Search

A simple, efficient and environmentally friendly process for the solid state synthesis of quinoxaline derivatives by the condensation reaction of the benzo[c][1,2,5]thiadiazole-4,5-diamine and 3-(ω-bromoacetyl)-coumarins in the presence of cellulose sulfuric acid by simple physical grinding of reactants using a mortar and pestle at room temperature in good to excellent yields with high purity. The catalyst is recyclable and reusable. [ABSTRACT FROM PUBLISHER]

A simple and efficient method has been developed for the synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) by the condensation reaction between substituted aldehydes, and 1-phenyl-3-methylpyrazol-5-one in the presence of xanthan sulfuric acid (XSA) as a solid acid catalyst. This method is simple and cost-effective with short reaction times. Yields are excellent with high purity, and the catalyst could be easily recycled. [ABSTRACT FROM AUTHOR]

In this report, substituted coumarins are formed via Pechmann condensation using various substituted phenols and ethyl acetoacetates in the presence of xanthan sulfuric acid as a solid acid catalyst under solvent-free conditions. This method is very simple, cost-effective, and has shorter reaction times, and the catalyst could be reused. [ABSTRACT FROM PUBLISHER]

Xanthan sulfuric acid (XSA) is employed as a recyclable catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones. These syntheses were performed via a one-pot, three-component condensation of aldehydes, amines, and urea/thiourea under solvent-free conditions. [ABSTRACT FROM AUTHOR]

[image omitted] A series of 1-oxo-hexahydroxanthene derivatives was synthesized at room temperature in solid state from substituted salicylaldehydes and substituted 1,3-hexanediones in the presence of a catalytic amount of cellulose sulfuric acid. The results showed that the reaction performed under solid-state conditions was benign to the environment, with higher yields and more convenient workup. [ABSTRACT FROM AUTHOR]

(5-Acetyl-6-hydroxy-3-methylbenzofuran-2-carbonyl)-chromene-2-one, paraformaldehyde, and morpholine furnished the mannich base 3-[6-hydroxy 3-methyl-5-(3-morpholin-4-yl-propionyl)-benzofuran-2 carbonyl]-chromen-2-one.This mannich base is irradiated with various chloro-substituted amines afforded 3-[6-(2-amino-ethoxy)-3-methyl-5-(3-morpholin-4-yl-propionyl)-benzofuran-2 carbonyl]-chromen-2-one in good yields.[image omitted] [ABSTRACT FROM AUTHOR]

[image omitted] An efficient method for the synthesis of 2-substituted benzimidazoles has been developed. In this method, benzo[c][1,2,5]thiadiazole-4,5-diamine was condensed with different aldehydes in the presence of cellulose sulfuric acid under solvent-free conditions by simple physical grinding of reactants using a mortar and pestle at room temperature. The methodology is mild, high-yielding, and green, and the catalyst could be easily recycled. [ABSTRACT FROM AUTHOR]

A facile synthesis of coumarins was performed in excellent yields via Pechmann condensation by using different type of phenols and ethylacetoacetates under solvent-free media using both conventional method and microwave irradiation in short reaction times is described. The reaction workup is very simple, and the catalyst can be easily separated from the reaction mixture and reused several times in subsequent reactions. [ABSTRACT FROM AUTHOR]

A convenient, scalable, and commercially viable process for the production of the antidepressant drug bupropion hydrochloride (1) is reported. The process relies upon an improved, large-scale synthesis of the key intermediate, m-chloro-α-bromopropiophenone (4). During process development, bromine was replaced with N-bromosuccinimide (NBS) in the presence of para-toluene sulfonic acid (p-TSA), for the bromination of m-chloropropiophenone (3), in either a very low volume of acetonitrile or under solvent-free conditions, to furnish 4. Intermediate 4 was further reacted with t-butylamine in N-methyl-2-pyrrolidinone (NMP) to afford bupropion free base (5), followed by treatment with a saturated solution of hydrochloric acid in isopropyl alcohol (IPA-HCl) to afford bupropion hydrochloride (1). This improved process provides pure bupropion hydrochloride (1) in good yields and at considerably lower cost than existing processes, and it does not involve the use of hazardous reagents. [ABSTRACT FROM AUTHOR]

Biosupported cellulose sulfuric acid has been found to be an efficient solid acid catalyst for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. The advantages of this method are avoidance of harsh reaction conditions, ecofriendly chemistry, operational simplicity, high yield, and reusable catalyst. [ABSTRACT FROM AUTHOR]

This article explores the use of sulfamic acid as an efficient catalyst for the one-pot synthesis of thiadiazolo 1, 5 benzodiazepines by using benzo[c][1,2,5]thiadiazole-4,5-diamine and various types of ketones in the presence of chloroform as a solvent under conventional methods and microwave irradiation. Our method is more advantageous than current methods. The catalyst (sulfamic acid) is cost effective, readily available and gives excellent yields with high purity. In comparison, the microwave irradiation method is equally as effective with a shorter reaction time and still maintaining high yields. [ABSTRACT FROM AUTHOR]

1,3-Selenazoles were Synthesized from 3-bromo acetyl coumarin and selenourea in the presence of CuPy2Cl2 under solvent-free conditions at ambient temperature. The pure products were identified by spectral data. [ABSTRACT FROM AUTHOR]

An efficient and convenient method is described for the synthesis of 1,8-naphthyridines in excellent yields by condensation of 2-aminonicotinaldehyde with various active methylene compounds in the presence of sulfamic acid as the catalyst in a solvent-free media using both conventional heating and microwave irradiation. [ABSTRACT FROM AUTHOR]

CuPy2Cl2 is an efficient catalyst for the preparation of propargylamines via three-component coupling reaction of aromatic aldehydes, amines, and aromatic alkynes stirred at 95 °C without using any solvent to afford the corresponding products in good yields. The reaction mixture was irradiated at 450 W in a microwave oven to furnish the expected products in excellent yields. [ABSTRACT FROM AUTHOR]

An efficient and convenient method for the synthesis of substituted coumarins via Pechmann condensation of different phenols with ethylacetoacetate in the presence of ammonium cerium(IV) nitrate as the catalyst in a solvent- free media using both conventional heating and microwave irradiation. [ABSTRACT FROM AUTHOR]

A rapid and efficient method for the preparation of 3-(4,6-dimethyl-oxazolo[4,5-c]quinolin-2-yl)-chromen-2-ones by the reaction between 3-amino-2,8-dimethyl-quinolin-4-ol and 2-oxo-2H-chromen-3-carboxylic acid using sulfamic acid as a acid catalyst and dimethyl formamide as a solvent using the conventional method and microwave irradiation is reported. [ABSTRACT FROM AUTHOR]

An efficient one-pot synthesis of 3-(2-oxo-2H-chromen-3-yl)-[1,3,4] thiadiazino [2,3-b] quinazolin-6(2H)-ones in high yields has been developed by microwave-induced heterocyclization of 3-amino-2mercapto-3H-quinazolin-4-one when irradiated with 3-(2-bromo-acetyl)-chromen-2-one in ethanol and anhydrous potassium carbonate. A comparative study of conventional and MW methods is briefly discussed. [ABSTRACT FROM AUTHOR]

α-Aminophosphonates are synthesized by three-component condensation of aldehydes, amines, and trimethylphosphite in acetonitrile by using TiCl4 as catalyst. Compared to conventional methods, this new method consistently has advantages, including excellent yields, short reaction times, and mild reaction conditions. [ABSTRACT FROM AUTHOR]

In this article, we describe the synthesis of various substituted Chromene-[1, 3]thiazolo [2, 1, 3] benzothiadiazoles 4a-l by conventional (Method A) and microwave-assisted (Method B) which achieved reductions in reaction times, higher yields, and a cleaner reaction than the conventional method. A comparative study of these two methods has been discussed. [ABSTRACT FROM AUTHOR]

Acrolyl furochromen-2-ones (3a–i) obtained in good yields on microwave irradiation of furochromen-2-one (1) with various simple and substituted aromatic aldehydes (2a–i).3a–gon cyclo dehydration with thiourea in domestic microwave oven furnished tetrahydro thiaxopyrimidine furochromen-2-ones4a–iin high yields. The structures of the newly synthesized compounds were established on the basis of analytical and spectral data, IR, and1H NMR. [ABSTRACT FROM AUTHOR]

An efficient synthesis of 3,4-dihydropyrimidinones(DHPMs) using bismuth subnitrate as the catalyst for the first time from an aldehyde,β-ketoester, and urea in acetonitrile is described. This new method consistently has the advantage of excellent yields(88–96%) and short reaction times(1.5–4 h) than do classical Biginelli reaction conditions. [ABSTRACT FROM AUTHOR]