Alumina supported MoO3: An efficient and reusable heterogeneous catalyst for synthesis of 3,4-dihydropyridine-2(1H)-ones under solvent free conditions

Jain, Suman L.; Prasad, V.V.D.N.; Sain, Bir

doi:10.1016/j.catcom.2007.04.021

Cited by 54 publications

(14 citation statements)

References 27 publications

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“…Nesse sentido a pesquisa de novos materiais semicondutores capazes de degradar com mais eficiência tem sido alvo de interesse de muitos pesquisadores em todo mundo. Dentro desse contexto destaca-se o MoO 3 com band gap de no máximo 3,3 eV [7,8,[11][12][13][14][15][16]. Nesse contexto o estudo sobre o MoO 3 vem atraindo cada vez mais a atenção de pesquisadores em virtude de sua variedade de estruturas, características físico-químicas e seu leque de aplicações, no qual se destaca o uso em catálise [11], baterias [12], sensores de gás [13], tecnologias para dispositivos eletrocrômicos [14,15] e fotodegradação [16].…”

Section: Introductionunclassified

“…Dentro desse contexto destaca-se o MoO 3 com band gap de no máximo 3,3 eV [7,8,[11][12][13][14][15][16]. Nesse contexto o estudo sobre o MoO 3 vem atraindo cada vez mais a atenção de pesquisadores em virtude de sua variedade de estruturas, características físico-químicas e seu leque de aplicações, no qual se destaca o uso em catálise [11], baterias [12], sensores de gás [13], tecnologias para dispositivos eletrocrômicos [14,15] e fotodegradação [16]. O MoO 3 é conhecido por apresentar vários polimorfos, que são divididos em cinco fases: uma fase ortorrômbica α-MoO 3 termodinamicamente estável [17], quatro fases metaestáveis, sendo três monoclínicas β-MoO 3 [18], MoO 3 -II [19] e MoO 3 -III [20], e uma hexagonal h-MoO 3 , além das fases de MoO 3 hidratadas, com fórmula geral MoO 3 .nH 2 O.…”

Section: Introductionunclassified

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Síntese, caracterização e aplicação do trióxido de molibdênio na fotocatálise de efluente têxtil sintético

Silva

Matos

2018

Cerâmica

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ResumoNeste estudo o trióxido de molibdênio (MoO 3 ) foi sintetizado pelo método hidrotérmico com temperatura fixa em 180 ºC nos tempos de 1 e 6 h, seguido de tratamento térmico por 6 e 12 h a 300, 450 e 600 ºC. A fase cristalina e as propriedades estruturais da amostra foram caracterizadas pelo método de difração de raios X. O comportamento vibracional das ligações químicas foi verificado por espectroscopias na região do infravermelho e Raman, em que as bandas e picos observados confirmaram a formação do MoO 3 . A microscopia eletrônica de varredura mostrou a formação de microestruturas da fase hexagonal (h-MoO 3 ) e ortorrômbica (α-MoO 3 ) do MoO 3 . Além disso, as propriedades de absorção óptica foram medidas por espectroscopia de reflectância difusa e os valores de energia de gap foram estimados no intervalo de 2,74 a 3,33 eV a partir da função Kubelka-Munk. Os óxidos calcinados a 600 ºC foram os que apresentaram a melhor atividade fotocatalítica, degradando 50% do corante em 2 h de reação. Palavras-chaves: efluente sintético, fotocatálise, trióxido de molibdênio. Abstract In this study, the molybdenum trioxide (MoO

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Section: Introductionunclassified

Síntese, caracterização e aplicação do trióxido de molibdênio na fotocatálise de efluente têxtil sintético

Silva

Matos

2018

Cerâmica

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“…Recently, the use of heterogeneous catalysts [23][24][25][26] has received considerable importance in organic synthesis because of their ease of handling, enhanced reaction rates, greater selectivity, simple workup, and recoverability of catalysts. Among the various heterogeneous catalysts, particularly, silica gel-supported sulfuric acid [27] has advantages of low cost, ease of preparation, and catalyst recycling.…”

Section: Introductionmentioning

confidence: 99%

Silica gel‐supported sulfuric acid catalyzed synthesis of 1,5‐benzodiazepine derivatives

Shobha

Chari

Mukkanti

et al. 2009

Journal of Heterocyclic Chem

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in Wiley InterScience (www.interscience.wiley.com).Silica gel-supported sulfuric acid has been found to be an efficient catalyst for the synthesis of 1,5-benzodiazepines from o-phenylenediamine and ketones in acetonitrile solvent. This method is simple, effective, and environmentally friendly and gives better yields. Compared to the classical reaction conditions, this new method consistently has the advantage of excellent yields (80-97%) and short reaction time (30-150 min) at room temperature.

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“…To circumvent this problem, a variety of new catalysts has been introduced in the literature. In recent years, many protocols involving the use of Lewis and Bronsted acids such as graphite supported lanthanum chloride, [5] alumina supported MoO 3 [6], antimony(III) chloride [7], copper(II) tetrafl uoroborate [8], bismuth nitrate [9], iron(III) trifl uoroacetate and trifl uoromethanesulfonate [10], yttrium(III) nitrate hexahydrate [11], TaBr 5 [12], Trichloroisocynuric acid (TCCA) [13], PSSA [14], chloroacetic acid [15], p-TsOH [16], HCl [17], acetic acid [18], silica sulfuric acid [19], concentrated H 2 SO 4 [20], H 3 BO 3 [21], HBF 4 [22], chiral phosphoric acid [23], H 3 PW 12 O 40 [24], H 3 PMo 12 O 40 [25], Al 2 O 3 /MeSO 3 H [26], HClO 4 doped silica [27], bentonite/PS-SO 3 H nanocomposite [28], sulfated tungstate [29], imidazol-1-yl-acetic acid [30], zeolite-supported HPA [31] and a number of other catalysts [32][33][34][35][36][37][38] are reported. However, at a practical level, these often require relatively harsh reaction conditions such as high reaction temperatures, expensive or highly acidic catalysts, and prolonged reaction times.…”

Section: Introductionmentioning

confidence: 99%

“…To circumvent this problem, a variety of new catalysts has been introduced in the literature. In recent years, many protocols involving the use of Lewis and Bronsted acids such as graphite supported lanthanum chloride, [5] [32][33][34][35][36][37][38] are reported. However, at a practical level, these often require relatively harsh reaction conditions such as high reaction temperatures, expensive or highly acidic catalysts, and prolonged reaction times.…”

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confidence: 99%

Starch Sulfuric Acid: an Alternative, Eco-Friendly Catalyst for Biginelli Reaction

Rezaei¹,

Malek²,

Sheikhi³

et al. 2013

ChemJMold

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Abstract. The one-pot multicomponent synthesis of 3,4-dihydropyrimidinone derivatives using starch sulfuric acid as an environmentally friendly biopolymer-based solid acid catalyst from aldehydes, β-keto esters and urea/ thiourea without solvent is described. Compared with classical Biginelli reaction conditions, this new method has the advantage of minimizing the cost operational hazards and environmental pollution, good yields, shorter reaction times and simple work-up.Keywords: Biginelli reaction, dihydropyrimidinones, starch sulfuric acid, solvent-free, biodegradable catalyst. IntroductionDihydropyrimidinones are attractive organic compounds which show important biological activities such as antiviral, antitumor, antibacterial and anti-infl ammatory actions [1][2][3]. The more convenient procedure for the preparation of dihydropyrimidinones fi rst reported by P. Biginelli in 1893, consists of the one-pot condensation of β-dicarbonyl compounds with aldehydes and urea or thiourea under strongly acidic conditions [4]. One major disadvantage of this method is the low yields especially in the case of aliphatic and some substituted aromatic aldehydes. To circumvent this problem, a variety of new catalysts has been introduced in the literature. In recent years, many protocols involving the use of Lewis and Bronsted acids such as graphite supported lanthanum chloride, [5] [32][33][34][35][36][37][38] are reported. However, at a practical level, these often require relatively harsh reaction conditions such as high reaction temperatures, expensive or highly acidic catalysts, and prolonged reaction times. In most of the cases stoichiometric amounts of catalyst are required in order to achieve good yields. In addition, most of the reactions require tedious work-up procedures and column purifi cation, which ultimately results in diminished yields. Therefore, in spite of a large number of methods reported for this transformation, there is still need to develop a more effi cient, simple, milder protocol using conservational catalyst.In recent years, the direction of science and technology has been shifting more towards eco-friendly, natural product resources and reusable catalysts. Thus, natural biopolymers are attractive candidates in the search for such solid support catalysts [39]. Starch as a one of the most common and easy to recover biopolymer become in the scope of many research [40, 41].We now report an effi cient catalyzed method for the synthesis of dihydropyrimidinones via the three-component reaction of β-dicarbonyl compounds with aldehydes and urea or thiourea under mild conditions (Scheme 1). To the best of our knowledge, the use of starch sulfuric acid (SSA) as a catalyst for the synthesis of dihydropyrimidinones previously has not been reported.

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Alumina supported MoO3: An efficient and reusable heterogeneous catalyst for synthesis of 3,4-dihydropyridine-2(1H)-ones under solvent free conditions

Cited by 54 publications

References 27 publications

Síntese, caracterização e aplicação do trióxido de molibdênio na fotocatálise de efluente têxtil sintético

Síntese, caracterização e aplicação do trióxido de molibdênio na fotocatálise de efluente têxtil sintético

Silica gel‐supported sulfuric acid catalyzed synthesis of 1,5‐benzodiazepine derivatives

Starch Sulfuric Acid: an Alternative, Eco-Friendly Catalyst for Biginelli Reaction

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