Zinc perchlorate catalyzed one-pot synthesis of 3,4-dihydropyrimidinones under solvent-free conditions

Abstract

In this paper, we report zinc perchlorate hexahydrate [Zn(ClO₄)₂?6H₂O] as a highly effective catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. These improved reaction conditions allow the preparation of a wide variety of substituted dihydropyrimidinones in high yields and purity under mild reaction conditions. Compared with the classical Biginelli reaction, this method has the advantage of excellent yields and short reaction time in solvent-free conditions.     

Solvent-free synthesis of 4-aryl substituted 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridones under microwave irradiation

4-Aryl substituted 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridones have been prepared in one-pot condensation from Meldrum's acid, methyl acetoacetate and the appropriate benzaldehyde in the presence of ammonium acetate using microwave irradiation without solvent. This rapid method produced pure products in high yields (81-91%) due essentially to a specific non-thermal microwave effect (17-28%) by conventional heating under the same conditions.     

Synthesis of 4—Aryl—3,4—dihydropyrimidinones Using Microwaveassisted Solventless Biginelli Reaction

Ｉｎｔｒｏｄｕｃｔｉｏｎ4 Ａｒｙｌ 3,4 ｄｉｈｙｄｒｏｐｙｒｉｍｉｄｉｎｏｎｅｓ (4)ａｓａｃｏｒｅｗｅｒｅｏｂｓｅｒｖｅｄｉｎｓｏｍｅｂｉｏｌｏｇｉｃａｌｌｙｉｍｐｏｒｔａｎｔｃｏｍｐｏｕｎｄｓ .1Ｍｏｒｅｒｅｃｅｎｔｌｙ ,ｄｉｈｙｄｒｏｐｙｒｉｍｉｄｉｎｏｎｅｓａｒｅｓｈｏｗｎｔｏｂｅａｕｓｅｆｕｌｔｏｏｌｆｏｒｓｔｕｄｙｉｎｇｄｙｎａｍｉｃｃｅｌｌｕｌａｒｐｒｏｃｅｓｓａｎｄｃａｎｂｅｃｏｎｓｉｄｅｒｅｄａｓａｎｅｗｌｅａｄｆｏｒｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆａｎｔｉ ｃａｎｃｅｒｄｒｕｇ…     

Synthesis and kinetic resolution of furyl substituted secondary carbinols by porcine pancreatic lipase under solvent free conditions

Chiral furyl substituted carbinols were prepared from the related carbonyl compounds and their enzymatic kinetic resolution was studied by using porcine pancreatic lipase (PPL) in transesterification reaction under solvent free condition. This study revealed that carbinols having one less bulky group on the chiral center are good substrates for PPL and the resolution proceeds with higher ee,s and less reaction time.     

General and Green Synthesis of C-6 Sulfonylmethyl 4-Aryl-3,4-dihydropyrimidinones in Water

A simple, inexpensive, and green reaction permitting the synthesis of new C-6 arylsulfonylmethyl 4-aryl-3,4-dihydropyrimidinones in water by S-alkylation of 6-bromomethyl 3,4-dihydropyrimidinones 2 with benzenesulfinic acid anions 3 is reported. The required 6-bromomethyldihydropyrimidone precursors 2 were readily prepared using an organic solid brominating reagent.     

Synthesis and cytotoxic activity of some novel benzocoumarin derivatives under solvent free conditions

In the present study, a rapid, less expensive, clean and environmental friendly route to synthesis new pyrazoles, pyrazolopyridazines and condensed pyrimidines was developed via grinding of 2-(3-(dimethylamino)acryloyl)-3H-benzo[f]chromen-3-one (1) with different reagents. All the new compounds were characterized and established using elemental analysis and spectral data. Eight compounds were selected for in vitro antiproliferative against different human cancer cell lines entitled melanoma, cancers of the lung, leukemia, breast, brain, colon, prostate, ovary and kidney by the USA NCI.     

Synthesis of aurones under neutral conditions using a deep eutectic solvent

Aurones are an interesting, but little studied member of the flavanoid family of natural products. Of the various methods available for their synthesis, the simplest involves the condensation of a coumaranone with an aldehyde. This reaction can be performed under acidic or basic conditions. We have recently discovered an effectively neutral set of conditions that employ the deep eutectic solvent comprised of choline chloride and urea as both solvent and catalyst. Modest to good yields can be achieved for a range of aldehydes, thereby facilitating further study of aurones from both a biological as well as a spectroscopic perspective.     

Synthesis of 1,4-dihydropyridines under solvent free conditions and investigation of their photo physical properties

Synthesis of five 4-aryl substituted 1,4-dihydropyridines was developed following condensation of multi component reaction strategy using yttrium triflate as a catalyst. The absorption and fluorescence properties of structurally related 4-aryl 1,4-dihydropyridines in different solvents of varied polarities was investigated. The absorption maxima of these compounds follow no order of solvent polarity and nature of substitution. The spectral characteristics are solvent and compound specific. Fluorophores with electron withdrawing group have larger fluorescence quantum yields and greater solvatochromism than the compounds with electron donating groups. Protic solvents yielded higher fluorescence quantum efficiency. The chemical shift of the proton attached to C-4 and the carbonyl stretching frequency of bis acetyl groups at 3 and 5-positions exhibited a linear relationship with Hammett's para substituent constants while no such relationship exists between the latter and electronic absorption maxima, fluorescence emission maxima, fluorescence quantum efficiency and Stokes shift.     

Synthesis of substituted 4-acetylamino-4-phenylpiperidines from the corresponding 4-piperidols under Ritter reaction conditions

The reaction of substituted 4-phenyl-4-piperidols with acetonitrile under Ritter reaction conditions leads to formation of mixtures of the corresponding 4-acetylamino-4-phenylpiperidines and 1,2,5,6-tetrahydropyridines, from which we isolated the target amides by fractional crystallization.M. V. Lomonosov State Academy of Fine Chemical Technology, Moscow 117571. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 776–780, June, 1997.     

5-芳基-1,3,4-噻二唑-2-胺衍生物的合成

在冰醋酸催化下,芳香醛(2a～2g)分别和氨基硫脲(3)反应合成得到芳亚胺基硫脲衍生物(4a～4g),中间体4无需经柱层析纯化,然后在三氯化铁作用下反应关环,得到7个目标化合物5-芳基-1,3,4-噻二唑-2-胺(1a～1g).产物结构经1 H NMR、13 C NMR和ESI-MS确证.然后分别以中间体(E)-2-苄...     

Heteropoly acid supported on activated natural clay-catalyzed synthesis of 3,4-dihydropyrimidinones/thiones through Biginelli reaction under solvent-free conditions

Dihydropyrimidinones/thiones (DHPM’s) have been prepared by one-pot condensation of methyl acetoacetate, aldehydes, urea/thiourea in the presence of heteropoly-11-tungsto-1-vanadophosphoric acid, H₄[PVW₁₁O₄₀]?·?32H₂O, (HPV) supported on activated natural clay (HPVAC) under solvent-free reaction condition have been proposed. The DHPM derivatives were identified through elemental analysis and melting point measurements and characterized by FT-IR, ¹H-NMR, ¹³C-NMR spectroscopic methods.     

Synthesis of hexacyclic fused isocoumarin framework through selective domino multicyclizations under catalyst and solvent free conditions

A novel fused isocoumarin skeleton has been synthesized through selective domino multicyclizations by mixing homothallic acid and 2,3-diphenylacryloyl chloride at 200℃ under catalyst and solvent free reaction conditions. Six fused rings with two stereogenic centers were assembled in a convenient onepot operation in good yield. The resulting hexacyclic fused isocoumarin skeleton and its stereochemistry was fully characterized and unambiguously confirmed by X-ray diffraction analysis.     

Synthesis of 1,8-dioxo-decahydroacridine derivatives using sulfonic acid functionalized silica (SiO2-Pr-SO3H) under solvent free conditions

Sulfonic acid functionlized silica (SiO₂-Pr-SO₃H) was found to be an efficient and recyclable solid acid catalyst in the synthesis of 1,8-dioxo-decahydroacridine derivatives under solvent free conditions. Short reaction time, excellent yields and simple work-up are the advantages of this procedure.     

Microwave-assisted chemoselective copper-catalyzed amination of o-chloro and o-bromobenzoic acids using aromatic amines under solvent free conditions

Copper-catalyzed synthesis of N-aryl anthranilic acid derivatives using effective amination of 2-chloro and 2-bromobenzoic acid under microwave irradiation is reported.Some of the advantages of this method are high chemoselectivity,short reaction times,ease of work up procedure and elimination of the need for acid protection.     

Organocatalysed three-component domino synthesis of 1,4-dihydropyridines under solvent free conditions

An organocatalysed protocol for one-pot synthesis of 1,4-dihydropyridines via three-component coupling of cinnamaldehyde, aniline and β-keto esters under solvent free conditions at ambient temperature is reported. The reaction is generally very fast and the products are obtained in high yield. The catalytic activity of small organic molecules like amino acids (acidic, basic and neutral), ephedrine and cinchona alkaloids was studied.     

Novel hexahydrofuro[3,4-b]-2(1H)-pyridones from 4-aryl substituted 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridones

The title compounds 6 have been prepared in a one-step procedure from the corresponding 4-aryl substituted 5-alkoxycarbonyl-6-methyl-3,4-dihydropyridones 4 in good yields. Quantum chemical calculations reveal a non-planar molecule with a distorted dihydropyridone ring and two favoured conformations. The 13C nmr data and theoretical calculations support a strong push-pull effect on the olefinic moiety.     

Green synthesis of 3,4-dihydropyrimidinones using nano Fe3O4@meglumine sulfonic acid as a new efficient solid acid catalyst under microwave irradiation

Design, synthesis and characterization of nano Fe₃O₄@meglumine sulfonic acid as a new solid acid catalyst for the simple and green one pot multicomponent synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones was studied. New solid acid catalyst was prepared through a clean and simple protocol and characterized using FTIR, VSM, TGA, SEM, elemental analysis (CHN) and XRD techniques. Heterogenization of homogeneous catalyst as a green approach is a useful method for enhancing the efficiency of catalyst. Presented study was a new method for attachment of homogeneous highly soluble catalyst (meglumine sulfate) to the magnetite nanoparticle surfaces for preparing a heterogeneous and effective catalyst. Obtained heterogeneous and reusable solid acid catalyst has high performance in the synthesis of Biginelli compounds. The reaction was performed under microwave irradiation as a rapid and green condition. Easy work up as well as excellent yield (90–98%) of products in short reaction times (40–200 s) and reusable catalyst are the main advantages of presented procedure. Reaction products were characterized in details using physical and chemical techniques such as melting point, ¹H NMR, ¹³C NMR and FTIR.     

Palladium-catalyzed addition of disulfides and diselenides to alkynes under solvent free conditions

An efficient methodology was developed for performing palladium-catalyzed E-E (E = S, Se) bond addition to alkynes under solvent free conditions. Compared to reaction in solvent significant enhancement of reaction rate, improved efficiency and remarkable catalyst stability were observed under solvent free conditions. The addition reactions were carried out with high stereoselectivity and yields in a short reaction time.     

Dowex-promoted general synthesis of N,N′-disubstituted-4-aryl-3,4-dihydropyrimidinones using a solvent-free Biginelli condensation protocol

Dowex-50W ion exchange resin-promoted solvent-free heating of an intimate mixture of an aldehyde, an active methylene compound and N,N′-dimethylurea furnished the title compounds in moderate to good yields.     

Synthesis of 3-aryl substituted benzo[1,2,5]triazepin-4-ones via intramolecular imine formation

3-Aryl substituted benzo[1,2,5]triazepin-4-ones and their pyrido counterparts have been synthesized in five steps from commercially available starting materials. The key step involves base-induced cleavage of trifluoroacetyl-protected hydrazine intermediates and in situ intramolecular imine formation.