Organic chemistry
Asadollah Farhadi; Mohammad Ali Takassi; Lila Hejazi
Volume 5, Issue 1, pp. 1-120, Serial No. 14 , January 2017, , Pages 35-41
Abstract
The chemistry of 2-oxo-1,2,3,4-tetrahydropyrimidines began to develop toward the end of 1893 year, when the first representatives of this class compounds were reported by P. Biginelli. Despite prior reports of several really effective catalytic and non-catalytic approaches towards Biginelli-type products, ...
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The chemistry of 2-oxo-1,2,3,4-tetrahydropyrimidines began to develop toward the end of 1893 year, when the first representatives of this class compounds were reported by P. Biginelli. Despite prior reports of several really effective catalytic and non-catalytic approaches towards Biginelli-type products, an overwhelming number of new catalysts for the Biginelli reaction have been recently published. Most of the catalysts are somewhat exotic, expensive, harmful and even ineffective in the absence of acidic additives. This work reports on the preparation of 2-oxo-1,2,3,4-tetrahydropyrimidines using the NaF as catalyst. One-pot condensation reactions were carried out for various aryl aldehydes, ethyl acetoacetate, acetyl acetone and urea under solvent-free conditions at 100 °C and afforded the target molecules in good to excellent yields. The advantages of this method are high yield of product, short reaction time, and separation of this catalyst is very comfortable. Furthermore, according to the experimental data, we have proposed the suitable mechanism.
Organic chemistry
Saeid Azimi; Marziyeh Hariri
Volume 4, Issue 1, pp. 1-132, Serial No. 10 , January 2016, , Pages 13-20
Abstract
In this work, the ionic liquid triethylamine-bonded sulfonic acid {[Et3N–SO3H]Cl}, N,N-diethyl-N-sulfoethanammonium chloride was used as a green acidic homogeneous catalyst to synthesis of 3,4-dihydropyrimidin-2(1H)-ones and 3,4-dihydropyrimidin-2(1H)-thiones as two categories of heterocycles, ...
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In this work, the ionic liquid triethylamine-bonded sulfonic acid {[Et3N–SO3H]Cl}, N,N-diethyl-N-sulfoethanammonium chloride was used as a green acidic homogeneous catalyst to synthesis of 3,4-dihydropyrimidin-2(1H)-ones and 3,4-dihydropyrimidin-2(1H)-thiones as two categories of heterocycles, from aldehyde, dicarbonyl compound and urea or thiourea throughout the one-pot three components cyclocondensation reactions. The dihidropyrimidineones and dihydropyrimidinethiones derivatives that synthesized in this method are two important categories of heterocyclic compounds with biologic and pharmacologic activity. The ionic liquid that used in these reactions act as Bronsted acid and green homogeneous catalyst and has N-S bond in its cationic fragment and easily synthesised. The advantages of our method are solvent-free conditions, green process and high isolated yield of products.
Organic chemistry
Parya Nasehi; Alireza Kiasat; Mohammad Kazem Mohammadi
Volume 2, Issue 3, pp. 162-231, Serial No. 4 , July 2014, , Pages 180-186
Abstract
3,4-dihydropyrimidin-2(1H)-thiones were synthesized in the presence of Ag nanoparticle/melamine sulfonic acid (MSA) supported on silica gel. The reaction was carried out at 110 oC for 20 min under solvent free conditions. In all cases, the three component reaction proceeded smoothly to give the corresponding ...
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3,4-dihydropyrimidin-2(1H)-thiones were synthesized in the presence of Ag nanoparticle/melamine sulfonic acid (MSA) supported on silica gel. The reaction was carried out at 110 oC for 20 min under solvent free conditions. In all cases, the three component reaction proceeded smoothly to give the corresponding 3,4-dihydropyrimidin-2(1H)-thiones in moderate to good yield. We have found the best conditions are using 0.2 g MSA, 0.05 g Ag nanoparticle.SiO2 under solvent free conditions at 110 oC. This method have some advantages such as good yield, mild reaction conditions, ease of operation and work up, short reaction time and high product purity. In this work, we have investigated the application of Ag nanoparticle/MSA.SiO2 for synthesis of Biginelli – type condensation.