Acetylenic Esters Research Articles

Copper-Catalyzed Oxidative Cyclization of Maleimides with Amines and Alkyne Esters: Direct Access to Fully Substituted Dihydropyrroles and Pyrrole Derivatives.

An efficient and practical Cu(I)-catalyzed oxidative cyclization cascade reaction of diverse amines, alkyne esters and maleimides has been developed. The reactions can afford 4,6-dioxopyrrolo[3,4-b]pyrrole-2,3-dicarboxylates and related derivatives with satisfactory yields by altering the reaction conditions slightly. The substrate scope highlights the flexibility of the catalyst, and a reaction mechanism is also proposed.

A Synthesis of Functionalized 2-Indolizin-3-yl-1,3-benzothiazoles from 1-(1,3-Benzothiazol-2-ylmethyl)pyridinium Iodide and ­Acetylenic Esters

Functionalized 2-indolizin-3-yl-1,3-benzothiazoles were obtained in moderate yields from the reaction between 1-(1,3-benzothiazol-2-ylmethyl)pyridinium iodide and acetylenic esters in acetonitrile. When isoquinoline was used under similar conditions, dialkyl 3-(1,3-benzothiazol-2-yl)pyrrolo[2,1-a]isoquinoline-1,2-dicarboxylates were obtained. The structures of these products have been confirmed by ­X-ray diffractometry.

A new synthetic strategy towards 2,4,5-trisubstituted 1H-imidazoles and highly substituted pyrrolo[1,2-c]imidazoles by use of α-azidochalcones via Michael addition-cyclization followed by Wittig reaction

Efficient and facile protocols for the preparation of highly functionalized 1H-imidazoles and 5H-pyrrolo[1,2-c]imidazoles are described. Heating a mixture of an α-azidochalcones and N,N,N′,N′-tetramethyl guanidine under neat conditions gave the corresponding 2,4,5-trisubstituted 1H-imidazole via Michael addition-cyclization in excellent yields. Subsequently, the prepared 1H-imidazoles undergo addition-Wittig reaction with acetylenic esters in presence of triphenylphosphine in dichloromethane to afford 5H-pyrrolo[1,2-c]imidazoles in high yields.

A Synthesis of Functionalized Thiazoles and Pyrimidine-4(3H)-thiones from 1,1,3,3-Tetramethylguanidine, Acetylenic Esters, and Aryl Isothiocyanates

Aryl isothiocyanates react with dialkyl 2-{[bis(dimethylamino)methylene]amino}maleates, generated from 1,1,3,3-tetramethylguanidine and acetylenic esters, to afford 2-(dimethylamino)-1,3-thiazole derivatives, functionalized 2-(dimethylamino)-6-thioxo-1,6-dihydropyrimidines, and ethyl 2-(dimethylamino)-6-[(4-nitrophenyl)im­ino]-4-phenyl-6H-1,3-thiazine-5-carboxylate, in moderate to good yields.

Three-Component Reaction of Benzothiazole, Acetylenic Esters, Phenoles; Synthesis of Dialkyl 2-benzo[d]thiazol Derivatives Under Grinding.

Due to biological activity of a significant number of compounds containing benzothiazole ring system and in continuation of our interest in developing new environmentally benign methods for the synthesis of heterocyclic compounds by MCRs in this study we performed an efficient three-component from benzothiazole, acetylenic esters and hydroxyl aromatics compounds to synthesize of 2- benzothiazole derivatives in high yield. IR spectra were recorded using an FTIR apparatus. Melting points measured on an Electrothermal 9100 apparatus. Spectra were obtained in solution of CDCl3 using TMS as internal standard. Elemental analyses were carried out using a Heracus CHN-O- Rapid analyzer. A mixture of benzothiazole, dimethyl acetylenedicarboxylate and phenol were placed in a mortar. The mixture was ground with a mortar and pestle at room temperature for 12 min. After completion of the reaction, as indicated by TLC (ethyl acetate: n-hexane, 1: 3), the solvent was distilled off under reduced pressure and the residue was crystallized from diethyl ether. Treatment of benzothiazole and dialkyl acetylenedicarboxylates in presence of resorcinol and β-naphthol led to products 4 (dialkyl (E)-2-(2-(2-hydroxyphenyl)benzo[d]thiazol-3(2H)-yl-3- methylbut-2-enedioate), while we observed two isomer (Z) and (E) configurations (major and minor) in nearly 70:30 ratio when the reaction was repeated in presence of 8-hydroxy quinolone and DMAD. Also when we examined 2-nitro phenol, 4-nitrophenol, and 4-hydroxy quinoline, only one product 5 was obtained. This indicates that the reaction proceeds efficiently with electron-releasing substituted phenols. The reaction between benzothiazole and dialkyl acetylenedicarboxylates in the presence of some phenols without electron-withdraw substitution, presents a novel, one-pot, clean, convenient, simple and inexpensive approach into the synthesis of 2-benzothiazole derivatives of potential synthetic and pharmacologically interest. This procedure carries significant advantages because of the minimization of labor, time, and cost.

A one-pot synthesis of functionalized indenopyrrolizines from ninhydrin, α-amino acids, and acetylenic esters

An efficient synthesis of tetraalkyl 6a-hydroxy-3-alkyl-11-oxo-6a,11-dihydro-3H-indeno[1,2-g]pyrrolizine-1,2,5,6-tetracarboxylates via 1,3-dipolar cycloaddition reaction of azomethine ylides (generated in situ from α-amino acids and ninhydrin) with dialkyl acetylenedicarboxylates is described. The stereochemistry of these N-heterocycles has been confirmed by X-ray diffraction study.

Boranes in Organic Chemistry 1. α-Carbonylalkyl- and β-Oxyalkylboranes in Organic Synthesis

<p>This review is devoted to the synthesis of a-carbonylalkyl- and β-hydroxy-alkyl boranes and their use in organic synthesis. a-Carbonyl-alkylboranes include several heteroatomic compounds, in particular, [1.2.3]-diazaborinines, uracyl boronic acids, and [1.2.3.4]-diaza-diboretes. The latter type has been obtained by the ketene aminoborations. The reactions of halogenboranes with diazoesters and sulfur ylides resulting in formation of a-carbonyl alkylborates containing diazofunction or ylide structural fragment are described. Amino and halogen boration of acetylenic acid esters was also used for the synthesis of a-carbonyl alkyl boranes. Reactions involving Cr-carbene complexes and acetylenic borone esters were presented for the synthesis of naphthoquinone boronic acids. The formation of amidoboranes by boration of dichloroacetanilides was remined. Boration of 4,8-dimethoxy-2-quinolone with trimethylborates leading to 2-quinolone-3-boronic acid was described. The common synthetic method to a-carbonyl alkyl boranes based on the hydroboration of acrylic acid derivatives was discussed. The results of enhydrazones hydroboration, leading to stable cyclic complexes have been mentioned. The interaction of a-bromoketones with trialkyl or dialkylboranes represents as a general synthetic method to a-carbonyl alkyl boranes. Synthetic approaches to â-hydroxy alkyl boranes are performed. The wide spread hydroboration of vinyl and allyl esters received a well-described attention. The hydroboration of cyclanone enol acetates, 3-keto- and 17-keto-steroids and cyclic allyl alcohol acetates was discussed. The results of aliphatic and alicyclic vinyl esters (including dihydrofuran derivatives) boralylation leading to β-hydroxy alkyl boranes have been envisaged. The synthesis of optically active β-hydroxy alkyl boranes using chiral borane hydrides was discussed. The heterocyclic boran dihydrides are obtained by the hydroboration of dihydropyranes, chromenes and flavenes. Borosilylation of allyl allenylic esters was also been envisaged. The synthetic scheme to optically active boranes and further optically active alcohols were presented. The problems of selectivity regularities in hydroboration reaction by intermolecular complex formations have been discussed.</p>

A synthesis of functionalized arylthio-acrylates, benzo[b][1,4]thiazines and benzo[4,5]thiazolo[3,2-a]azepines from 2-methylbenzothiazole and acetylenic esters in aqueous media.

Alkyl(Z)-3-((2-(N-((E)-3-methoxy-3-oxoprop-1-en-1-yl)acetamido)phenyl)thio)acrylates are obtained from the reaction between 2-methylbenzothiazole and alkyl propiolates in 70% aqueous alcohol, in moderate yields. When dialkyl acetylenedicarboxylates were used under similar conditions, tetra-alkyl9,10-dihydrobenzo[4,5]thiazolo[3,2-a]azepine-7,8,9,10-tetracarboxylates, together with dialkyl4-acetyl-3,4-dihydro-2H-benzo[b][1,4]thiazine-2,3-dicarboxylates were obtained in about 4:1 ratios. The stereochemistry of these products has been confirmed by X-ray diffraction.

Unexpected simultaneous synthesis of trisubstituted quinolines and acylhydrazones under catalyst-free conditions

ABSTRACTTrisubstituted quinolines and acylhydrazones were unexpectedly prepared from a reaction of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides with acetylenic esters. Using of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides led to obtain not only quinoline, but also a second pharmaceutical important product acylhydrazone. Notably, excellent yields, operational simplicity, short reaction times, and the avoidance of the use of catalysts make this approach an attractive complementary method to produce quinoline-2,3-dicarboxylates. The crystal structure of 5a was determined using single-crystal X-ray crystallography. The results showed that crystal packing diagram of 5a is of two pairs of molecules that have two independent alternate intermolecular 1D-polymeric H-bonds between two perpendicular molecules.

A synthesis of fused acenaphthopyrrolizines via the 1,3-dipolar cycloaddition reaction of azomethine ylides with acetylenic esters.

An efficient synthesis of tetraalkyl 6a-hydroxy-3-alkyl-3H,6aH-acenaphtho[1,2-g] pyrrolizine-1,2,5,6-tetracarboxylates via the 1,3-dipolar cycloaddition reaction of azomethine ylides (generated in situ from [Formula: see text]-amino acids and acenaphthylene-1,2-dione) with dialkyl acetylenedicarboxylates is described. When glycine was used instead of alanine, phenylalanine, valine, or isoleucine, dialkyl (E)-1[Formula: see text]-(1,4-dialkoxy-1,4-dioxobut-2-en-2-yl)-2-oxo-[Formula: see text],5[Formula: see text]-dihydro-2H-spiro [acenaphthylene-1,2[Formula: see text]-pyrrole]-3[Formula: see text],4[Formula: see text]-dicarboxylates were obtained. The steric effects of the [Formula: see text]-amino acids side chains may be responsible for their different behaviors.

DABCO-catalyzed multi-component domino reactions for green and efficient synthesis of novel 3-oxo-3H-benzo[a]pyrano[2,3-c]phenazine-1-carboxylate and 3-(5-hydroxybenzo[a]phenazin-6-yl)acrylate derivatives in water

An efficient, convenient and environmentally benign procedure for the synthesis of novel 3-oxo-3H-benzo[a]pyrano[2,3-c]phenazine-1-carboxylate and 3-(5-hydroxybenzo[a]phenazin-6-yl)acrylate derivatives has been developed by domino three-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines and acetylenic esters in the presence of a catalytic amount of DABCO as an expedient, eco-friendly and reusable base catalyst in water. This green process produces biologically and pharmacologically significant heterocycles in a one-pot single operation and offers considerable advantages such as: operational simplicity, short reaction time, high yields, reusability of catalyst, absence of any tedious workup or purification and avoids hazardous reagents/solvents.

Carbene-catalyzed LUMO activation of alkyne esters for access to functional pyridines.

A carbene-catalyzed LUMO activation of α,β-unsaturated alkyne esters is reported. This catalytic process allows for effective reactions of alkyne esters with enamides to synthesize functional pyridines via simple protocols. A previously unexplored unsaturated alkyne acyl azolium intermediate is involved in the key step of the reaction.

Synthesis of novel thiazolidine-4-one derivatives and their anticancer activity

GRAPHICAL ABSTRACT

NaCN-catalized diastereoselective synthesis of meso-bisphosphonates from dialkyl(aryl) phosphites and acetylenic esters in aqueous acetone

GRAPHICAL ABSTRACT

One-pot synthesis of γ -spiroiminolactones and γ -dispiroiminolactones using N,N'-disubstituted parabanic acid and thioparabanic acid derivatives.

A direct entry and simple process for the synthesis of [Formula: see text]-spiroiminolactones present in a large number of natural products has been developed. In the first step, the synthesis of parabanic acid derivatives was commenced from the reaction of [Formula: see text]-disubstituted urea and thiourea with oxalyl chloride, then a three-component reaction was carried out with isocyanides, acetylenic esters, and [Formula: see text]-disubstituted parabanic acid derivatives. The method allows the construction of a variety of [Formula: see text]-spiroiminolactone structures in good to high yields starting from readily available precursors. It was found that in the case of [Formula: see text]-diphenyl thioparabanic acid, additional products of [Formula: see text]-dispiroiminolactones have been formed due to the higher electrophilicity of [Formula: see text]-dicarbonyl groups. The structures were fully established using spectroscopic analysis NMR, IR, and Mass spectrometry. The crystal structure of [Formula: see text]-dispiroiminolactone was confirmed from single-crystal X-ray diffraction study.

Regioselective Synthesis of 2,3,4-Trisubstituted Pyrroles via Pd(II)-Catalyzed Three-Component Cascade Reactions of Amines, Alkyne Esters, and Alkenes

A new, efficient, and versatile Pd(II)-catalyzed oxidative three-component cascade reaction of diverse amines, alkyne esters, and alkenes is disclosed for the direct synthesis of diverse 2,3,4-trisubstituted pyrroles with broad functional group tolerance and in good to excellent yields. This transformation is supposed to proceed through the cascade formation of C(sp2)-C(sp2) and C(sp2)-N bonds via Pd(II)-catalyzed regioselective alkene migratory insertion, intramolecular radical addition, and oxidation sequential processes.

Total Synthesis of Nuclear Factor of Activated T-Cells-68 (NFAT-68): Sequential Use of Chiral Allenylsilane and Titanium Alkoxide-Mediated Reductive Coupling Bond Construction.

Highly enantioenriched chiral allenylsilanes 4 were prepared in high yield through a scalable synthetic sequence, employing a modified copper-catalyzed SN2' reaction. These reagents were used for the production of enantioenriched homoproparglylic ethers 5, which were subjected to titanium alkoxide-mediated reductive coupling with acetylenic esters to produce (E,E)-dienes 6 bearing α,β,γ,δ-unsaturated esters. Both enantiomers of nuclear factor of activated T-cells-68 (NFAT-68) were synthesized in five steps with the sequential use of the two methods.

Synthesis, Structure, and Unusual Reactivity of a Stable 3-(Oxazolidin-2-ylidene)thiophen-2-one

Treatment of 2- and 3-thienyloxazolines with butyllithium and bis(trimethylsilyl) peroxide results in ring hydroxylation to give products that exist mainly as the oxazolidinylidenethiophenones. The 3-oxazolidinylidenethiophen-2-one is a rare example of a stable heterocyclic o-quinone methide analogue that shows a varied pattern of reactivity, including both C- and O-alkylation, Michael addition via C-5 to an acetylenic ester, tetrachlorobenzannulation across positions 4 and 5, and formation of a hexacyclic fused-ring product with N-phenyltriazolinedione. Crystal structures of the products are dominated by inter- and intramolecular NH to CO hydrogen bonding.

ChemInform Abstract: A One‐Pot Synthesis of Trichloromethylated Pyrimidines from Trichloroacetimidamides and Acetylenic Esters.

AbstractTrichloroacetimidamides generated in situ from guanidines and trichloroacetonitrile undergo an addition reaction with acetylenic esters to afford highly functionalized pyrimidine derivatives.

ChemInform Abstract: Synthesis of Dimethyl 2‐{1‐[(1‐Methylimidazol‐2‐yl)sulfanyl] ‐1H‐isoquinolin‐2‐yl}but‐2‐enedioate and Related Compounds.

AbstractThe title compounds are prepared under mild reaction conditions by simple one‐pot three‐component reaction of acetylenic esters, isoquinoline, and methylimidazolethiol or methyltetrazolethiol as S—H acids.