共查询到20条相似文献,搜索用时 15 毫秒
1.
A. M. Kamal El-Dean M. S. A. El-Gaby A. M. Gaber H. A. Eyada A. S. N. Al-Kamali 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):413-424
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. 相似文献
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A new series of fused polyheterocyclic aromatic compounds, 7-alkoxybezopyrano[2,3-c]pyrazol-3-one (C- n BPP), were synthesised and characterised by infrared, 1H-nuclear magnetic resonance (NMR), 13C-NMR and two-dimensional 1H-13C cosy spectra. Their phase transition behaviour was investigated by differential scanning calorimetry and polarising optical microscopy. All of these compounds showed enantiotropic mesophases with temperature domains of 12–60°C and 22–69°C on heating and cooling processes for a carbon number of the alkoxy chain from 2 to 10. The effect of the length of the alkoxy chain on the mesomorphic properties was discussed. Comparison of C- n BPP and several kinds of coumarin derivatives indicated that the intermolecular hydrogen bonding acted as the driving force of the mesophase formation. 相似文献
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Yuliya E. Ryzhkova Michail N. Elinson Oleg I. Maslov Artem N. Fakhrutdinov 《Molecules (Basel, Switzerland)》2021,26(22)
Dimethyl sulfoxide is a widely used solvent in organic synthesis and in the pharmaceutical industry because of its low cost, stability, and low toxicity. Multicomponent reactions are an advanced approach that has become an efficient, economical, and eco-friendly substitute for the conventional sequential multi-step synthesis of various biologically active compounds. This approach was adopted for the synthesis of previously unknown 2-(2,4-diamino-3-cyano-5H-chromeno[2,3-b]pyridin-5-yl)malonic acids via transformation of salicylaldehydes, malononitrile dimer, and malonic acid. It was shown that the use of DMSO at room temperature makes it possible to synthesize previously unavailable compounds. The investigation of the reaction mechanism using 1H-NMR monitoring made it possible to confirm the proposed mechanism of the transformation. The structure of synthesized 5H-chromeno[2,3-b]pyridines was confirmed by 2D-NMR spectroscopy. 相似文献
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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. 相似文献
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Afshin Yazdani-Elah-Abadi Malek-Taher Maghsoodlou Razieh Mohebat Reza Heydari 《中国化学快报》2017,28(2):446-452
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. 相似文献
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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. 相似文献
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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. 相似文献
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Ahmed S. N. Al-Kamali 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1812-1824
The alkylation of 4-cyano-5,6-dimethylpyridazin-3(2H)-thione 3 with some halo compounds gave the S-alkylated products 4a–c , which upon treatment with ethanolic sodium ethoxide afforded the cyclized thienopyridazines 5a–c as products. Pyridazothienotriazines 6a–c were prepared by the treatment of compounds 5a–c with nitrous acid, while their reaction with triethyl orthoformate and with carbon disulfide gave the corresponding pyrimidothienopyridazines 7a–c , and 8a–c , respectively. S-alkylated products 9a–o were obtained by the reaction of 8a–c with some halo compounds. 相似文献
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A highly efficient synthesis of 4H-pyrano[2,3-c]pyrazoles has been completed using four-component cyclocondensation of hydrazine monohydrate/phenyl hydrazine, ethyl acetoacetate, aldehydes, and malononitrile in the presence of L-proline and room-temperature ionic liquids. 相似文献
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Jeffrey T. Kuethe 《Tetrahedron》2019,75(34):130446
A strategy for the efficient and rapid one-pot synthesis of 2-aryl-2,3-dihydrofuro[3,2-b], [3,2-c], and [2,3-b]pyridines from readily available o-nitropicolines and aromatic aldehydes is described. The key transformation involves reaction of o-nitropicolines with aromatic aldehydes in the presence of TBAF and Hünig's base giving rise to functionalized products having molecular complexity suitable for further manipulation. 相似文献
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An efficient, simple, and environmentally friendly synthesis of a series of chromeno[2,3-d]pyrimidine-trione derivatives has been accomplished via the three-component reaction of a barbituric acid, dimedone/cyclohexane-1,3-dione, and aromatic aldehydes using Sc(OTf)3 as a recyclable catalyst under solvent-free condition. This method exploits the use of Sc(OTf)3 as a Lewis acid catalyst in organic synthesis and offers many rewards such as excellent product yield and easy work-up procedure. Harmless reaction conditions, as well as the absence of side-products, are another green aspects of this protocol. 相似文献
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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. 相似文献
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Fatma El-Mariah 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2795-2806
Thieno[2,3-c]pyridazine 2 was selected as the starting material for the synthesis of some novel 5-arylidene amino and 5-thiazolidine derivatives. The structures of the synthesized compounds were elucidated by elemental analyses and spectral data. The antimicrobial and antifungal activities of the newly synthesized products were measured against some microorganisms. 相似文献
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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. 相似文献
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Olga Ya. Shyyka Roman L. Martyak Mykola A. Tupychak Nazariy T. Pokhodylo Mykola D. Obushak 《合成通讯》2017,47(24):2399-2405
Convenient two-step procedure for the synthesis of fused chromenone derivatives was developed. Reduction of the obtained in the Meerwein arylation reaction aryl- and thienylquinones allowed to construct 6H-benzo[c]chromene-6-ones and 4H-thieno[2,3-c]chromen-4-one in a more cost- and time-effective manner in comparison with already known methods. The obtained products have provided a new entry to chromenone derivatives. 相似文献
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SONGHong-rui WANGFei LIJian ZHANGShou-fang 《高等学校化学研究》2005,21(4):460-462
The three title compounds were prepared from 2-phenylaminomethyl-3H-1,2-dihydro-l-pyrrolizinols via an intramolecular Friedel-Crafts reaction. 2-Phenylaminomethyl-3H-1,2-dihydro-1-pyrrolizinols were prepared from 2-phenyl-aminomethyl-3H-1,2-dihydro-1-pyrrolizinones via reduction. The heterocyclic ring system of pyrrolizino[2,1-c] quinoline has not been found in literature. 相似文献
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Ali Deeb Wael Shehta 《Phosphorus, sulfur, and silicon and the related elements》2017,192(12):1234-1246
The synthesis and application of ethyl 5-aminothieno[2,3-c]pyridazine-6-carboxylates as building blocks for the synthesis of polyfunctionalized heterocyclic compounds are reviewed. 相似文献
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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. 相似文献