromopropionate, ethyl-2-bromobutyrate and ethyl-4-bromobutyrate with n -hexane. The molecular size of alkanoate and the position of the bromine atom in bromoalkanoate has the predominant effect on V E . The experimental results have also been analysed using the Prigogine-Flory-Patterson theory employing both the van der Waals and the Lennard-Jones energy models.

Catalytic Conversion of Alkyl Acetate into Alkene and Acetic Acid over Iron(III) Ion-Exchanged H-Mordenite

Abstract The iron(III) ion in H-mordenite was found to act as a very strong oxidizing agent. It accelerates the conversion of alkyl acetate into alkene and acetic acid by withdrawing an electron from the coordinated alkyl acetate. It also oxidizes water into proton and oxygen, and benzene into benzene radical cation.

ChemInform Abstract: Condensation of Polyfluoroalkyl Phenyl Ketones with Alkyl Acetates.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Cleavage or Acetyl-de-alkylation of 4-Methoxybenzyl (MPM) Ethers Using Acetic Acid

Abstract Aryl (4-methoxyphenyl)methyl (MPM) ethers are cleaved by heating with acetic acid for a few hours at 90°C, producing the corresponding phenols and (4-methoxyphenyl)methyl acetate. Under the same conditions alkyl MPM ethers are transformed directly into the corresponding alkyl acetates.

Pyrolysis of Alkyl Acetates. A Radical Pathway for the Formation of Minor Products

Decyl acetate and decene pyrolysis under the same reaction conditions show that the formation of the minor products during the pyrolysis of esters occurs by a parallel, and not a secondary, reaction. The radioactivity observed in the CO 2 and CO produced during the pyrolysis of 1-hexyl acetate-1- 14 C and the radioactivity in the methane from the pyrolysis of 1-hexyl acetate-2- 14 C strongly suggested a radical reaction pathway for the formation of the minor products. Considering the above results together with the radioactivity data of gas samples from the pyrolysis of 1-decyl-1- 14 C acetate, 1-hexyl-1- 14 C acetate, and 1-heptadecyl-1- 14 C acetate leads to the conclusion that the mechanism of pyrolysis of esters may be viewed as a cyclo-D E D N A N mechanism for the formation of the major alkene product and a radical mechanism for the formation of minor products

Selective Enzymatic Hydrolysis of Phenolic Acetates

Phenolic acetates are selectively hydrolyzed in the presence of alkyl acetates, methyl esters and cinnamates with pig liver acetone powder (PLAP).

Octadecanol Monolayers: The Phase Diagram

The phase diagram for octadecanol monolayers has been constructed from surface pressure-area isotherms determined for the temperature range 1-35°C. The diagram has been interpreted by comparison with monolayers of related amphiphiles using Peterson's principle of equivalent states (Peterson, I. R., in Polymers for Advanced Technology, in press; Peterson et al., Langmuir 8, 2995 (1992)). The resultant phase diagram is similar to those for long-chain acids, alkyl esters, and alkyl acetates, and it is probable that this is also the case for long-chain alcohols in general.

Measurement of equilibrium constants for the formation of esters from aliphatic carboxylic acids and alcohols

A method for assessing the magnitude of esterification equilibrium constants for a series of alkyl acetates is described. The constants are quite sensitive to electronic effects, with the largest values being obtained for those in which the alkyl groups are electron donating

Intramolecular nucleophilic acyl substitution reactions of halo-substituted esters and lactones. New applications of organosamarium reagents

Intramolecular nucleophilic acyl substitution reactions involving a broad range of halo substituted carboxylic acid derivatives have been accomplished in excellent yield employing samarium(II) iodide as the reductive coupling agent. Although particular substrates cyclized most effectively in THF in the presence of tripiperidinophosphine oxide, carboxylic acid esters, the focus of this report, cyclize equally well without such an additive in the presence of a catalytic quantity of iron(III) complexes. Thus a comprehensive series of halo substituted esters were cyclized in excellent yield to the corresponding 4-, 5-, and 6-members carbocycles. The reaction is extremely mild and selective as demonstrated by experiments wherein alkyl chlorides, acetals, and olefins remain completely intact under the reaction conditions. In addition to introducing a convenient procedure for preparing stereodefined spirocyclic systems, a new ring expansion sequence has been developed that appears extremely general for the preparation of various ring systems

Toxicity of homologous series of organic solvents for the gram‐positive bacteria Arthrobacter and Nocardia Sp. and the gram‐negative bacteria Acinetobacter and Pseudomonas Sp.

The toxicity of homologous series of organic solvents has been investigated for the gram-positive bacteria, Arthrobacter sp. and Nocardia sp., and the gram-negative bacteria, Acinetobacter sp. and Pseudomonas sp. The hydrophobicity of the solvent, expressed by its logP(octanol), proves to be a good measure for the toxicity of solvents in a two-phase system. The transition from toxic to nontoxic solvents occurs between logP(octanol) 3 and 5 and depends on the homologous series. No correlation has been found between the hydrophobicity of the substituent on the alkyl backbone of the solvent and the location of the transition point in toxicity. The logP(octanol), above which all solvents are nontoxic, is used to express the solvent tolerance of the bacteria. In general, the solvent tolerance of gram-negative bacteria is found to be slightly higher than that of gram-positive bacteria, but this does not hold for all homologous series of organic solvents investigated.Because the toxicity effects of organic solvents in a two-phase system can be ascribed to molecular as well as phase toxicity effects, molecular toxicity effects were investigated separately in a one-phase system with subsaturating amounts of organic solvent. The solvent concentration in the aqueous phase, at which 50% of the metabolic activity of the bacteria is lost, is used to express solvent toxicity. This concentration is found to be similar for the gram-positive Arthrobacter and the gram-negative Acinetobacter. Assuming the critical membrane concentration theory (G. J. Osborne et al. Enzyme Microb. Technol. 1990, 12: 281-291) to be valid, it can be concluded that differences in solvent tolerance between these two bacteria, cannot be ascribed to differences in response to molecular toxicity. Prediction of the toxicity of any solvent, using the critical membrane theory, appears to be possible in the case of alkanols or alkyl acetates. However, prediction of the toxicity of ethers appears to be impossible.

Synthesis, characterization, and carbonylation reactions of methylpalladium amide, carbamate, and alkyl carbonate complexes

A series of trans- and cis-methylpalladium carbamate complexes PdMe(OCONRR′)L 2 (L = tertiary phosphine; R, R′= H, alkyl, and phenyl) was prepared by the reaction of dimethylpalladium complexes with primary or secondary amine and carbon dioxide. When diphenylamine was used, methylpalladium amide complexes trans-PdMe(NPh 2)L 2 (L = PMe 3 and PEt 2Ph) were isolated instead of carbamates. The carbamate and amide complexes thus prepared were characterized by IR and NMR spectroscopy and elemental analysis. The carbamate complex trans-PdMe(OCONEt 2)(PMe 3) 2 released one of the PMe 3 ligands on recrystallization to form a dimeric compound Pd 2Me 2 (μ-OCONEt 2) 2(PMe 3) 2, whose structure was determined by X-ray diffraction study. The carbamate complexes reacted with carbon monoxide under pressure to give corresponding α-keto amide (MeCOCONRR′) and amide (MeCONRR′). Reactions of dimethylpalladium complexes with alcohols and carbon dioxide gave methylpalladium alkyl carbonate complexes trans-PdMe(OCOOR)L 2 (R = Me, sBu; L = PMe 3, PPh 3). Treatment of alkyl carbonate complexes with carbon monoxide afforded the corresponding alkyl acetate as the sole carbonylation product.

Difluorophenylselenomethylation of ethers

Pummerer reaction of difluoromethyl phenyl selenoxide with acetic anhydride proceeds at refluxing temperature of CH 2Cl 2, generating difluorophenylselenomethyl carbocation equivalent which can be trapped with cyclic ethers to give ω-(difluorophenylselenomethoxy)alkyl acetates 3.