Heterocycles Derived from 5‐(2‐Aminothiazol‐4‐yl)‐8‐hydroxyquinoline: Synthesis and Antimicrobial Activity

5‐(2‐Aminothiazol‐4‐yl)‐8‐hydroxyquinoline 2 has been synthesized by treating thiourea with 5‐chloroacetyl‐8‐hydroxyquinoline 1 . The amine 2 was treated with aromatic aldehydes to furnish schiff bases 6a‐c which on treatment with phenyl isothiocyanate gave the corresponding thiazolo‐s‐triazines 7a‐c . Reaction of 2 with phenyl isothiocyanate gave the corresponding aminocarbothiamide derivative 8 which on reaction with malonic acid in acetyl chloride afforded thiobarbituric acid derivative 9 . Coupling of 9 with diazonium salt gave the phenyl hydrazono derivative 10 . However, reaction of 2 with carbon disulphide and methyl iodide afforded dithiocarbamidate 12 which on treatment with ethylenediamine, o‐aminophenol and/or phenylenediamine gave the aminoazolo derivatives 13–15 , respectively. Other substituted fused thiazolopyrimidines 16–20 have been also prepared by the reaction of 2 with some selected dicarbonyl reagents. The characterisation of synthesized compounds has been done on the basis of elemental analysis, IR, ¹H‐NMR and mass spectral data. All the newly synthesized compounds have been screened for their antimicrobial activities.     

Synthesis and Characterization of 5‐Cyanotetrazolide‐Based Ionic Liquids

New salts based on imidazolium, pyrrolidinium, phosphonium, guanidinium, and ammonium cations together with the 5‐cyanotetrazolide anion [C₂N₅]^? are reported. Depending on the nature of cation–anion interactions, characterized by XRD, the ionic liquids (ILs) have a low viscosity and are liquid at room temperature or have higher melting temperatures. Thermogravimetric analysis, cyclic voltammetry, viscosimetry, and impedance spectroscopy display a thermal stability up to 230 °C, an electrochemical window of 4.5 V, a viscosity of 25 mPa s at 20 °C, and an ionic conductivity of 5.4 mS cm^?1 at 20 °C for the IL 1‐butyl‐1‐methylpyrrolidinium 5‐cyanotetrazolide [BMPyr][C₂N₅]. On the basis of these results, the synthesized compounds are promising electrolytes for lithium‐ion batteries.     

Synthesis and Characterization of SnO2 One-dimensional Nanostructures

Single-crystalline SnO2 nanowires have been successfully prepared in large scale on Au-coated silicon substrate by heating the mixture of self-made high-purity SnO2 powders and graphite powders at 900℃. Besides the line type nanowires some more features were observed. The products were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and Raman spectrum techniques. The results indicate that the tin dioxide nanowires have a rutile structure with diameters ranging from 30 to 120 nm and lengths up to several tens of micrometers. The possible mechanism of the growth and reaction for the nanowires was also discussed.     

One‐Pot Synthesis of 3‐Cyano‐2‐pyridones

A versatile synthesis of 3‐cyano‐2‐pyridones via a one‐pot, four‐component condensation of ethyl cyanoacetate, ketones, aldehydes, and ammonium acetate under very mild conditions has been developed. This method provides rapid access to this type of valuable heterocyclic compounds from readily available materials in a single operation.     

One‐Pot Catalytic Enantioselective Synthesis of 2‐Pyrazolines

A scalable, one‐pot, enantioselective catalytic synthesis of 2‐pyrazolines from beta‐substituted enones and hydrazines is described. Pivoting on a two‐stage catalytic Michael addition/condensation strategy, the use of an aldehyde to generate a suitable hydrazone derivative of the hydrazine was found to be key for curtailing background reactivity and tuning the catalyst‐controlled enantioselectivity. The new synthetic method is easy to perform, uses a new and readily prepared cinchona‐derived bifunctional catalyst, is broad in scope, and tolerates a range of functionalities with high enantioselectivity (up to >99:1 e.r.). The significant scalability of this methodology was demonstrated with the synthesis of more than 80 grams of a pyrazoline product with 89 % catalyst recovery.     

2‐(2′‐Pyridyl)‐4,6‐diphenylphosphinine versus 2‐(2′‐Pyridyl)‐4,6‐diphenylpyridine: Synthesis,Characterization, and Reactivity of Cationic RhIII and IrIII Complexes Based on Aromatic Phosphorus Heterocycles

The bidentate P,N hybrid ligand 1 allows access for the first time to novel cationic phosphinine‐based Rh^III and Ir^III complexes, broadening significantly the scope of low‐coordinate aromatic phosphorus heterocycles for potential applications. The coordination chemistry of 1 towards Rh^III and Ir^III was investigated and compared with the analogous 2,2′‐bipyridine derivative, 2‐(2′‐pyridyl)‐4,6‐diphenylpyridine ( 2 ), which showed significant differences. The molecular structures of [RhCl(Cp*)( 1 )]Cl and [IrCl(Cp*)( 1 )]Cl (Cp*=pentamethylcyclopentadienyl) were determined by means of X‐ray diffraction and confirm the mononuclear nature of the λ³‐phosphinine–Rh^III and Ir^III complexes. In contrast, a different reactivity and coordination behavior was found for the nitrogen analogue 2 , especially towards Rh^III as a bimetallic ion pair [RhCl(Cp*)( 2 )]⁺[RhCl₃(Cp*)]^? is formed rather than a mononuclear coordination compound. [RhCl(Cp*)( 1 )]Cl and [IrCl(Cp*)( 1 )]Cl react with water regio‐ and diastereoselectively at the external P?C double bond, leading exclusively to the anti‐addition products [MCl(Cp*)( 1 H ? OH)]Cl as confirmed by X‐ray crystal‐structure determination.     

One—dimesional Infinite Chain Organotin Compounds： Synthesis and structural Characterization of Triphenyltin Thiazole—2—carboxylate and Triphenyltin 3—Pyridinylcarboxylate

Triphenyitin thiazole-2-carboxylate(1) and triphenyltin 3-pyridinylcar boxylate(2) were synthesized by the reaction of sodium thiazole-2-carboxylate or sodium 3-pyridinylcarboxylate with the triphenyltin chloride and their crystal structures were determined by single crystal X-ray diffraction analysis.In the structure of 1, the tin atom is five-coordinated in a distorted trigonal bipyramidal structure.Due to the presence of a close intermolecular Sn…S interaction distance of 0.3666nm,the structre can be described as a weakly-bridged on-dimensional chain compound.In the structure of 2,the tin atom is five-coordinated with bridging 3-pyridinylcarboxylate ligands N atom and resulting structure is one-dimensional chain compound.     

Old Selenium Heterocycles Revisited: Synthesis,Spectroscopic, and Structural Characterization of N‐Acyl‐1,3‐selenazol‐2(3H)‐imines and 5‐Acyl‐1,3‐selenazol‐2‐amines from Acylselenourea Derivatives

A series of five‐membered selenium heterocycles was prepared from the reaction of various selenoureas and phenacyl bromides. In the case of 1‐acyl‐3‐arylselenoureas N‐acyl‐1,3‐selenazol‐2(3H)‐imines are formed, whereas the analogous reaction with 3,3‐disubstituted 1‐acylselenoureas affords 5‐acyl‐1,3‐selenazol‐2‐amines. The compounds were characterized by NMR spectroscopy and mass spectrometry. In addition, the proposed structures were unambiguously confirmed by X‐ray diffraction studies.     

One‐pot Three‐component Synthesis of Furan‐based Heterocycles from Benzyl Halides

An efficient and a novel approach for the synthesis of furochromene and furopyran scaffolds are described. Benzyl halides undergo oxidation in Kornblum conditions to give the corresponding aldehydes, which in turn undergo [4 + 1] cycloaddition reaction with isocyanide to afford the corresponding furan derivatives. The significant attraction of this protocol is simple procedure, mild reaction condition, and good yield.     

One‐Pot Synthesis of 2‐Arylbenzoxazoles Promoted by Heteropolyacids

Benzoxazole derivatives were obtained in high yields with excellent purity from the condensation of 2‐aminophenol with benzaldehydes and benzoic acids in the presence of a catalytic amount of heteropolyacids (HPAs).     

Selenium‐Containing Heterocycles from Isoselenocyanates: Synthesis of 1H‐5‐Selena‐1,3,6‐triazaaceanthrylene Derivatives

The reaction of aryl isoselenocyanates 8 with methyl 3‐amino‐4‐chloro‐1‐ethylpyrrolo[3,2‐c]quinoline‐2‐carboxylate ( 6 ) in boiling pyridine leads to tetracyclic selenaheterocycles of type 9 in high yield (Scheme 3). A reaction mechanism via an intermediate selenoureido derivative A and cyclization via nucleophilic substitution of Cl by Se is proposed (Schemes 3 and 5). The reaction of 6 with 4‐bromophenyl isothiocyanate yields the analogous thiaheterocycle 12 (Scheme 4). The molecular structures of 9c and 12 have been established by X‐ray crystallography.     

An Efficient One‐pot Synthesis of 2‐Amino‐5‐arylidenethiazol‐4‐ones Catalyzed by MgO Nanoparticles

A mild and efficient protocol for the synthesis of 2‐amino‐5‐arylidene‐1,3‐thiazol‐4(5H)‐ones is reported by three component reaction of aldehydes, rhodanine and secondary amines in the presence of magnesium oxide nanoparticles as heterogeneous nanocatalyst in good yields and short reaction times.     

One‐Pot Multicomponent Synthesis of β‐Amino Amides

Multicomponent reactions are excellent tools for rapid generation of small molecules with broad chemical diversity and molecular complexity. Herein, a novel one‐pot multicomponent synthesis of β‐amino amides from aldehydes, anilines, carboxylic acids and ynamides has been successfully developed. This process is practical and efficient to unravel synthetic utility and scalability. Moreover, an isotope labeling reaction was conducted to elucidate a plausible reaction mechanism.     

Synthesis of Novel Heterocycles Derived from 4‐Arylmethylene‐2‐phenyl‐1,3‐oxazole‐5(4H)‐ones

The acid hydrazide derivatives 2 were converted into pyrazolone, triazinone, and schiff bases. However, the reaction of Schiff base 12 with malononitrile or thioglycolic acid gives the pyrazolotriazinone or thiazolidinone derivative, respectively. The structures of the newly synthesized compounds were established on the basis of IR, ¹H‐NMR, mass spectral data, and elemental analyses. The antimicrobial activities of the synthesized compounds were examined against two types of bacteria and two types of fungi. Some of the tested compounds showed promising activities.     

One‐pot Synthesis of a 3,4,5‐Triaryltriazole from the Subsitituted 1,3,4‐Oxadiazole: Crystal Structures Characterization

Two heterocyclic compounds, 2‐(p‐bromophenyl)‐5‐(2‐pyridyl)‐1,3,4‐oxadiazole ( 1 ) and 3‐(p‐bromophenyl)‐4‐phenyl‐5‐(2‐pyridyl)‐1,2,4‐triazole ( 2 ) were successfully synthesized and characterized by UV–vis, FTIR, ¹H NMR, ESI‐MS spectra, elemental analysis, and single crystal X‐ray crystallography. The structural analysis indicates that 1 is almost a planar molecule but 2 not. The crystal structure of 1 is stabilized by two kinds of intermolecular π–π interactions and two types of intermolecular C–H···N hydrogen bonds, whereas 2 by three kinds of C–H···π interactions and three types of intermolecular C–H···N hydrogen bonds. Additional, 2 can be prepared directly from 1 in an aniline solution at 190°C in a yield of 70%.     

One‐Pot Synthesis of 1,3,5‐Triarylpyrazoles

A series of novel 1,3,5‐triarylpyrazoles 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l , 3m , 3n , 3o , 3p , 3q , 3r , 3s , 3t , 3u , 3v , 3w , 3x were synthesized from flavanones, arylhydrazines, and trimethyl phosphate in an one‐pot procedure. Facile reaction process, easy after‐reaction workshop, and good yields are the distinct characteristics of the developed protocol. The target compounds were characterized by element analysis, infrared ray (IR), ¹H NMR spectra, and electrospray ionization‐mass spectrometry. The structure of representative compound 3h (C₂₃H₂₀N₂O₃, M_r = 372.42) was further confirmed by X‐ray diffraction. It crystallizes in monoclinic, space group P 2₁/c, a = 8.9720(5), b = 24.5523(13), c = 8.9687(6) Å, α = 90.0000, β = 102.6417(17), γ = 90.0000°, V = 1927.76(20) ų, Z = 4, μ(MoKα) = 0.086, F(000) = 784, D_c = 1.283 g/cm³, the final R = 0.0349 and wR = 0.0844 for 1668 observed reflections (I > 2σ(I))     

One‐Step Synthesis of 1‐(4,5‐Diphenylpyrimidin‐2‐yl)thiourea

A simple and straightforward methodology toward the synthesis of novel 1‐(4,5‐diphenylpyrimidin‐2‐yl)thiourea has been developed by a one‐step reaction of isoflavones with amidinothiourea. A series of 16 new compounds was synthesized. All compounds were characterized by FT‐IR, NMR, and elemental analysis. The structure of a typical compound was established by X‐ray diffraction. A variety of substrates can participate in the process with good yields and high purities, making this methodology suitable for library synthesis in drug discovery.