نتایج جستجو برای: cyclocondensation
تعداد نتایج: 265 فیلتر نتایج به سال:
substituted schiff's bases 2a-o prepared by the treatment of 2-amino-4-(?-methoxyiminocarbomethoxymethyl)-thiazole 1 with different aromatic aldehydes, on cyclocondensation with mercaptoaceticacid and mercaptopropionicacid in dry benzene furnished desired thiazolidinones of type 3a-o and 4a-j, respectively. the structure of the compounds have been assigned on the basis of elemental analyse...
decatungstodivanadogermanic acid (h6gew10v2o40.22h2o) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1h)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. this method provides an efficient and much improved modification of the original biginelli reaction...
Total syntheses of (+)-cinereain and (−)-janoxepin, two fungal cyclotripeptides featuring a complex heterocyclic core interesting phytotoxic antimalarial activities, have been achieved in convergent manner. A key step this synthesis is one-pot cascade initiated by the cyclocondensation fragments—a hindered 2-vinylcyclopropane-1-acyl fluoride an electron-deficient cyclic amidine—to release react...
3-Acylmethylidene-3,4-dihydroquinoxalin-2(1H)-ones are compounds which possess a wide range of physical and pharmaceutical applications. These compounds can be easily prepared by cyclocondensation of o-phenylenediamines and aroylpyruvates. Unsymmetrically substituted o-phenylenediamines can be obtained form regioisomeric mixtures of 3,4-dihydroquinoxalin-2(1H)-ones. It is often quite difficult ...
New pyrimido [4, 5-e] [1, 3, 4]thia- diazin-7-yl] hydrazines were synthesized via the cyclocondensation of alkyl-2-phenylhydrazinecarbodithioates as a binucleophile with 5-bromo-2,4-dichloro-6-methylpyrimidine as a bielectrophile , and replacement of C-7 chloro atom by hydrazine in ethanol as the solvent . This method has advantages over methods currently described in the literature for the con...
The title isochroman ( 8 ) was synthesized as a suitable substrate for acetoxylation studies leading to an intermediate of type (4), expected to afford, on condensation with diketen, the fungal metabolite "rotiorin" type linear product (1). Cyclocondensation of alcohol (6), obtained by the reduction of ketone (5) with paraform in the presence of anhydrous aluminum chloride afforded the dim...
In the present work, we have developed a mild, efficient, and environmentally benign method for the synthesis of tetrahydrobenzo[b]pyran derivatives via a three-component cyclocondensation of aldehydes, malononitrile and dimedone utilizing ammonium chloride as a simple, easily available and cost effective catalyst under microwave irradiation. This method has several attracting features such as ...
Decatungstodivanadogermanic acid (H6GeW10V2O40.22H2O) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. This method provides an efficient and much improved modification of the original Biginelli reaction...
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