碱性离子液体催化“一锅法”合成1,4-二氢吡喃并[2,3-c]吡唑

在碱性离子液体氢氧化1-丁基-3-甲基咪唑([bmim]OH)催化作用下,由芳香醛、丙二腈、苯甲酰乙酸乙酯和肼或苯肼"一锅法"合成了一系列1,4-二氢吡喃并[2,3-c]吡唑化合物.实验中考察了催化剂、反应温度、催化剂用量、溶剂对反应的影响,确定了最优反应条件,给出了可能的反应机理.此外催化剂可以方便地收回,且循环使用四次其催化活性并没有显著降低.目标产物经过了1H NMR,IR,MS和元素分析确证.合成方法条件温和、反应时间短、产率高且对环境友好.     

An Efficient Four-Component Synthesis of Multisubstituted Pyrano[2,3-c]pyrazole

A series of substituted pyrano[2,3-c]pyrazole derivatives were synthesized by a one-pot reaction of methyl 4-methyl-3-oxovalerate, phenylhydrazine, aromatic aldehyde, and malononitrile in ethanol with catalysis by triethylamine. The title compounds were obtained in good to excellent yields. A possible mechanism for this reaction was proposed.     

InCl3-Assisted Synthesis of Pyrano[2,3-a]carbazoles via Multicomponent Reaction

A facile, efficient, and environmentally friendly protocol for the synthesis of pyrano[2,3-a]carbazoles has been developed by one-pot multicomponent reaction of benzaldehyde/isatin with malononitrile and 1-hydroxycarbazoles in the presence of InCl₃ as catalyst.     

Design and Synthesis of Pyrano[2,3-a]carbazoles by Multicomponent Reaction

A facile, efficient, three-component reaction of 2,3,4,9-tetrahydro-1H-carbazol-1-one, malononitrile, and aromatic/heteroaromatic aldehydes in dimethylformamide (DMF) gave pyrano[2,3-a]carbazoles in good yields, at reflux condition, using a catalytic amount of piperidine.     

Polyethylene glycol-promoted synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives in water

Synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives were achieved using polyethylene glycol (PEG-400) as promoting reaction medium in water under catalyst-free conditions at reflux and room temperature, respectively. The structure of pyrimido[1,2-a]benzimidazole was confirmed using ¹H NMR, ¹³C NMR, DEPT, and HMBC experiments. The promising points for the present methodology are efficiency, generality, high yield, short reaction time, cleaner reaction profile, ease of product isolation, simplicity, potential of recycling reaction medium, and finally agreement with green chemistry protocols.     

水中吡喃并[2,3-d]嘧啶衍生物的洁净合成

以芳醛、丙二腈和2-氨基-4,6-二羟基嘧啶为原料, 以水为溶剂, 在80 ℃以苄基三甲基溴化铵为催化剂一步合成了一系列的吡喃并[2,3-d]嘧啶衍生物, 产物的结构通过IR, 1H NMR和元素分析表征. 该方法反应条件温和、操作简单、收率高. 而且水作为反应溶剂具有廉价、安全、无污染、产物易于分离的优点.     

Efficient atom-economic one-pot multicomponent synthesis of benzylpyrazolyl coumarins and novel pyrano[2,3-c]pyrazoles catalysed by 2-aminoethanesulfonic acid (taurine) as a bio-organic catalyst

The present work describes eco-friendly multicomponent protocol for the synthesis in excellent yields of structurally diverse benzylpyrazolyl coumarin 5 (a–s) involving the reaction of 4-hydroxycoumarin, ethyl acetoacetate, hydrazine hydrate/phenyl hydrazine hydrate and aldehydes, also novel pyrano[2,3-c]pyrazole derivatives 8 (a–k) integrated by isonicotinic acid hydrazide from reaction of aldehyde, ethyl acetoacetate, malononitrile with isoniazid, employing water as a reaction medium and 2-aminoethanesulfonic acid (taurine) as the catalyst. This new methodology endowed the advantages such as short reaction time, recovery of catalysts after catalytic reaction and reusing them without losing their activity and alleviate of operation.     

四组分一锅法合成多取代吡喃[2,3-c]吡唑-5-腈

在三乙胺催化下,以乙酰乙酸甲酯、苯肼、芳醛和丙二腈等4组分为原料,经一锅法合成了一系列多取代的吡喃并[2,3-c]吡唑衍生物(5a～5j),反应在10～15 min内即可完成.所有产物由IR、1HNMR和MS确证.该方法具有产率高、操作简单等优点.     

Theophylline as a new and green catalyst for the one-pot synthesis of spiro[benzo[a]pyrano[2,3-c]phenazine] and benzo[a]pyrano[2,3-c]phenazine derivatives under solvent-free conditions

A green, convenient, high yielding and one-pot procedure for the synthesis of novel spiro[benzo[a]pyrano[2,3-c]phenazine] derivatives by domino multi-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, ninhydrine, and malononitrile in the presence of a catalytic amount of 1,3-dimethyl-7H-purine-2,6-dione (theophylline) as an expedient, eco-friendly and reusable solid base catalyst under thermal, microwave irradiation and solvent-free conditions. This procedure has also been applied successfully for the synthesis of benzo[a]pyrano[2,3-c]phenazines.     

Convergent Synthetic Route to Pyrano[2,3-a]carbazole by Multicomponent Reaction

NaHCO₃ has been found to be an efficient base catalyst for the synthesis of pyrano[2,3-a]carbazoles from 1-hydroxycarbazoles by multicomponent reaction using solvent-free grinding methods. In this case, the products have been found in good yields, without formation of any side product.     

One-Pot Synthesis of Novel Spiro Pyrano[2,3-d][1,3]thiazolo[3,2-a]pyrimidine Derivatives

In a one-pot synthesis, 1′-methyl-2,3″-dioxo-5″-aryl-1,2,5a″,7″,8″,9a″-hexahydro-5″H,6″H-dispiro[indole-3,2′-pyrrolidine-3′,2″-pyrano[2,3-d][1,3]thiazolo[3,2-a]pyrimidine]-4′-carboxylic acid methyl ester was prepared via the sequential reaction of 4-aryl-octahydro-pyrano[2,3-d]pyrimidine-2-thione, dimethyl acetylenedicarboxylate (DMAD), and a mixture of isatin and sarcosine. All the novel spiro compounds, in moderate yields, were characterized thoroughly by infrared, NMR, mass spectromentry, and elemental analysis together with x-ray crystallographic analysis.     

超声辐射下水介质中三组分一锅合成吡喃并[2,3-d]嘧啶衍生物

报道了在超声波辐射下, 水相中无催化剂下通过芳香醛与丙二腈、巴比妥酸的一锅反应, 合成了一系列吡喃并[2,3-d]嘧啶衍生物. 在超声波辐射下, 不仅饱和芳香醛与丙二腈、巴比妥酸的一锅反应在室温下能高收率地进行, 而对于α,β-不饱和醛以及二元醛与丙二腈、巴比妥酸的一锅反应也能在室温下顺利进行, 获得较高的收率. 产物的结构通过IR, 1H NMR和元素分析表征. 该方法具有操作简单和环境友好等优点.     

水介质中吡喃并[3,2-c]吡喃-5-酮衍生物的三组分一锅合成

水介质中在氯化三乙基苄基铵(TEBAC)催化下, 芳醛与丙二腈和4-羟基-6-甲基吡喃-2-酮三组分一锅反应合成了一系列2-氨基-3-氰基-4-芳基-4H,5H-吡喃-5-酮. 该反应具有产率高、污染少、操作简单、环境友好等优点.     

Novel Synthesis of Thieno[2,3-c]Pyridazine and Pyrimido[4',5':4,5]thieno[2,3-c]pyridazine Derivatives

Abstract

Novel series of thieno[2,3-c]pyridazines and pyrimido[4′,5′:4,5] thieno-[2,3-c]pyridazines have been synthesized from the readily accessible 4-cyano-5,6-dimethylpyridazin-3(2H)-thione 3b.     

Synthesis of furo[3,2-c]- and pyrano[3,2-c]quinolines by lanthanide triflate catalyzed imino-Diels-Alder reaction

Imino Diels-Alder reaction of imines with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran proceeded smoothly in the presence of a catalytic amount (0.5 mol %) of ytterbium triflate to afford furo[3,2-c]- and pyrano[3,2-c] quinolines conveniently in high yield.     

Synthesis of New Benzopyrano[2,3-c]pyrazoles and 3-triazolonyliminocoumarins From 3-cyano Iminocoumarin Derivatives

Synthesis of benzopyrano[2,3-c]pyrazoles and 3-triazolonyliminocoumarins was successfully performed using heterocyclization of 3-cyano iminocoumarin or their N-ethoxycarbonylated derivatives with semicarbazide reagents. Elemental analysis, infrared, and ¹H NMR spectral data confirmed the molecular structure of the newly synthesized compounds.     

Synthesis of 6-Amino-2,4-dihydropyrano[2,3-c]pyrazol-5-carbonitriles Catalyzed by Silica-Supported Tetramethylguanidine Under Solvent-Free Conditions

An efficient, high-yielding, and rapid protocol has been developed for the synthesis of diversity-oriented 6-amino-2,4-dihydropyrano[2,3-c]pyrazol-5-carbonitriles derivatives via a four-component, one-pot cyclocondensation reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes, and malononitrile using silica-supported tetramethylguanidine as a heterogeneous catalyst for the first time. The protocol proves to be efficient and environmentally benign in terms of very easy workup, good yields, and ease of recovery of catalyst. In addition, the present method is superior in terms of green media, the amount of catalyst, and reaction time.     

水中3-甲基-6-氨基-5-氰基-4-芳基-1-苯基-1，4-二氢吡喃[2，3-c]吡唑的洁净合成

在水溶剂中并有三乙基苄基氯化铵（TEBA）存在下，取代芳亚甲基丙二腈与3- 甲基-1-苯基-2-吡唑啉-5-酮缩合成为3-甲基-6-氨基-5-氰基-4-芳基-1-苯基-1， 4-二氢吡喃[2,3-c]吡唑，此法为相应化合物的合成提供了一种快速、方便、高效 和洁净的方法。     

3-甲基-5-氰基-6-氨基-1-苯基-4-(3,4-二甲氧基苯基)-1,4-二氢吡喃[2,3-c]吡唑的合成和晶体结构

标题化合物C22H20N4O3 3是由2-氰基-3-(3,4-二甲氧基苯基)丙烯腈1和3-甲基-1-苯基-2-吡唑-5-酮2在KF-Al2O3催化下在N,N-二甲基甲酰胺(DMF)溶剂中反应而得。结构通过单晶X-射线衍射分析确定,其晶体属于三斜晶系,空间群Pī,a = 9.450(3),b = 10.876(2), c = 11.435(2) ,a = 115.51(1), b = 102.82(1),g = 98.47(2), Mr = 388.42, V = 994.1(3) 3,Dc = 1.298 g/cm3, Z = 2, m (MoKa) = 0.089 mm-1, F(000) = 408。晶体结构用直接法解出,使用全矩阵最小二乘法对原子参数进行修正,最后的偏离因子R = 0.0420,wR = 0.1070。单晶X-射线衍射分析表明平面Ⅰ与平面Ⅱ、平面Ⅲ、平面Ⅳ的夹角分别为102.31、29.24和1.43。平面Ⅱ与平面Ⅲ和平面Ⅳ的夹角分别为73.50和100.91,平面Ⅲ和平面Ⅳ的夹角为27.81, 另外晶体中还存在分子间氢键。     

Convenient synthesis of spiro[indoline-3,4'-pyrano[2,3-c]pyrazole] and spiro[acenaphthyl-3,4'-pyrano[2,3-c]pyrazoles] via fourcomponent reaction

The base promoted four-component reaction of hydrated hydrazine, dimethyl acetylenedicarboxylate, isatines and malononitrile (ethyl cycanoacetate) in ethanol afforded polysubstituted spiro[indoline-3,4‘-pyrano[2,3-c]pyrazoles] and spiro[acenaphthyl-3,4-pyrano[2,3-c]pyrazoles]