Aqueous microwave-assisted one-pot synthesis of N-substituted rhodanines

Two aqueous, one-pot, microwave-assisted methods for the rapid synthesis of N-substituted rhodanines from amine substrates are described. Alkyl- and benzylamines could be converted into the corresponding rhodanines with an atom-efficient one-pot, three-step protocol based on carbon disulfide and chloroacetic acid in short reaction times and good to excellent yields. An alternative, microwave-assisted one-pot, one-step protocol using bis(carboxymethyl)trithiocarbonate in water was developed for the synthesis of N-arylrhodanines from anilines.     

An efficient one-flask synthesis of N-confused tetraphenylporphyrin

[formula: see text] N-Confused meso-substituted porphyrin is a porphyrin isomer previously available from one-flask porphyrin syntheses as a low-yield byproduct (< 7.5%). We have found that methanesulfonic acid catalyzed condensation of pyrrole and benzaldehyde followed by DDQ oxidation provides N-confused tetraphenylporphyrin (NC-TPP) in up to 39% yield in analytical scale experiments. Preparative synthesis provided an isolated yield of 35% (800 mg). This represents a > 5-fold yield improvement and makes significant quantities of NC-TPP readily available.     

Synthesis and transformations of (imidazolylimino)thiazolidinones

The reaction of ethyl 5-phenylthioureido-3H-imidazole-4-carboxylate with bromoacetic acid afforded (imidazolylimino)thiazolidinones, which were transformed into the corresponding 5-arylidene-4-thiazolidinones by the reactions with aldehydes. Under the conditions of the Knoevenagel reaction, the thiazolidine ring in derivatives of 4-(4-oxothiazolidin-2-ylideneamino)-3H-imidazole-4-carboxamides was opened to form substituted guanidines.     

Three-component synthesis of alpha,beta-cyclopropyl-gamma-amino acids

[reaction: see text] The multicomponent coupling of alkenylzirconocenes with N-diphenylphosphinoyl imines provides rapid access to functionalized C-cyclopropylalkylamides which have been readily transformed into alpha,beta-cyclopropyl-gamma-amino acids. These novel scaffolds are thus accessible in ca. 8 steps from commercially available alkynes.     

Three-component, one-pot sequential synthesis of glyco-hydantoin conjugates

The development of new methods for linking sugars to heterocycles and peptides is an attractive area of research because glyco-conjugates play important roles in biology and medicine and are indispensable tools for probing several processes. Herein we report a one-pot, three-component sequential procedure for the synthesis of a novel class of glyco-conjugates, i.e. glyco-hydantoin conjugates, in high yields and very mild conditions, using readily accessible starting materials. We also demonstrated that some of the glyco-hydantoin conjugates obtained are synthons for the preparation of a novel class of glyco-pseudopeptides in which the amino acid is tethered to the sugar through the hydantoin ring.     

The synthesis of rhodanines with possible antimetabolic activity

Eighteen new derivatives of rhodanine were obtained by the reaction of 3--carboxyethylrhodanine with various oxo-compounds. The condensation proceeded fairly readily in glacial acetic acid with enanthaldehyde, acetal, diacetyl, pyruvic acid, furfural, anthraquinone, -chloroanthraquinone, isatin, 5-bromoisatin, acenaphthenequinone, isobutyraldehyde, cyclopentanone, and cyclohexanone. The condensations with acetone, ethyl methyl ketone, acetoacetic ester, acetophenone, and 2-acetylnaphthalene were carried out by heating in ammoniacal solution.For part II see [1].     

Three-component synthesis of amidoalkyl naphthols catalyzed by bismuth(III) nitrate pentahydrate

Bismuth(Ⅲ) nitrate pentahydrate catalyzed the three-component condensation ofβ-naphthol,aldehydes and amines/urea under solvent-free conditions to afford the corresponding amidoalkyl naphthols in excellent yields.     

Three-component, stereoselective palladium-catalyzed synthesis of functionalized bicyclopentanoids

1,5-Cyclooctadiene can be stereoselectively transformed into a substituted bicyclo[3.3.0]octane ring system under palladium catalysis with concomitant formation of three carbon-carbon bonds. Reaction with an aryl iodide or triflate and malonate gives an exo-endo product, while the reaction with a malonate in the presence of oxygen affords a bis-endo adduct.     

Three-component, one-pot sequential synthesis of N-aryl, N'-alkyl barbiturates

[reaction: see text] Condensation between N-alkyl, N'-aryl carbodiimides and malonic acid monoesters leads to a high-yield formation of N-acyl urea derivatives that could be cyclized to C-monosubstituted barbiturates by addition of a suitable base in a one-pot sequential fashion. In the presence of an electrophile, the last step gives rise to a one-pot, three-component sequential synthesis of fully substituted barbiturates.     

La(OTf)3-catalyzed one-pot synthesis of meso-substituted porphyrinic thiazolidinones

Abstract  

An improved synthetic procedure is developed for the regioselective nitration of a phenyl group of meso-tetraphenylporphyrin by using NaNO₂ in a mixture of trichloroacetic acid and AcOH. The meso-(4-nitrophenyl)porphyrins are successfully reduced to corresponding meso-(4-aminophenyl)porphyrins by SnCl₂ under acidic conditions. In addition, an efficient one-pot methodology for synthesizing a series of novel meso-substituted porphyrinic thiazolidinone conjugates is developed by reacting meso-(4-aminophenyl)porphyrins with various aromatic aldehydes and mercaptoacetic acid in refluxing toluene using La(OTf)₃ as a catalyst. The products obtained are characterized on the basis of their spectral data. Preliminary photophysical properties of the newly synthesized compounds are reported.     

Three-component diastereoselective cascade synthesis of thiohydantoins

A new three-component cascade reaction for the synthesis of thiohydantoins is reported. The reaction between α-amino esters, nitrostyrenes, and aromatic isothiocyanates is efficiently promoted by organic bases to afford highly substituted thiohydantoins in moderate to good yields and diastereoselectivities.     

Three-component synthesis of 3,4-dihydroisoquinoline derivatives

A simple and convenient method for the synthesis of 1-substituted 3,3-dimethyl-3,4-dihydroisoquinolines was developed. The method is based on the [2+2+2] cyclization of alkyl- or alkoxybenzenes with isobutyraldehyde and nitriles.     

Three-component synthesis of 2-halo-6-methoxy-5,6-dihydropyridine-3,4,4(1H)-tricarbonitriles

Russian Journal of Organic Chemistry - One-stage preparation method of 2-halo-6-methoxy-5,6-dihydropyridine-3,4,4(1H)-tricarbonitriles was developed, consisting in the reaction of...     

Three-component synthesis of polysubstituted homoproline analogs

Tetrasubstituted pyrrolidines representing analogs of homoproline were synthesized by three-component condensation of aryl(heteroaryl)aldehydes, asparagine and N-methylmaleimide (NMM). Compounds with (1S*, 3R*, 3aS*, 6aR*)-configuration at the corresponding carbon positions of the bicyclic pyrrolidine ring could be isolated ona preparative scale.     

Three-component synthesis of 2-imino-1,4-benzoxazines

A series of 2-imino-1,4-benzoxazines (8a-e) were prepared by the one-pot, three-component, condensation of salicylaldehyde (4), various ortho-aminophenols (5), and 2,6-dimethylphenylisonitrile (6). The structures of four of the crystalline benzoxazine derivatives (8b-e) were unambiguously established by X-ray analysis.     

Three-component synthesis of hexahydropyridopyrimidine-spirocyclohexanetriones induced by microwave

Pyridopyrimidine-spirocyclohexanetriones (5, 6) and pyrimido[4,5-b]quinolinones (8) were obtained in a three-component microwave-assisted reaction of 6-aminopyrimidin-4-ones (1) with dimedone (2) and formaldehyde solution or paraformaldehyde, respectively. A mechanism is proposed based on the presence of a basic catalyst (triethylamine in this case) and the fact that single condensation intermediates are isolated prior to the cyclization leading to the final products.     

One-pot synthesis of novel fused pentacyclic chromenopyrimidobenzimidazolones and benzimidazolyl-chromenyl-substituted thiazolidinones

The ultrasound promoted synthesis of a number of novel fused pentacyclic chromenopyrimido[1,2-α]benzimidazolones by the one-pot reaction of 3-formylchromones with 2-aminobenzimidazole is described. Moreover, the isolated pentacyclic chromone derivatives upon microwave irradiation with 2-mercaptocarboxylic acids afforded benzimidazolyl-chromenylthiazolidinones incorporating three pharmacophoric heterocycles; the same thiazolidinones were also formed through a multicomponent reaction under microwave irradiation involving 3-formylchromones, aminobenzimidazole and 2-mercaptocarboxylic acids. The structural elucidation of the products was accomplished by 1D and 2D NMR experiments and for thiazolidinones was also confirmed by X-ray crystallographic analysis. Full assignment of all ¹H and ¹³C NMR chemical shifts has been unambiguously achieved. The proposed reaction mechanism is also discussed.     

以聚(4-乙烯基吡啶)硫酸氢盐为催化剂三组分一锅法合成苯并[f]茚并喹啉(英文)

7‐Aryl‐8H‐benzo[f]indeno[2,1‐b]quinoline‐8‐one derivatives were synthesized by means of a one‐pot condensation of 2‐naphthylamine, aromatic aldehydes, and indane‐1,3‐dione in ethanol under refluxing conditions in the presence of poly(4‐vinylpyridinium) hydrogen sulfate, a solid acid catalyst. This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The catalyst could be recycled and reused four times without significant loss of activity. The structure of the novel compounds was confirmed by IR, 1H NMR, and 13C NMR spec-troscopy and elemental analysis.     

An ionic liquid mediated one-pot synthesis of substituted thiazolidinones and benzimidazoles

An expeditious one-pot synthesis of 2,3-diaryl/2-aryl-3-heteroaryl-1,3-thiazolidin-4-ones and 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles have been accomplished by condensing hetero/aromatic amine, 2-mercaptoacetic acid, aromatic aldehyde and 1,2-phenylenediamine, 2-mercaptoacetic acid and aromatic aldehyde, respectively, in ionic liquids, viz, 1-butyl-3-methyl-imidazolium tetrafluoroborate and 1-methoxyethyl-3-methylimidazolium trifluoroacetate.     

Three-component synthesis of 2-chloropyridine-3,4-dicarbonitriles

Russian Journal of Organic Chemistry -