Synthesis of 4-Acyl-2-amino-6-(arylsulfanyl)pyridine-3,5-dicarbonitriles

Russian Journal of Organic Chemistry - The reaction of 4-acyl-2-amino-6-chloropyridine-3,5-dicarbonitriles with aromatic thiols in 1,4-dioxane in the presence of triethylamine led to the formation...     

Crystal structures and fluorescence properties of two architecture-correlated Zn(II)/Cd(II) MOFs constructed from an unprecedented tri-triazole ligand

By employing an unprecedented tri-triazole ligand, 4-amino-3,5-bis-(1H-1,2,4-triazole)-1,2,4-triazole (H₂L), two Zn(II)/Cd(II) metal-organic frameworks (MOFs), [ZnL]·3H₂O (1) and [CdL]·H₂O (2), were successfully synthesized and characterized. In the two complexes, M(II) centers are chelated and bridged by L bridges to form a one-dimensional (1-D) 4₁ helical chain in 1 with high-symmetry Pbca, and a 2₁ helical chain in 2 with lower symmetry P2₁/n, respectively. The two chains are further linked by L into two structure-correlated three-dimensional (3-D) architectures. PXRD and TG analysis confirmed the phase purity and stability of 1 and 2. The solid-state fluorescence properties of the prepared MOF revealed a maximum emission at 382?nm and 393?nm (λ_ex = 330?nm), ascribing to the intra-ligand transitions. Interestingly, an additional strong emission peak at 516?nm can be observed in 1 (below 400?°C), while the emission was silenced in 2. The additional emission band may be attributed to the subtle difference of architectural features and coordination configurations between in 1 and 2.     

Improved preparation of alkyl 2-(3-indolyl)-3-nitroalkanoates under fully heterogeneous conditions: stereoselective synthesis of alkyl (E)-2-(3-indolyl)-2-alkenoates

Ethyl 3-nitro-2-alkenoates can be generated starting from nitroalkanes and ethyl 2-oxoacetate under heterogeneous conditions that minimize work-up procedures, avoid any purification step and direct manipulation of the nitroalkene system. Reaction of ethyl 3-nitro-2-alkenoates, formed in situ from their acetoxy precursors, with indoles in the presence of basic alumina affords ethyl 2-(3-indolyl)-3-nitroalkanoates that are central intermediates for the preparation of tryptamines and carboline alkaloids. A base promoted elimination of nitrous acid from these nitroindolyl derivatives readily produces ethyl 2-(3-indolyl)-2-alkenoates with high E stereoselectivity. The latter compounds can be used as Michael acceptors in intra- and intermolecular reactions with nucleophilic reagents.     

Isolation of hemoglobin with metal–organic frameworks Y(BTC)(H_2O)_6

The hierarchical metal-organic frameworks(MOFs),such as Y(BTC)(H_2O)_6,are prepared with yttrium nitrate and benzene-1,3,5-tricarboxylic acid at room temperature.The product is characterized by Fourier transform infrared(FT-IR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and thermogravimetric analysis(TGA).The Y(BTC)(H_2O)_6 particles are sufficiently rigid for performing solid phase extraction and they exhibit favorable selectivity toward the adsorption of hemoglobin.The adsorption behavior of hemoglobin onto the Y(BTC)(H_2O)_6 fits the Langmuir adsorption model with a theoretical adsorption capacity of 555.6 mg g 1.An adsorption efficiency of 87.7%for 100μg mL 1hemoglobin in 1 mL sample solution(at pH 6.0)is achieved with 0.40 mg Y(BTC)(H20)6.77.3%of the retained hemoglobin is readily recovered using a 0.5%(m/v)SDS solution as the stripping reagent.Circular dichroism spectra indicated that the conformation of hemoglobin is maintained during the adsorption-desorption process.The MOFs material is applied for the isolation of hemoglobin from human blood and the purity of the obtained hemoglobin is further verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE).     

CaO nanoparticles incorporated metal organic framework (NH2-MIL-101) for Knoevenagel condensation reaction

Porous materials based on NH₂-MIL-101(Cr) MOF and their hierarchical acid-base composite with non-precious CaO was successfully prepared using a one-pot scalable hydrothermal approach. The composites were characterized by XRD, FTIR, UV–vis, ¹HNMR, TGA, N₂ adsorption–desorption isotherms, HRTEM and FESEM. The quantitative assessment of the basic sites was performed by benzoic acid titration. The results reveal that there is no remarkable structural alterations in the NH₂-MIL-101(Cr) after incorporation of CaO. Raising the CaO content boosted the strength of and content of Lewis basic sites from 0.31 to 1.34 mmol g^?1 due to the incorporation with CaO (0.04). Knoevenagel condensation reactions were performed as the probe reactions over the CaO/NH₂-MIL-101(Cr) catalysts. Both basic and acidic sites potentially boosted the reaction. Pure NH₂-MIL-101(Cr) display the catalytic conversion in the reaction (11%) which could be attributed weak basic sites on the NH₂-MIL-101(Cr) framework. However, the conversion (%) was potentially increased over NH₂-MIL-101(Cr) loaded with various content of CaO. The highest performance of (99%) conversion was achieved for (0.04) CaO/NH₂-MIL-101(Cr) catalyst. Exceptional conversion above 90% have been obtained for benzaldehyde derivatives both withdrawing and donating electron moieties. The composites can be recycled in four runs with a very small loss in performance. Furthermore, the composites produced tend to be feasible for various catalytic processes, exploring new avenues to produce of novel inorganic and organic composite materials as heterogeneous catalysts.     

One-pot synthesis of 2-amino-3-cyanopyridine derivatives under solvent-free conditions

A series of 2-amino-3-cyanopyridines were obtained from aryl aldehydes, substituted acetophenones, malononitrile and ammonium acetate in good to excellent yields by proceeding through a simple, mild and efficient procedure utilizing N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide [TBBDA] and poly(N-bromo-N-ethylbenzene-1,3-disulfonamide) [PBBS] as catalysts.     

Ligand controlled structure of cadmium(II) metal-organic frameworks for fluorescence sensing of Fe3+ ion and nitroaromatic compounds

2-Fold interpenetrating 3D framework for selective adsorption of CO₂ over CH₄ and fluorescence detection of Fe³⁺ ions and nitroaromatic compounds through fluorescence quenching.     

Microwave assisted synthesis of hydroxychromenes using imidazole-functionalized silica nanoparticles as a catalyst under solvent-free conditions

A microwave-assisted reaction of various salicylaldehydes with dialkyl acetylenedicarboxylates mediated by imidazole-functionalized silica nanoparticles is successfully and rapidly achieved to afford the corresponding hydroxychromenes in high to excellent yields under solvent-free conditions.     

A Doubly Interpenetrated Cu(II)-based Metal-Organic Framework as a Heterogeneous Catalyst for the ipso-Hydroxylation of Arylboronic Acids

A doubly interpenetrated Cu(II)-organic framework with formula [{Cu₂( L )₂(4,4′-bpdc)₂(H₂O)₂} ⋅ 8H₂O ⋅ CH₃OH]_α ( 1 ) (where, L =N², N⁶-di(pyridin-4-yl)naphthalene-2,6-dicarboxamide and 4,4′-bpdc=[1,1′-biphenyl]-4,4′-dicarboxylate ion) has been synthesized and characterized with the help of several spectroscopic and analytical techniques including single crystal X-ray analysis. A single crystal X-ray analysis reveals that 1 exhibit interpenetrated two-dimensional sheet-like structure containing elongated channels of cross-section 11.09×31.22 Ų along the a-axis. Finally, 1 has been exploited as a heterogeneous catalyst for the ipso-hydroxylation of arylboronic acids yielding up to 99 % of the respective phenolic product. Importantly, the catalyst can be reused for five successive cycles without having a significant loss in its catalytic efficiency.     

无溶剂条件下三聚氰胺-Br_3催化一锅法合成1-氨基烷基-2-萘酚(英文)

A facile and efficient method has been developed for the synthesis of 1-amidoalkyl-2-naphthols via the one-pot multi-component condensation of 2-naphthol with aromatic aldehydes and acetamide or thioacetamide in the presence of melamine-Br3 under solvent-free conditions. There are several advantages to this reaction, including high yields, short reaction time, and high catalytic efficiency.     

Acetylation of alcohols and phenols under solvent-free conditions using copper zirconium phosphate

Copper zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetyla‐tion of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under sol...     

Rational design and syntheses of 0-D, 1-D, and 2-D metal-organic frameworks (MOFs) from ferrocenedicarboxylate tetrametallic macrocyclic building units and subsidiary ligands

We have designed and synthesized three new metal-1,1′-ferrocenedicarboxylate complexes containing tetrametallic macrocyclic building units, namely, [Cd₂(η²-O₂CFcCO₂-η²)₂(phen)₂(H₂O)₂] · 4CH₃OH (1) (Fc = (η⁵-C₅H₄)Fe(C₅H₄-η⁵), phen = 1,10-phenanthroline), {[Cd(η²-O₂CFcCO₂)(pebbm)(H₂O)] · 2H₂O}_n (2) (pebbm = 1,1′-(1,5-pentanediyl)bis-1H-benzimidazole) and {[Cd(η²-O₂CFcCO₂-η²)(prbbm)(H₂O)] · 3H₂O}_n (3) (prbbm = 1,1′-(1,3-propanediyl)bis-1H-benzimidazole). Compound 1 is a 0-D discrete tetrametallic macrocyclic framework. Compound 2 features an infinite 1-D ribbon of rings structure constructed by the subsidiary ligands pebbm connecting tetrametallic macrocyclic building units. For 3, its tetrametallic macrocyclic building units are linked by the subsidiary ligands prbbm to form a 2-D network structure. The structural features of these complexes indicate that the ferrocenedicarboxylate tetrametallic macrocycle can be used as a successful molecular building unit and the shapes and conformational flexibility of subsidiary ligands play a crucial role in the manipulation of the configuration of the resultant MOFs. Their fluorescence spectra in solid state at room temperature suggest that the fluorescence emissions of 1-3 are ruled by 1,1′-ferrocenedicarboxylate ligand.     

One-pot synthesis of dihydropyrimidiones catalyzed by strontium(II) triflate under solvent-free conditions

A simple, efficient and practical procedure for the Biginelli reaction using strontium(II) triflate [Sr(OTf)₂] as a novel catalyst is described under solvent-free conditions in high yields. The catalyst exhibited remarkable reactivity and it is reusable. Some of dihydropyrimidiones showed strong pesticidal activity.     

An isocyanide based multi-component reaction under catalyst- and solvent-free conditions for the synthesis of unsymmetrical thioureas

A new and efficient method for the synthesis of thiourea derivatives by a sequential one-pot, three-component reaction between aromatic isocyanides, amines, and 1,2-di-tert-butyldisulfane (DTBS) was developed and 27 different examples were synthesized in good to excellent yields. DTBS was identified as an effective sulfur surrogate without the use of both catalysts and solvents. This protocol does not employ any transition metal catalyst or special experimental setup.     

Novel ZnCl2-catalyzed one-pot multicomponent synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines

ZnCl₂-catalyzed one-pot multicomponent synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines under microwave heating and conventional heating is described.     

Release behavior,kinetic and antimicrobial study of nalidixic acid from [Zn2(bdc)2(dabco)] metal-organic frameworks

In the present study, a hydrothermal method was developed to prepare nalidixic acid-loaded [Zn₂(bdc)₂(dabco)] metal–organic frameworks. The self-assembly of primary building blocks was used for synthesis of [Zn₂(bdc)₂(dabco)] at room temperature. The zinc metal ion was used as a connector, 1,4-benzenedicarboxylate (bdc) as a chelating ligand, and 1,4-diazabicyclo[2.2.2]octane (dabco) as a bridging ligand. The metal organic frameworks were used as the carriers for drug delivery system, where it could entrap nalidixic acid as a model drug. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), ultraviolet-visible spectroscopy (UV–vis), BET nitrogen adsorption–desorption method, and scanning electron microscopy (SEM) were used for characterization of samples. The drug release was also monitored, and 96 and 62% of the loaded drug were released over 120 h at pH values of 5.0 and 7.4, respectively. The antimicrobial activities of [Zn₂(bdc)₂(dabco)] and nalidixic acid-loaded [Zn₂(bdc)₂(dabco)] were tested against Gram-positive and Gram-negative species. The results revealed that this nanoscale metal organic framework may be regarded as a simple and stable platform for drug release in the treatment of infectious diseases.     

Tungstate sulfuric acid as an efficient catalyst for the synthesis of benzoxazoles and benzothiazoles under solvent-free conditions

Tungstate sulfuric acid (TSA) has been found to be an efficient and reusable catalyst for the synthesis of benzoxazole and benzothiazole derivatives via reactions of orthoesters with o-aminophenols or o-aminothiophenols in high yields.     

Construction of three new metal-organic frameworks with distinct SBUs: trinuclear {Cd3(COO)6} clusters,inorganic -Cd-O-Cd- chains,and heterometallic trinuclear {Cd2Ba(COO)4} clusters

Three metal-organic frameworks (MOFs), [Cd₃(OABDC)₂(e-urea)₄]_n (1), [Cd₃(OABDC)₂(H₂O)₅)]_n (2) and [Cd₂Ba(OABDC)₂(H₂O)₇]_n (3) (H₃OABDC = 5-oxyacetate isophthalic acid, e-urea = 2-imidazolidinone), were prepared using H₃OABDC and metal salts. Single-crystal X-ray diffraction analyses reveal that 1 features a 2-D layered structure constructed from trinuclear {Cd₃(COO)₆} SBUs and represents a (3,6)-connected kgd topology. Compounds 2 and 3 are 3-D inorganic–organic hybrid frameworks; 2 employs infinite inorganic –Cd–O–Cd– chains as SBUs, whereas (3,6)-connected ant-type 3 employs heterometallic trinuclear {Cd₂Ba(COO)₄} clusters as SBUs. The structures of these three compounds indicate that the SBUs play an important role in the construction of MOFs. Moreover, the thermal stabilities and solid-state photoluminescent properties of these three compounds have also been investigated.     

Ammonium chloride-catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent-free conditions

Ammonium chloride as a very inexpensive and readily available reagent, and efficiently catalyzes one-pot, three component, Biginelli condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions to afford the corresponding 3,4-dihydropyrimidin-2-(1H)-ones in high yields at 100°C.     

Copper(II) complexes of 2-amino-5-chloro-3-fluoropyridine: syntheses and magnetic properties of (3,5-FCAP)2CuX2 and (3,5-FCAPH)2CuX4

Using 2-amino-5-chloro-3-fluoropyridine, two new copper halide coordination complexes and two new salts have been synthesized: [(3,5-FCAP)₂CuCl₂] (1), [(3,5-FCAP)₂CuBr₂](2), (3,5-FCAPH)₂[CuCl₄] (3) and (3,5-FCAPH)₂[CuBr₄] (4) [3,5-FCAP?=?2-amino-5-chloro-3-fluoropyridine; 3,5-FCAPH?=?2-amino-5-chloro-3-fluoropyridinium]. These complexes have been analyzed through single-crystal X-ray diffraction and temperature-dependent magnetic susceptibility. Compounds 1 and 2 crystallize in the triclinic space group P-1, while 3 and 4 crystallize in the monoclinic space group P2₁/c. All structures were distinct, with 1 giving a bihalide bridged chain, 2 yielding a halide bridged dimer, 3 forming a two-halide bridged chain via short Cl???Cl contacts, and 4 producing a rectangular sheet via short Br???Br contacts. All four compounds exhibit anti-ferromagnetic interactions and were fit to linear chain (1 and 3), dimer (2), and rectangular 2-D sheet (4) models. The resulting J/k_B values are ?3.4(1), ?31.3(8), ?0.9(1), and ?9.46(6)?K with an α value (α?=?J?/J) of 0.06(2), respectively.