Ethyl Acetates Research Articles

Stereodivergent reduction of enelactams embedded in hexahydroindoles. Synthesis of trans-3-substituted- cis-3a-methyloctahydroindoles

A stereodivergent synthesis of cis- and trans-octahydroindole derivatives from the ethylene acetal of methyl 1-benzyl-3a-methyl-2,5-dioxo-2,3,3a,5,6-hexahydro-1 H-3-indoleacetate is reported. Under ionic reduction conditions the enamide group was reduced to afford a trans-ring fused product, while a hydrogenation process led to the formation of a cis-ring fused lactam, which was transformed into a building block for daphniphyllum alkaloid synthesis after an epimerization at C-3.

Olfactory properties of straight‐chain undecan‐x‐ones, undecan‐x‐ols (x = 2–6) and their derivatives

AbstractA series of undecan‐x‐ones (x = 2–6) was used as starting material in the synthesis of ethylene and propylene acetals, undecanols and their acetates. Undec‐3‐yl and undec‐6‐yl acetates, ethylene acetal of undecan‐3‐one and propylene acetals of undecan‐x‐ones (x = 2–5) have not yet been described. The odour properties for all the synthesized compounds have been determined. They have pleasant, fruity, herbaceous odours that can be described as food odours. The most valuable groups of compounds are ketones and their acetals, which have intense, pleasant, fruity, vegetable, spicy or herbaceous odours. In the case of alcohols, mild odours dominate with fruity, wooden or floral notes. All acetates have faint or mild fatty‐soapy odours. A correlation between the structure of the studied compounds and their odours has been found. Fruity odours appear among ketones and alcohols when a shift of the functional group from position 2 to the middle of the molecule occurs. In the studied ethylene and propylene acetals this shift strengthens their vegetable and spicy odours, respectively. Copyright © 2008 John Wiley & Sons, Ltd.

ChemInform Abstract: Chiral Bifunctional Organocatalysts in Asymmetric Aza‐Morita—Baylis—Hillman Reactions of Ethyl (Arylimino)acetates with Methyl Vinyl Ketone and Ethyl Vinyl Ketone.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.

Separation of Paraffin Wax Using Solvent Fractionation

In order to separate and characterize some grades of paraffin waxes from El-Ameria crude waxes (slack waxes), a one-stage fractional crystallization technique has been done to separate the paraffin waxes with different characteristics by using different solvents and solvent mixtures at ambient temperature of 20°C and fixed dilution and washing solvent ratios (S/F) of 4:1 and 2:1 by weight, respectively. The fractionating solvents used are n-hexane, methyl isobutyl ketone (MIBK), dioxane, ethyl acetate, and butyl acetate as a single solvent and a mixture of methyl ethyl ketone (MEK) containing benzene (B) and toluene (T) as a mixed solvent. The resulting data revealed that dioxane and n-hexane solvents are not suitable for fractional crystallization of slack waxes, and the most suitable solvents for separating paraffin waxes with the standard specifications are ethyl and butyl acetates, MIBK, and the mixture of MEK, B, and T (60:20:20 by weight, respectively).

Synthesis of N-substituted 1,2,3,4-tetrahydrobenz[ g]isoquinoline-5,10-diones

The synthesis of 1,2,3,4-tetrahydrobenz[ g]isoquinoline-5,10-dione hydrochlorides is reported starting from 1,4-dihydrobenz[ g]isoquinoline-3(2 H)-ones or ethyl (3-aminomethyl-1,4-dimethoxynaphth-2-yl)acetates. A third strategy relies on the synthesis of the title compounds via an N-protected 2-(3-bromomethyl-1,4-dimethoxynaphth-2-yl)ethylamine. The synthesized 1,2,3,4-tetrahydro-benz[ g]isoquinoline-5,10-diones are a new class of quinones, which have not been reported yet.

A convenient preparation of novel benzophenone derivatives

A simple and high yielding method for the synthesis of novel benzophenone derivatives has been developed starting from ethyl(4-aroylaroxy)acetates. Confirmation for the structures of the newly synthesized compounds was proved by their physical, analytical and spectral data (IR, 1H-NMR, 13C-NMR and MS).

Phosphine-catalyzed annulation of ethyl (arylimino)acetates: synthesis of highly functionalized oxoimidazolidines

This paper describes an unexpected and novel nucleophilic phosphine-catalyzed annulation of ethyl (arylimino)acetates to give polysubstituted oxoimidazolidine derivatives in moderate to good yields from simple and easily available starting materials under mild conditions. In this reaction, the addition of methyl vinyl ketone (MVK) is essential to induce the formation of oxoimidazolidines.

Nucleophilic addition to acetylenes in superbasic catalytic systems: XV. Vinylation of 2-hydroxymethylfuran

2-Hydroxymethylfuran reacted with acetylene in superbasic catalytic systems MOH-DMSO (M = Na, K) under mild temperature conditions (75–85°C, 1–2 h), yielding 80% of 2-vinyloxymethylfuran. The product, as well as acetaldehyde acetals derived therefrom, turned out to be promising as modifiers for electrolyte in lithium-sulfur rechargeable batteries.

Chiral Bifunctional Organocatalysts in Asymmetric Aza-Morita−Baylis−Hillman Reactions of Ethyl (Arylimino)acetates with Methyl Vinyl Ketone and Ethyl Vinyl Ketone

The bifunctional chiral phosphine Lewis base (R)-2'-diphenylphosphino-[1,1'-binaphthalene]-2-ol is an effective organocatalyst in the asymmetric aza-MBH reaction of ethyl (arylimino)acetates 1 with MVK and EVK to give the corresponding adducts in moderate to good yields and good to high enantiomeric excesses under mild conditions.

Ruthenium-Catalyzed Transformations of Cyclopropylethynes

The addition of various carboxylic acids to (trans-2-ethoxycyclopropyl)ethyne (1) by catalysis with [Ru(O2CH)(CO)2(PPh3)]2 proceeds regioselectively in the Mar­kovnikov sense with ring opening of the cyclopropyl group to furnish allenylacetaldehyde acyl ethyl acetals 3 in high yields (44-96%, 11 examples). The allenylacetaldehyde derivatives undergo palladium-catalyzed Heck-type cross coupling with iodobenzene and subsequent trapping of the π-allylpalladium intermediate with primary and secondary amines to yield labile [β-(1-aminomethyl)styryl]acetaldehyde acyl ethyl acetals 12 (24-83%, 4 examples). Anti-Markovnikov addition of carboxylic acids to the triple bond in (trans-2-ethoxycyclopropyl)ethyne (1) without ring opening can be brought about under [Ru(CH2CMeCH2)2(dppb)] catalysis to give 2-(trans-2-ethoxycyclopropyl)ethenyl esters 13 (69-92%, 3 examples). (1-Hydroxycyclopropyl)ethyn­e (14), under catalysis by [Ru(O2CH)(CO)2(PPh3)]2, reacts with carboxylic acids to yield 1-acetylcyclopropyl esters 15 (49-74%, 4 examples) by Markov­nikov-sense addition and intramolecular transesterification. Anti-Markovnikov- and Markovnikov-sense addition of carboxylic acids to unsubstituted cyclopropylethyne can both be achieved regioselectively under catalysis with [Ru(CH2CMeCH2)2(dppb)] and [Ru(O2CH)(CO)2(PPh3)]2 to furnish 2-cyclopropylethenyl esters 23 (68-98%, 6 examples) and 1-cyclopropylethenyl esters 24 (66-97%, 5 examples), respectively.

Lewis Acid Catalyzed Reaction of Arylvinylidenecyclopropanes with Ethyl (Arylimino)acetates: A Facile Synthetic Protocol for Pyrrolidine and 1,2,3,4‐Tetrahydroquinoline Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

β-oxoacids esters in the synthesis of benzo[f]quinoline derivatives

Condensation of ethyl acetoacetate and ethyl 3-oxo-3-(2-furyl-, 2-quinolyl-, 3-pyridyl)propanoates with azomethines of 2-naphthylamine series led to the formation of ethyl (3-arylbenzo[f]quinol-1-yl)acetates and of esters of the corresponding 3-aryl-1-heteryl-2-benzo[f]quinolylcarboxylic acids. The intermediate reaction products were isolated: ethyl 5-(2-naphthylamino)-3-oxo-5-phenylpentanoate, 2-[(aryl)(2-naphthylamino)methyl]-3-heteryl-3-oxopropanoates, dihydro and tetrahydro derivatives of benzoquinolylacetic and benzoquinolinecarboxylic acids.

Lewis Acid Catalyzed Reaction of Arylvinylidenecyclopropanes with Ethyl (Arylimino)acetates: A Facile Synthetic Protocol for Pyrrolidine and 1,2,3,4-Tetrahydroquinoline Derivatives

[reaction: see text] A number of pyrrolidine and 1,2,3,4-tetrahydroquinoline derivatives are prepared selectively in moderate to good yields by the reaction of arylvinylidenecyclopropanes 1 with ethyl (arylimino)acetates 2 in the presence of Lewis acid depending on the electronic nature both of 2 and R1 or R2 aromatic groups of 1.

Molecular and crystal structure of ethylene acetal of endo-endo-3-trityloxymethylbicyclo[3.3.1]nonane-2-on-7-ol

Molecular structure of ethylene acetal of 3-trityloxymethylbicyclo[3.3.1]nonane-2-on-7-ol (3) was determined by X-ray investigation. It was revealed that 3 has endo-endo-configuration and adopt chair-boat-conformation. The distortion of rings was evaluated by calculation of the Zefirov–Palyulin and Cremer–Pople puckering parameters. Failure of esterification of 3 was rationalized in terms of steric hindrance and intramolecular hydrogen bonding.

Spectroscopic characterization of 6‐hydroxy and 1‐methyl‐6‐hydroxybicyclo[2.2.2]octan‐2‐one ethylene acetals and ethylene dithioacetals

6-endo- and 6-exo-Hydroxybicyclo[2.2.2]octan-2-one and 1-methyl-6-endo- and 6-exo-hydroxybicyclo[2.2.2]octan-2-one ethylene acetals and ethylene dithioacetals 1-4 have been characterized by 1D and 2D NMR methods.

Thermal Activation of Molecular Tungsten Halide Clusters with the Retention of an Octahedral Metal Framework and the Catalytic Dehydration of Alcohols to Olefins as a Solid Acid Catalyst

When the molecular tungsten halide cluster (H3O)2[(W6Cl8)Cl6]·6H2O, with an octahedral metal framework, is heated to 50 and 150 °C in flowing helium gas, it changes into (H3O)2[(W6Cl8)Cl6] and [(W6Cl8)Cl4(H2O)2], respectively. Activation at 250 °C yields a poorly crystallized solid state cluster, [W6Cl8]Cl2Cl4/2, which exhibits catalytic activity for the dehydration of ethanol to yield ethylene and a small amount of ethyl ether and acetal. The activity is attributed to the Bronsted acidity of the hydroxo ligand that is produced by elimination of hydrogen chloride from the chloro and aqua ligands. The catalytic activity increases with increasing temperature, and reaches a maximum at 300 °C. The catalytic activity then disappears above 350 °C, at which temperature the crystallinity of the cluster improves and the active sites are included in the crystal. In the case of primary alcohols, the reactivity decreases with increasing length of the carbon chain, and secondary alcohols are more reactive than the corresponding primary alcohols. Halide clusters of niobium, molybdenum, and tantalum having the same metal framework are also active catalysts for these reactions.

An Efficient and Convenient Method for Synthesis of 1‐Substituted Imidazoles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Novel Method for the Synthesis of α‐Bromocinnamaldehydes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

(Triisopropylsilyl)acetaldehyde acetal as a novel protective group for 1,2-diols

(Triisopropylsilyl)acetaldehyde dimethyl acetal (TIPS-ADMA) was synthesized from chlorotriisopropylsilane in three steps. Cyclic and acyclic 1,2-diols can be transformed to (triisopropylsilyl)ethylidene acetals (TIPS-AA). Removal of the acetal by LiBF 4 regenerates the starting diol in excellent yield even in the presence of an acetonide of 1,2-diol. The TIPS-AA group can survive under the deprotection conditions of the acetonide in acetic acid at 80 °C. Selective protection of 2,3- and 4,6-diols for O-methyl d-mannoside with TIPS-ADMA and selective deprotection of the acetals have been achieved.

5-(Dimethoxymethyl)-2‘-Deoxyuridine: A Novel Gem Diether Nucleoside with Anti-Orthopoxvirus Activity

To provide potential new leads for the treatment of orthopoxvirus infections, the 5-position of the pyrimidine nucleosides have been modified with a gem diether moiety to yield the following new nucleosides: 5-(dimethoxymethyl)-2'-deoxyuridine (2b), 5-(diethoxymethyl)-2'-deoxyuridine (3b), 5-formyl-2'-deoxyuridine ethylene acetal (4b), and 5-formyl-2'-deoxyuridine propylene acetal (5b). These were evaluated in human foreskin fibroblast cells challenged with the vaccinia virus or cowpox virus. Of the four gem diether nucleosides, only the dimethyl gem diether congener showed significant antiviral activity against both viruses. This antiviral activity did not appear to be related to the decomposition to the 5-formyl-2'-deoxyuridine, which was itself devoid of anti-orthopoxvirus activity in these assays. Moreover, at the pH of the in vitro assays, 2b was very stable with a decomposition (to aldehyde) half-life of >15 d. The anti-orthopoxvirus activity of pyrimidine may be favored by the introduction of hydrophilic moieties to the 5-position side chain.