Synthesis and Anticancer Activity of New Substituted Pyrazoles and Their Derived 1,2,4‐Triazoles and Sugar Derivatives

New substituted pyrazole, thiazole, and 1,2,4‐triazole derivatives were synthesized. The sugar hydrazones, their acetylated derivatives as well as their derived acyclic C‐nucleoside analogs, and the thioglycosides of the 1,2,4‐traizole derivatives were also prepared. The antitumor activity of some of the synthesized compounds were studied, and a number of the tested compounds showed significant activities.     

General and environmentally friendly synthesis of heterocyclic multidentate molecules based on microwave-assisted heating protocol

An efficient microwave heating methodology for the synthesis of heterocyclic multidentate molecules is reported. Each compound was obtained with high yield and purity in a few minutes from easily available starting materials such as amines, heteroaldehydes and N-hydroxymethyl pyrazoles or triazoles. In addition, this approach allows synthesis without any solvent or organic and inorganic by-products.     

含吡唑环的1,2,4-三唑希夫碱类衍生物的合成及生物活性

以自制的4-氨基-4,5-二氢-3-[(3,5-二甲基吡唑-1-基)甲基]-1,2,4-三唑-5-硫酮衍生物为中间体, 与取代苯甲醛反应合成了一系列新型含吡唑环的1,2,4-三唑希夫碱衍生物. 通过红外光谱、 核磁共振波谱、 高分辨质谱、 元素分析及X射线单晶衍射对目标化合物进行了结构表征, 并初步测试了其生物活性. 结果表明, 大部分化合物表现出较好的抑菌活性, 其中化合物G9, G10和G15的抑菌效果优于对照药三唑酮.     

A Modified and Practical Synthetic Route to Indazoles and Pyrazoles Using Tungstate Sulfuric Acid

Tungstate sulfuric acid‐catalyzed Knorr reaction have been used as a simple, rapid, atom economic and green method for the synthesis of indazole and pyrazole derivatives based on the condensation of hydrazine derivatives and ß‐dicarbonyl compounds under solvent‐free conditions. It was found that the catalyst could be recovered and reused without significant loss of its activity. The use of this method provides a novel and improved modification of Knorr synthesis in terms of clean reaction profile, use of a safe catalyst and solvent‐free conditions.     

A Scalable Metal-, Azide-, and Halogen-Free Method for the Preparation of Triazoles

A scalable metal-, azide-, and halogen-free method for the synthesis of substituted 1,2,3-triazoles has been developed. The reaction proceeds through a 3-component coupling of α-ketoacetals, tosyl hydrazide, and a primary amine. The reaction shows outstanding functional-group tolerance with respect to both the α-ketoacetal and amine coupling partners, providing access to 4-, 1,4-, 1,5-, and 1,4,5-substituted triazoles in excellent yield. This robust method results in densely functionalised 1,2,3-triazoles that remain challenging to prepare by azide–alkyne cycloaddition (AAC, CuAAC, RuAAC) methods and can be scaled in either batch or flow reactors. Methods for the chemoselective reaction of either aliphatic amines or anilines are also described, revealing some of the potential of this novel and highly versatile transformation.     

A fast and efficient bromination of isoxazoles and pyrazoles by microwave irradiation

A fast and efficient method has been developed for the bromination of isoxazoles and pyrazoles using microwave irradiation. In this method, N-bromosuccinimide was used in different acid solvents according to the reactivity of the substrates to give mono-brominated isoxazoles and pyrazoles in good yields. Trifluoroacetic acid was found to be the best solvent for highly unreactive isoxazoles and pyrazoles.     

1-(取代吡唑-4-甲酰基)吡唑类化合物的合成及生物活性研究

设计合成了25个新型1-取代吡唑甲酰基吡唑系列衍生物,化合物结构经¹HNMR、元素分析、IR和MS确证.生物活性测试结果表明,该类化合物具有一定除草活性,讨论了其结构与活性的关系.     

N-Alkylation of Pyrazoles with Mannich Bases Derived from ortho-Hydroxyacetophenones

The involvement of Mannich bases derived from ortho-hydroxyacetophenones in amine-exchange reactions with pyrazole and methyl- and/or halogen-substituted pyrazoles was studied. The corresponding -(pyrazol-1-yl)ethyl ketones resulted in excellent yield and were characterized by elemental analysis, IR, and ¹H and ¹³C NMR spectroscopy.     

Synthesis,crystal structure and fungicidal activity of 1-(4-chlorophenyl)-2-(5-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-4-phenyl-4H-1,2,4-triazol-3-ylthio)ethanone

A novel bis-heterocyclic compound was synthesized and characterized. The crystal structure of the title compound (C₂₂H₂₀ClN₅OS, Mr = 437.94) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P-1 with a = 8.646 (2), b = 9.148 (3), c = 14.540 (4) Å, α = 94.422 (4), β = 98.500 (4), γ = 102.823 (4)°, V = 1101.8 (5) Å³, Z = 2, F(000) = 312, Dc = 1.320 g/cm³, μ = 0.2900 mm^?1, the final R ₁ = 0.041000 and wR ₂ = 0.1160 for 2675 observed reflections with I > 2σ(I). A total of 5623 reflections were collected, of which 3866 were independent (R _int = 0.019000). The fungicidal activity of title compound was determined, the results showed the title compound displayed moderate fungicidal activity against G. zeae Petch, Phytophthora infestans (Mont.) de Bary, Botryosphaeria berengeriana f. sp. piricola (Nose) koganezawa et Sakuma, Fusarium oxysporum f.sp. cucumerinum, and Cercospora arachidicola.     

A Unified Continuous Flow Assembly‐Line Synthesis of Highly Substituted Pyrazoles and Pyrazolines

A rapid and modular continuous flow synthesis of highly functionalized fluorinated pyrazoles and pyrazolines has been developed. Flowing fluorinated amines through sequential reactor coils mediates diazoalkane formation and [3+2] cycloaddition to generate more than 30 azoles in a telescoped fashion. Pyrazole cores are then sequentially modified through additional reactor modules performing N ‐alkylation and arylation, deprotection, and amidation to install broad molecular diversity in short order. Continuous flow synthesis enables the safe handling of diazoalkanes at elevated temperatures, and the use of aryl alkyne dipolarphiles under catalyst‐free conditions. This assembly‐line synthesis provides a flexible approach for the synthesis of agrochemicals and pharmaceuticals, as demonstrated by a four‐step, telescoped synthesis of measles therapeutic, AS‐136A, in a total residence time of 31.7 min (1.76 g h⁻¹).     

手性臂脱氧胆酸分子裂缝受体的一锅法微波合成

以脱氧胆酸为隔离基,3位构建非手性单元,12位引入手性单元,微波辐射一锅法合成具有不同手性中心和裂穴的新型手性臂分子裂缝受体,结构均经1H NMR、IR、MS及元素分析所确证。     

Syntheses and structures of azol-1-yl derivatives of nitronyl and imino nitroxides

2-(Pyrazol-1-yl)-, 2-(imidazol-1-yl)-, 2-([1,2,4]triazol-1-yl)-, and 2-(benzotriazol-1-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl were prepared by reactions of 2-bromo-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (NIT-Br) with the corresponding sodium azolides. In prepared 2-(azol-1-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyls, the NIT-N_Het bond is readily hydrolyzed. Reduction of imidazole-3-oxide-1-oxyls leads to corresponding 2-(azol-1-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyls, which are much more stable against hydrolysis. The structures of spin-labeled imidazoles, [1,2,4]triazoles and benzotriazoles are confirmed by X-ray analysis, showing that the paramagnetic molecules form packings with motifs from centrosymmetric dimers to topologically linear chains.     

Selenium- and tellurium-based ionic liquids and their use in the synthesis of octahydroacridines

A general and easy method for the synthesis of several selenonium and telluronium salts is described. These compounds are acidic liquids at room temperature and were obtained in excellent yields. Phenyl butyl ethyl selenonium tetrafluoroborate was employed in the hetero-Diels-Alder cyclization of aryl imines derived from citronellal, affording octahydroacridines in good yields.     

Green chemical multi-component one-pot synthesis of fluorinated 2,3-disubstituted quinazolin-4(3H)-ones under solvent-free conditions and their anti-fungal activity

A rapid one-pot solvent-free procedure has been developed for the synthesis of fluorinated 2,3-disubstituted quinazolin-4(3H)-ones by neat three-component cyclocondensation of anthranilic acid, phenyl acetyl chloride and substituted anilines under microwave irradiation. The experimental methodology and microwave conditions described here are well established, allowing significant rate enhancement and good yields compared to conventional reaction conditions. The reaction is generalized for O, M & P substituted anilines to give quinazolin-4(3H)-ones. Synthesized compounds have been screened for their antifungal activity.     

Green chemical multi-component one-pot synthesis of fluorinated 2,3-disubstituted quinazolin-4(3H)-ones under solvent-free conditions and their anti-fungal activity

A rapid one-pot solvent-free procedure has been developed for the synthesis of fluorinated 2,3-disubstituted quinazolin-4(3H)-ones by neat three-component cyclocondensation of anthranilic acid, phenyl acetyl chloride and substituted anilines under microwave irradiation. The experimental methodology and microwave conditions described here are well established, allowing significant rate enhancement and good yields compared to conventional reaction conditions. The reaction is generalized for o-, m- and p-substituted anilines with electron-donating and -withdrawing groups to give quinazolin-4(3H)-ones. Synthesized compounds have been screened for their anti-fungal activity.     

Microwave assisted synthesis of substituted furan-2-carboxaldehydes and their reactions

A series of 5-unsubstituted and 5-substituted furfurylidenes have been prepared, under thermal and non-thermal microwave irradiation methods, via condensation of furfural and its derivatives with some of active methylene compounds. Furthermore, various condensate products from these furfurylidenes, which contain halogen or sulpher atoms, were also prepared. Structural elucidation of the synthesized compounds were determined on the basis of various spectroscopic methods.     

Nano-organocatalyst: magnetically retrievable ferrite-anchored glutathione for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis

Postsynthetic surface modification of magnetic nanoparticles by glutathione imparts desirable chemical functionality and enables the generation of catalytic sites on the surfaces of ensuing organocatalysts. In this article, we discuss the developments, unique activity, and high selectivity of nano-organocatalysts for microwave-assisted Paal-Knorr reaction, aza-Michael addition, and pyrazole synthesis. Their insoluble character coupled with paramagnetic nature enables easy separation of these nano-catalysts from the reaction mixture using external magnet, which eliminates the requirement of catalyst filtration.     

Microwave-assisted preparation of imidazolium-based tetrachloroindate(III) and their application in the tetrahydropyranylation of alcohols

Microwave-assisted preparation of 1-alkyl-3-methylimidazolium tetrachloroindate(III), [Rmim][InCl₄] (R = methyl, ethyl, butyl, hexyl, octyl) and their application as recyclable catalysts for the efficient and eco-friendly protection of alcohols to form tetrahydropyranyl (THP) ethers are described.     

Synthesis and Characterization of Novel Thiosemicarbazones Bearing Sugar Moieties

IntroductionIt is well known that carbohydrates play importantroles in a wide variety of biological processes[1], suchas cell adhesion to the extracellular matrix and cell sig-naling. They can also act as the ligands for growth fac-tors[2,3].Substituted t…