Hetaryl Aldehydes Research Articles

Unusual behavior of 2,2'-(Quinolin-8-ylmethylene)bis(1H-indene-1,3(2H)-dione): Gear-like rotation, merry-go-round tautomerization, reversible fragmentation and intramolecular cyclization

1,3-Indandione reacts with 8-quinolinecarbaldehyde to give, depending on the conditions, 2,2'-(quinolin-8-ylmethylene)bis(1H-indene-1,3(2H)-dione) 3 or 2-(quinolin-8-ylmethylene)-1H-indene-1,3(2H)-dione 4. The 2:1 adduct 3 exhibits dynamic behavior distinct from that of the 2-pyridyl analogue. On cooling, the singlets of the central CH and 2-CH protons resolve into a triplet and doublet, respectively. On heating, all aromatic protons of the two indandione moieties in 3 are averaged due to reversible gear-like rotation of the quinoline fragment driven by the keto-enol tautomerization. In strongly basic DMSO, adduct 3 is reversibly fragmented into 1,3-indandione and 1:1 adduct 4, the first example of 1:1 adduct of indanones with electron-deficient hetaryl aldehydes. Protonation with trifluoroacetic acid at low temperature reveals the presence of several protonated forms differing by the configuration of the central carbon. Theoretical DFT calculations of adduct 3, its tautomers, rotamers, transition states and protonated forms were performed to support the experimental results.

Unusual spontaneous oxidation of 2,2′‐(quinolin‐2‐ylmethylene)bis(1H‐indene‐1,3(2H)‐dione): An experimental and theoretical study of the mechanism

Abstract2‐Quinolinecarbaldehyde reacts with 1,3‐indandione to give 2‐[(3‐hydroxy‐1‐oxo‐1H‐inden‐2‐yl)(quinolin‐2‐yl)methylene]‐1H‐indene‐1,3(2H)‐dione, which is the first example of self‐oxidation of the Michael adducts of cycloalkanones with aldehydes. The structure of the product of oxidation is also proved by NMR and elemental analysis of its bromination product 2‐[(2‐bromo‐1,3‐dioxo‐2,3‐dihydro‐1H‐inden‐2‐yl)(1,3‐dioxo‐1,3‐dihydro‐2H‐inden‐2‐ylidene)‐methyl]quinolinium tribromide salt. The mechanism of this unusual reaction is studied experimentally and theoretically in comparison with that of a similar reaction with 2‐pyridinecarbaldehyde, which does not lead to self‐oxidation. The three‐step mechanism includes the formation of a pre‐reaction complex, which suffers proton transfer to the pyridinic nitrogen atom, and the hydride ion transfer to the protonated aldehyde. The transition states for the two reactions differ by the position on the reaction coordinate and the heights of the free energy barriers (~25 and ~4 kcal/mol), which allows to explain the observed different reactivity of the two similar hetaryl aldehydes.

Cell cycle arrest and induction of apoptosis of newly synthesized pyranoquinoline derivatives under microwave irradiation

A set of 2-amino-4-aryl-4H-pyrano[3,2-h]quinoline-3-carbonitrile derivatives were prepared via a one-pot, three-component condensation reaction between the substituted hydroxyquinoline derivatives, some aryl and/or hetaryl aldehydes, and malononitrile in an ethanol/piperidine solution in a microwave irradiation environment. The structure of the prepared compounds was instituted on the foundations of their spectral data: IR, 1H NMR, 13C NMR, and MS. Four human cancer cell lines, MCF-7, HCT-116, HepG-2, and A549 were utilized to evaluate the antiproliferative properties of the target compounds in comparison to the positive controls, Vinblastine and Colchicine using the MTT viability assay. The cell cycle arrest behavior, detected by propidium iodide as well as the apoptosis induction, which was monitored by the flow cytometer, using the Annexin V-FITC kits, was investigated. The results illustrated that the potent cytotoxic compounds induce cell cycle arrest at the G2/M phases and trigger apoptosis in the different tested cancer cells. Finally, the structure−activity relationship (SAR) study showcases the substitution of some specific groups at the 4-, 6-, and 9-positions in the prepared 2-amino-4H-pyrano[3,2-h]quinoline derivatives, which indicates that the lipophilicity manipulates the ability of these moieties against the diverse cell lines.

ChemInform Abstract: Easy Access to a Library of Alkylindoles: Reductive Alkylation of Indoles with Carbonyl Compounds and Hydrosilanes under Indium Catalysis.

AbstractVarious functionalized indoles are alkylated with a diverse range of alkyl, aryl or hetaryl aldehydes or ketones following a practical and scalable one or two step procedure.

ChemInform Abstract: N‐Heterocyclic‐Carbene‐Catalyzed Regioselective Oxidative Ring‐Opening of Epoxides with Aromatic Aldehydes: A Facile Entry to α‐Acyloxyketones.

Abstract2‐Substituted as well as 2,3‐disubstituted epoxides containing aryl, hetaryl, or alkyl groups are transformed with aryl or hetaryl aldehydes according to the title reaction.

ChemInform Abstract: An SiO2/ZnBr2 Mediated Expeditious Approach to 3‐Methyl‐1‐phenyl‐1H‐pyrazol‐5(4H)‐one Derivatives in Water under Microwave Irradiation.

AbstractThe one‐pot three‐component title reaction between ethylacetoacetate, phenyl‐ or 2,4‐dinitrophenylhydrazine and various aryl or hetaryl aldehydes proves more practical, efficient and eco‐friendly than previously developed methods.

ChemInform Abstract: Enantioselective Synthesis of Functionalized Polycarbocycles via a Three‐Component Organocascade Quadruple Reaction.

AbstractConditions for the scalable reaction of 1,3‐indanedione, 4‐substituted cyclohexanones and aryl or hetaryl aldehydes to form spirocyclic scaffolds with four stereogenic centers are elaborated.

ChemInform Abstract: (Chloromethyl)magnesium Chloride—Lithium Chloride: A Chemoselective Reagent for the Synthesis of Functionalized Aromatic Chlorohydrins.

AbstractAryl and hetaryl aldehydes are efficiently transformed to the corresponding chlorohydrins.

ChemInform Abstract: MgCl2·6H2O Catalyzed Highly Efficient Synthesis of 2‐Substituted‐1H‐benzimidazoles.

AbstractA new facile protocol is reported for the condensation of 1,2‐phenylenediamine with aryl‐ and hetaryl aldehydes to produce benzimidazoles.

ChemInform Abstract: Organocatalyzed Michael Addition on Arylmethylidenemalonates Involving 4‐(2‐Nitrophenyl)acetoacetate: Diversity‐Oriented Access to 8,9‐Dihydropyrido[1,2‐a]indol‐6(7H)‐one and Salicylate Scaffolds.

AbstractConditions for the one‐pot synthesis of hexa‐substituted salicylate derivatives are elaborated starting from 4‐(2‐nitrophenyl)acetoacetate and various aryl or hetaryl aldehydes.

ChemInform Abstract: A Facile One‐Pot Synthesis of 2‐(2‐Pyridyl)quinolines via Povarov Reaction.

AbstractThe title reaction starts from anilines, hetaryl aldehydes, and ethyl vinyl ether and is incompatible with sterically hindered or halogen‐containing anilines.

ChemInform Abstract: A Phosphine‐Catalyzed Regioselective [3 + 2] Cycloaddition of Ethyl 5,5‐Diarylpenta‐2,3,4‐trienoate with Aromatic Aldehydes and α,β‐Unsaturated Carbonyl Compounds.

AbstractA series of methylidene substituted 2,5‐dihydrofurans is prepared via the reaction of ethyl 5,5‐diphenylpenta‐2,3,4‐trienoate (I) with aryl or hetaryl aldehydes.

Catalytic asymmetric intermolecular Stetter reactions of enolizable aldehydes with nitrostyrenes: computational study provides insight into the success of the catalyst.

Over the past decade, N-heterocyclic carbenes (NHCs) have been used as catalysts in a variety of C-C bond forming reactions.[1] Our group has been interested in the development of chiral NHCs as catalysts for the asymmetric intra-molecular Stetter reaction[2,3] and more recently the inter-molecular variant.[4,5] We recently reported that hetaryl aldehydes and enals react efficiently with nitroalkenes in the Stetter reaction, leading to β-nitro ketones with high enantioselectivity.[4d] Crucial to the success of this method was the development of a fluorinated triazolium salt pre-catalyst that provides significantly enhanced enantioselectivity over des-fluoro analogues.[6] Although this new catalyst system greatly expands the scope of this method, these conditions are not amenable to the use of unactivated aliphatic aldehydes. Due to their lower electrophilicity than aryl aldehydes, aliphatic aldehydes have rarely been used successfully in the asymmetric inter-molecular Stetter reaction.[7,8]

An efficient preparation of new homoallylamines and α‐aminonitriles bearing furyl and thienyl rings

Abstractmagnified imageNew diverse N‐aryl‐N‐[1‐furyl(thienyl)but‐3‐enyl]amines (homoallylamines) or 2‐(N‐arylmethylamino)‐2‐furyl(thienyl)acetonitriles (α‐aminonitriles) were easily prepared in good to excellent yields by an indium‐mediated Barbier‐type reaction between N‐hetarylaldimines and allyl bromide in MeOH or a direct three component reaction between anilines, hetaryl aldehydes and trimethylsilyl cyanide in the presence of a catalytic amount of molecular iodine at room temperature, respectively. The entire set of amines was characterized by IR, 1H and 13C NMR spectroscopy.

Synthesis of Diarylketones from Arylboronic Acids and Aldehydes

The benzophenone unit is encountered in various biologically relevant molecules. This reaction offers a simple and versatile process for the preparation of functionalized benzophenones, starting from aryl or hetaryl aldehydes and arylboronic acids. It avoids the regioselectivity and functional group compatibility problems, associated with the conventional Friedel-Crafts reaction or the application of highly reactive organometallic species.

Novel substituted 2‐acetamido thiophene‐4‐styryl disperse dyes

AbstractEthyl 2‐acetamido‐3‐cyano‐5‐carbethoxy thiophene‐4‐acetic acid ester has been synthesised by the Gewald reaction of diethyl acetonedicarboxylate, sulphur and malononitrile, followed by acetylation. A variety of aryl and hetaryl aldehydes were condensed with this thiophene derivative in refluxing DMF in the presence of piperidine to yield novel styryl dyes. The fluorescence in solution and dyeing properties of these styryl dyes on polyester were studied.

Mechanism of the catalytic oxidation of nitrogen-containing methyl-substituted heterocycles to hetaryl aldehydes

An interrelationship between the electronic structures of methyl derivatives of nitrogen-containing heterocyclic compounds and the character of the interaction with the catalyst, the mechanism of heterogeneous-catalytic oxidation, and the selectivity of the process was established.