An efficient and green one-pot three-component synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol)s catalyzed by 2-hydroxy ethylammonium propionate

A simple and efficient one-pot synthetic protocol for the 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol)s was developed by condensation reaction of aromatic aldehydes, ethyl acetoacetate, and phenylhydrazine/hydrazine hydrate catalyzed by 2-hydroxy ethylammonium propionate under solvent-free conditions. The remarkable features of this new protocol are high yields, short reaction times, easy workup, reusability of inexpensive ionic liquid, and environmentally benignancy.     

Guanidine hydrochloride catalyzed efficient one-pot pseudo five-component synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) in water

The present methodology describes an efficient, environmentally friendly and simple protocol for the synthesis of some 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol) derivatives through a one-pot pseudo-five-component reaction of hydrazine hydrate/phenyl hydrazine, ethyl acetoacetate, and various aromatic aldehydes catalyzed by guanidine hydrochloride. This condensation reaction was performed by tandem Knoevenagel–Michael reaction in water under refluxing conditions giving the title compounds in 82–92% yields. Atom economy, simple operation, easy work-up, using inexpensive organocatalyst, high yields in short times, clean transformation, and environmentally benign are some of the important features of this new protocol.     

氯化亚锡催化“一锅法”合成N1-取代的3,4-二氢嘧啶-2(1H)-酮

以芳香醛、乙酰乙酸乙酯(甲酯)、单取代脲为原料,氯化亚锡为催化剂,在无溶剂、80℃条件下,通过三组分"一锅法"合成了一系列N1-取代的3,4-二氢嘧啶-2(1H)-酮衍生物。考察了催化剂用量和反应温度对产品收率的影响。通过IR、~1H NMR、~(13)C NMR和元素分析对目标产物结构进行确证,提出了可能的催化作用机理。本文的合成方法具有催化剂活性高、廉价易得和反应时间短、条件温和、产率高、绿色环保等优点。     

SnCl2/nano SiO2：A green and reusable heterogeneous catalyst for the synthesis of polyfunctionalized 4H-pyrans

A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl acetoacetate using nano silica supported tin (Ⅱ) chloride as a catalyst. In this method SnCl2/nano SiO2 was used as green and reusable catalyst. Excellent yields, short reaction times, simple workup, and inexpensiveness and commercially availability of the catalyst are the advantages of this method.     

Unusual product from the acid-catalyzed one-pot,multicomponent reaction of thiocarbohydrazide,aldehydes, and phenacyl bromides

A one-pot, three-component protocol for the synthesis of novel five-membered thiazole ring bonded to two hydrazone motifs is described. The acid-catalyzed reaction of one equivalent of thiocarbohydrazide, two equivalents of aromatic aldehydes, and one equivalent of phenacyl bromides afforded the five-membered thiazole ring. The reactions proceed with novel chemoselectivity. Similar reported protocols have always afforded 1,3,4-thiadiazines.     

Xanthan sulfuric acid: An efficient and biodegradable solid acid catalyst for the synthesis of bis(indolyl)methanes under solvent-free conditions

Xanthan sulfuric acid (XSA) is found to be an efficient catalyst for the electrophilic substitution reaction of indole with aromatic aldehydes to afford the corresponding bis(indolyl)methanes at room temperature under solvent-free conditions. The catalyst was characterized for the first time with the help of powder XRD, SEM–EDX and DSC–TGA. The attractive features of this green, new methodology are excellent yield of products, clean reaction profile, reusability of the catalyst, energy sustainable protocol, simple experimental and easier work-up procedures.     

无溶剂条件下对甲基苯磺酸铝高效催化合成4,6-二芳基-3,4-二氢嘧啶-2(1H)-酮

以芳香醛、芳香酮和尿素为原料,对甲基苯磺酸铝为催化剂,在90_oC、无溶剂条件下“一锅法”反应,高效合成了一系列4,6-二芳基-3,4-二氢嘧啶-2(1H)-酮。产品结构通过IR,₁H NMR,₁₃C NMR和元素分析进行了表征。该方法具有操作简单、反应时间短、产率高、反应条件温和、不使用任何有机溶剂、催化剂廉价易得且可重复使用等优点,为标题化合物的合成提供了一种简便高效的绿色新途径。     

Zn(ANA)2Cl2 complex as efficient catalyst for the synthesis of dihydropyrano[2,3-c]pyrazoles in aqueous medium via one-pot multicomponent reaction: a green approach

Abstract

The first example of recyclable Zn(ANA)₂Cl₂ catalyzed tandem one-pot three-component protocol reaction between aromatic aldehydes, malononitrile, and phenylmethylpyrazolone to furnish 4-substituted-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (4a–l) in a short reaction time (～10?min) in aqueous media at room temperature is described.     

Fe(HSO4)3: An efficient, heterogeneous and reusable catalyst for the synthesis of 14-aryl- or alkyi-14H-dibenzo[a.j]xanthenes

Fe(HSO4)3 has been used as an efficient and reeyclable catalyst for the one-pot synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthene derivatives by the reaction of 2-naphtol and aldehydes. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products were obtained in good to excellent yields.     

氯化铝高效催化合成1-(1-酰胺基)烷基-2-萘酚类化合物

无溶剂条件下,氯化铝可有效催化2-萘酚、醛和胺/尿素三组分"一锅法"合成1-(1-酰胺基)烷基-2-萘酚.考察了溶剂条件和催化剂用量对产率的影响.与已报道的方法相比,该方法具有反应时间短、产率高、实验操作和后处理步骤简单等优点.     

无溶剂条件下方便、有效的方法合成3-氰基-2-吡啶酮衍生物

芳醛、丙酮和氰乙酰胺为原料,氢氧化钠为催化剂,在无溶剂条件下加热反应有效地合成2-吡啶酮衍生物,本方法具有反应时间短、条件温和、处理简单和环境友好等优点.     

Dodecylphosphonic acid (DPA): a highly efficient catalyst for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones under solvent-free conditions

A new green protocol has been developed for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones via one-pot, three-component condensation reaction of aromatic aldehydes with 1,3-dicarbonyl compounds and phthalhydrazide using reusable dodecylphosphonic acid (DPA) as heterogeneous solid acid catalyst under solvent-free conditions. This protocol provides a novel and improved method for obtaining 2H-indazolo[2,1-b]phthalazine-triones in terms of good yields with little catalyst loading.     

Silica supported perchloric acid (HClO4-SiO2): an efficient and recyclable heterogeneous catalyst for the one-pot synthesis of amidoalkyl naphthols

An efficient and direct protocol for the preparation of amidoalkyl naphthols employing a multi-component and one-pot condensation reaction of 2-naphthol, aromatic aldehydes, and acetonitrile or acetamide in the presence of silica supported perchloric acid under solvent, solvent-free, and microwave irradiation conditions is described. The present protocol with HClO₄-SiO₂ catalyst is superior to the recently reported catalytic methods. It is noteworthy that 1-amidomethyl-2-naphthols can be converted into important ‘drug like’ 1-aminomethyl-2-naphthol derivatives by amide hydrolysis.     

A green one-pot synthesis of N-alkyl-2-(2-oxoazepan-1-yl)-2-arylacetamide derivatives via an Ugi four-center,three-component reaction in water

This work describes a green and efficient one-pot synthesis of N-alkyl-2-(2-oxoazepan-1-yl)-2-arylacetamide derivatives via an Ugi four-center, three-component reaction of 6-aminohexanoic acid, aromatic aldehydes, and isocyanide derivatives in water under reflux conditions in the absence of a catalyst.     

(英)硫酸氢钾高效催化一锅法合成5-未取代的3,4-二氢嘧啶-2(1H)-酮

无溶剂条件下,硫酸氢钾可有效催化芳香醛、苯乙酮衍生物和脲的三组分"一锅法"Biginelli反应来合成5-未取代的3,4-二氢嘧啶-2(1H)-酮。确定了优化反应条件。产品结构经IR、1H NMR、MS和元素分析进行表征。     

聚乙烯基吡啶高氯酸盐作为高效固体酸催化剂在无溶剂条件下催化醛化学选择性制备二乙酸盐简

Poly(4-vinylpyridinium) perchlorate has been used as a supported, recyclable, environmentally-benign catalyst for the formation of acylals from aliphatic and aromatic aldehydes in good to excellent yields under solvent-free conditions. Notably, the reaction conditions were tolerant of ketones. This methodology offers several distinct advantages, including its operational simplicity and high product yield, as well as being green in terms of avoiding the use of toxic catalysts and solvents. Furthermore, the catalyst can be recovered and reused several times without any loss in its activity.     

2-Aminoethanesulfonic acid: An efficient organocatalyst for green synthesis of spirooxindole dihydroquinazolinones and novel 1,2-(dihydroquinazolin-3(4H)isonicotinamides in water

Abstract

A facile and efficient one-pot procedure for the preparation of spirooxindole dihydroquinazolinone derivatives and new N-(4-oxo-2-phenyl-1,2-dihydroquinazolin-3(4H)-yl)isonicotinamides from reaction between isatoic anhydride, isoniazid and substituted aldehydes catalyzed by 2-aminoethanesulfonic acid (taurine) is describe. This new protocol has the advantages of environmental friendliness, good yields, and convenient operation. The reaction proceeds efficiently using water as green solvent and nontoxic catalysts that could be efficiently reused. Together with this simple workup procedure, use of the organocatalyst, and water as solvent without the need of column chromatographic purification, are the notable features of this methodology, which make this protocol a very efficient and green alternative to the traditional methods.     

Eco-friendly and efficient multi-component method for preparation of 1-amidoalkyl-2-naphthols under solvent-free conditions by dodecylphosphonic acid (DPA)

An efficient and direct eco-friendly protocol for the preparation of 1-amidoalkyl-2-naphthols employing a multi-component, one-pot condensation reaction between β-naphthol, aromatic or aliphatic aldehydes and benzamide or acetamide in the presence of dodecylphosphonic acid under solvent-free conditions has been described.     

First catalyst- and solvent-free synthesis of 3,4-dihydropyrimidin-2(1<Emphasis Type="Italic">H</Emphasis>)-ones and -thiones

A completely green and environmentally benign Biginelli synthesis of 3,4-dihydropyrimidine-2(1H)-ones and -thiones by one-pot three-component reaction of aromatic aldehydes with ethyl acetoacetate and urea or thiourea without any catalyst under solvent-free conditions is described.     

Ionic Liquid–Catalyzed One-Pot Synthesis of 1H-Pyrano[2,3-d]pyrimidin-2(8aH)-one Derivatives via Three-Component Reaction under Solvent-Free Conditions

A series of 1H-pyrano[2,3-d]pyrimidin-2(8aH)-one derivatives were synthesized via one-pot, three-component reaction of aromatic aldehydes, urea or thiourea, and 3,4-dihydro-2H-pyran using the green and inexpensive Brønsted acidic ionic liquid 1-methyl-2-pyrrolidinone hydrosulfate ([Hnmp]HSO₄) as catalyst under solvent-free conditions. The method has several advantages such as mild conditions, shorter reaction time, good yields, and environmentally benign procedure. Moreover, the catalyst could be recovered conveniently and reused at least four times without evident loss of activity.