Ethoxycarbonyl Substituents Research Articles

Monomolecular sheets of propeller-shaped triethyl 4,4',4''-[benzene-1,3,5-triyltris(ethyne-2,1-diyl)]tribenzoate deuterochloroform monosolvate.

The title compound, C39H30O6·CDCl3, has a chemical threefold axis and an approximately planar structure, with an ethoxycarbonyl substituent on each of the terminal benzenes oriented in the same direction, thus forming a propeller-shaped molecule. This molecule is of particular interest in the field of metal-organic frameworks (MOFs), where its hydrolyzed analogue forms MOF structures with high surface areas. The benzene ring which occupies the centre of the molecule forms π-π interactions to the equivalent benzene ring at a perpendicular distance of 3.32 (1) Å. Centrosymmetric dimers formed in this way are interconnected by intermolecular C-H···π interactions with a rather short H···CgA distance of 2.51 Å (CgA is the centroid of the central benzene ring). The molecules are arranged in regular parallel sheets. Within a sheet, molecules are interconnected via C-H···O interactions where all carbonyl O atoms participate in weak hydrogen bonds as hydrogen-bond acceptors. Neighbouring sheets are connected through the above-mentioned π-π and C-H···π interactions.

Synthesis of Asymmetrically Substituted Terpyridines by Palladium‐Catalyzed Direct CH Arylation of Pyridine N‐Oxides

The synthesis of asymmetrically substituted 2,2':6',2''-terpyridines is reported. First, palladium-catalyzed C-H arylation of pyridine N-oxides with substituted bromopyridines gave 2,2'-bipyridine N-oxides, which were further arylated in a second step to form 2,2':6',2''-terpyridine N-oxides. Yields of up to 77% were obtained with N-oxides bearing an electron-withdrawing ethoxycarbonyl substituent in the 4-position. Pd(OAc)2 with either P(tBu)3 or P(o-tolyl)3 was used as the catalyst. Cyclometalated complexes derived from Pd(OAc)2 and these phosphines were also effective. K3PO4 as the base gave better results than K2CO3. Subsequent deoxygenation with H2 and Pd/C as the catalyst gave the asymmetrically substituted 2,2':6',2''-terpyridines in near quantitative yield. This reaction sequence significantly reduces the number of steps required in comparison with known cross-coupling methods and therefore allows convenient and scalable access to substituted terpyridines.

Cation-dependent binding of zinc diethoxycarbonylcalix[4]arenebis(porphyrinate) triethylenediamine

Zinc calix[4]arene-bis(porphyrinate) with two ethoxycarbonyl substituents at the lower rim of the calix[4]arene moiety was synthesized. Its complexation properties toward the sodium cation and triethylenediamine were studied. The influence of the binding of the sodium cation by the calix[4]arene moiety on the complexation properties of the interporphyrin cavity toward triethylenediamine was revealed.

Rearrangements of the [2+2]-cycloadducts of DDQ and 2-ethynylpyrroles

The [2+2]-cycloadducts of DDQ and 2-ethynylpyrroles, upon ethanolysis (reflux, 15 min or room temperature, 24 h), rearrange from bicyclo[4.2.0]octadienediones to bicyclo[3.2.0]heptadienone- and cyclobutenyl-dihydrofuranone moieties in 55–83% yields, the former rearrangement being the major direction. Benzoquinone ring cleavage is regioselective to afford mostly bicyclo[3.2.0]heptadienone-pyrrole ensembles (85–90% selectivity) in 39–78% yields. The only exception is when the starting compounds contain an ethoxycarbonyl substituent and the pyrrole counterpart is a 4,5,6,7-tetrahydroindole fragment. In this case, the ratio of the rearrangement products is 1:1.2 in a total yield of 83%. An important feature of the dihydrofuranone pathway rearrangement is its 100% diastereoselectivity.

Ethyl 1'-[1-(4-methoxyphenyl)-3-phenoxy-4-phenylazetidin-1-yl]-1,3-dioxo-2′,3′,5′,6′,7′,7a′-hexahydroindan-2-spiro-3′-1′H-pyrrolizine-2′-carboxylate

In the title compound, C34H32N2O7, the methyl group and methylene H atoms of the ethoxycarbonyl substituent are disordered over two positions with site occupancy factors for the major and minor conformers of 0.594 (8) and 0.406 (8), respectively. The unsubstituted ring of the pyrrolizine ring system exhibits a twist conformation, the other an envelope conformation. In the crystal structure, mol­ecules are linked through C—H⋯O hydrogen bonds; intramolecular C—H⋯O interactions are also observed.

Synthesis and in vitro cytotoxic evaluation of 1,3-bisubstituted and 1,3,9-trisubstituted β-carboline derivatives

A series of novel 1,3-bisubstituted and 1,3,9-trisubstituted β-carboline derivatives was synthesized from the starting material l-tryptophan. Cytotoxic activities of these compounds were investigated in vitro. The results showed that 1,3,9-trisubstituted β-carboline derivatives had higher cytotoxic activities in vitro than the corresponding 1,3-bisubstituted compounds. Among all the synthesized 1,3,9-trisubstituted β-carboline derivatives, the compounds with a methyl substituent at position-1 displayed more potent cytotoxic activities, furthermore compound 5e having an ethoxycarbonyl substituent at position-3 and a pentafluorobenzyl at position-9, respectively, was found to be the most potent compounds of this series with IC 50 value of 4 uM against BGC-823 cell lines. These data suggested that (1) the cytotoxic potencies of β-carboline derivatives were enhanced by the introduction of appropriate substituents into position-1 and position-9 in β-carboline; (2) the β-carboline structure might be an important basis for the design and synthesis of new antitumor drugs; (3) the methyl substituent at position-1, the pentafluorobenzyl group at position-9 and the ethoxycarbonyl substituent at position-3 were the optimal combination for the improvement of cytotoxic activity of the β-carboline derivatives.

DFT Calculations Indicate that 1,4‐Dihydropyridine Is a Promising Lead Antioxidant

AbstractBy density‐functional‐theory (DFT) calculations, 1,4‐dihydropyridine (1) was found to be a powerful lead antioxidant with high H‐atom‐donating ability and relatively low pro‐oxidant activity. Moreover, two ethoxycarbonyl (EtOCO) substituents at C(2) and C(6) should further enhance its H‐atom‐donating ability due to resonance effects.

The Effect of the Heteroatom Moiety of Allylic Salts on the Addition Fragmentation Initiation of Cationic Polymerization

Thermally and photoinduced cationic polymerizations of cyclohexene oxide (CHO) initiated by allylthiophenium, allylpyridinium, allylalkoxypyridinium and allylphosphonium salts with non-nucleophilic counter anion hexafluoroantimonate and with an ethoxy carbonyl substituent at the allylic moiety were studied. The catalytic activities in the polymerization were examined and compared to those measured in both the absence and presence of added radical initiators.

Ethyl 5-methyl-4-(2,5,5-trimethyl-1,3-dioxan-2-yl)isoxazole-3-carboxylate

The title compound, C(14)H(21)NO(5), possesses an isoxazolyl group in the axial position of the 1,3-dioxanyl ring. The two rings are rotated about the bond joining them such that the two C(methyl)-C(dioxanyl)-C-C torsion angles are 92.1 (2) and -84.1 (2) degrees. In this conformation, neither the methyl nor ethoxycarbonyl substituents on the isoxazole are presented towards the dioxanyl chair.

Haloacetylated enol ethers. 11. Synthesis of 1‐methyl‐ and 1‐phenyl pyrazole‐3(5)‐ethyl esters. A one‐pot procedure

AbstractA one‐pot synthesis of 1‐methyl‐ and 1‐phenylpyrazole‐3(5)‐ethyl esters 2,3a‐e by the cyclocondensation of β‐alkoxyvinyl trichloromethyl ketones 1a‐e with methyl and phenyl hydrazine hydrochloride under mild conditions, is reported. A study using compounds 1a‐e with different substituents proved that these are versatile building blocks for the synthesis of pyrazole derivatives, having a 3(5)‐ethoxycarbonyl substituent in good yields (60–89%). The hydrazine and β‐alkoxyvinyl trichloromethyl ketone substituent effects on the reaction regiochemistry on the formation of the 1,3‐ and 1,5‐isomer were observed.

Ditopic Calixcrowns with Inequivalent Crown Loops: Synthesis and Structural Characterisation of an Unsymmetrical Calix[4]arene biscrown-6

Consecutive base-catalysed reactions of calix[4]arene with the ditosylates of two different polyetherdiols result in the relatively efficient production of an unsymmetrical calix biscrown-6 which, after reduction of an ethoxycarbonyl substituent to an hydroxymethyl group, has been characterised structurally by a room-temperature, single crystal X-ray study of its chloroform solvate. Crystals of ( 4), C53H62O13... ∼0.57CHCl3, are triclinic, P¯1, a 18.95(3), b 12.394(9), c 11.756(7) A α 106.93(5), β 101.77(8), γ 94.63(8)°, Z = 2; R was 0.088 for 2231 ’observed' (I > 3σ(I)) diffractometer data.

Racemic Ethyl 4-(2-Fluorophenyl)-2,6,6-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate

The title compound, C21H24FNO3, has potential calcium modulatory properties. The 1,4-dihydropyridine ring has a shallow boat conformation with the 2-fluorophenyl substituent in an axial synperiplanar orientation. The quinoline ring has a half-chair conformation. Steric interactions between the adjacent methyl and ethoxycarbonyl substituents cause local bond-angle distortions. The molecules are linked into chains by intermolecular N—H⋯O hydrogen bonds.

?-hydroaxyalkyl(benzyl)furozans and ?-hydroxyalkyl(benzyl)furoxans synthesis and reactivity

A general and simple preparative method for the synthesis of α-hydroxyalky(benzyl)furazan and -furoxan derivatives is proposed, The method involves reduction of acyl or ethoxycarbonyl substituents in these heterocyclic compounds with NaBH4 in ethanol. Based on the alcohols thus prepared, a number of previously unknown functional derivatives (α-nitroxyalkyl-α-haloalkyl-, and α-azidoalkylfurazans and -furoxans) have been synthesized.

Preparation of New 1-Alkenylphosphonates and 2-Alkenylphosphonates by Claisen Rearrangement

Abstract The thermally induced Claisen rearrangement of various isomeric diethoxyphosphorylallyl vinyl ethers gives 1-alkenyl-phosphonates and 2-alkenylphosphonates with differently located ethoxycarbonyl and acyl substituents.

Structure of a Diels–Alder adduct at a 5,7-disubstituted thebaine derivative

The structure of (+)-ethyl 3,18-dimethoxy-5β,17-dimethyl-4,5α-epoxy-6β,14β-ethenomorphinan-8β-carboxylate (3), C 25 H 31 NO 5 , is described. Diels-Alder reaction of the thebaine analogoue (-)-5β-methyl-7-methoxy-6-demethoxythebaine (2), with ethyl propenoate gives rise to anomalous α-face approach of the dienophile, yielding the title compound (3), in which the etheno bridge is at the 6β,14β position and the ethoxycarbonyl substituent is at the 8β position

Mechanisms of dicarboximide ring opening in aqueous media: Procymidone, vinclozolin and chlozolinate

AbstractThe hydrolysis kinetics of the dicarboximide fungicides procymidone, vinclozolin and chlozolinate in neutral and alkaline solutions of pH 60 to 13·7 at 25°C have been determined conjointly by ultraviolet spectrophotometry and by high performance liquid chromatography. Under alkaline conditions, the fungicides undergo attack by the hydroxide ion on a specific carbonyl group and the rate of hydrolysis increases proportionally to the hydroxide ion concentration. Procymidone gives quantitatively and irreversibly 2‐(3,5‐dichlorophenylcarba‐moyl)‐l,2‐dimethylcyclopropanecarboxylate. The reaction is not subject to general base catalysis and experimental data are in agreement with a rate‐determining attack by the hydroxide ion. After a rapid hydrolytic loss of the ethoxycarbonyl substituent from chlozolinate, the dicarboximide ring cleavage of the two other fungicides leads, by mechanisms which differ with respect to the type of base catalysis and the rate‐determining step, to the corresponding anilides, producing as intermediates the carbamic acids, which undergo loss of carbon dioxide. The hydrolysis of vinclozolin and chlozolinate yields, respectively, N‐(3,5‐dichloro‐phenyt)‐2‐hydroxy‐2‐methylbut‐3‐enanilide and N‐(3,5‐dichlorophenyl)‐2‐hydroxy‐propanilide.

Substituenteneffekte auf die CC‐Bindungsstärke, 13. Kinetische und thermodynamische Stabilität von α1‐alkylierten α1‐Amino‐carbonsäureestern – Stabilisierungsenergie von α1‐Amino‐α1‐(ethoxycarbonyl)alkyl‐Radikalen

Substituent Effects on the Strength of CC Bonds, 13[1]. – Kinetic and Thermodynamic Stability of α1‐alkylated α1‐Amino Acid Esters – Energy of Stabilization of α1‐Amino‐α1‐(ethoxycarbonyl)alkyl RadicalsThermolytic cleavage of 1a–c and 2a–c into radicals in solution are clean first‐order processes. The activation parameters for CC bond homolysis were determined. Compared with the corresponding data for hydrocarbons of equal strain a decrease of bond strength of 14.4 kcal/mol results by the combined interaction of the amino and the ethoxycarbonyl substituents. The heat of formation of 5 was determined by combustion calorimetry [δHco (1)– 1207.75 ± 0.20 kcal/mol] combined with the heat of vaporization (δHvo13.31 ± 0.10 kcal/mol). Compared with the additive behaviour of group increments the resulting heat of formation (δHfo (g)– 112.02 ± 0.24 kcal/mol] suggests a synergetic, geminal destabilization of Hsyn1.9 ± 1.4 kcal/mol. Combination of the kinetic data of bond homolysis of 1a–c and 2a–c with the synergetic ground‐state destabilization leads to a synergetic, capto‐dative radical stabilization of Hsyn (rad)6.7 kcal/mol.

A novel and stereodefined synthesis of (E)-β-ethoxycarbonylvinylsilanes: regio- and stereo-controlled hydroethoxycarbonylation of silylacetylenes by palladium(II) catalysis

[PdCl2(dppf)]–SnCl2·2H2O catalysed hydroethoxycarbonylation of silylacetylenes 1 provided a novel and convenient synthesis of (E)-β-ethoxycarbonylvinylsilanes 2. The reactions, carried out under mild conditions (90 °C. 20 kg cm–2) gave the products 2 in excellent yields. This procedure tolerated the presence of chloro or ethoxycarbonyl substituents separated from the carbon-carbon triple bond in silylacetylene 1. α-Trimethylsilylmethylene-γ-butyrolactones 11, with an alkoxycarbonyl substituted vinylsilane moiety, were obtained in excellent yields by the reaction of tetrahydropyranyl ethers of 4-trimethylsilylbut-3-yn-1-ols 10. A reasonable mechanism for the regioand stereo-controlled hydroethoxycarbonylation is described.

Sym-triazine derivatives. 9. Reaction of sym-triazines containing trichloromethyl and ethoxycarbonyl groups with phenylhydrazine

Using the example of the reaction of 1,3,5-triazines simultaneously containing trichloromethyl and ethoxycarbonyl substituents with phenylhydrazine, it was shown that the presence of even one ester group leads to ring transformation. Depending on the number of the ester groups in the initial 1,3,5-triazine, the reaction products are either 1,2,4-triazole or 1,2,4-triazine derivatives.

The Synthesis of Some Pyrimidinyl and Thiazolyl Ureas and Thioureas and Some Related Compounds

Some pyrimidin-2- and pyrimidin-4-amines were treated with isocyanates and isothiocyanates to give the corresponding disubstituted ureas or thioureas . A pyrimidin-2-amine is more reactive than a pyrimidin-4- amine in these reactions. 2-Aminothiazoles and thiazolinones also react to give the disubstituted ureas or thioureas . The use of ethoxycarbonyl or benzoyl isothiocyanate or isocyanate gives products which are readily hydrolysed to the pyrimidinyl or thiazolyureas or thioureas but with concomitant hydrolysis and decarboxylation of an ethoxycarbonyl substituent . The use of chlorosulfonyl or trimethylsilyl isocyanate gives the urea derivative without isolation of the intermediate disubstituted urea. Some related compounds were also synthesized.