Rigid diol bearing 6‐6‐6 fused ring system derived from naturally occurring myo‐inositol and its polyaddition with diisocyanates

Naturally occurring myo‐inositol was developed into a highly rigid diol by converting its 3,4‐ and 1,6‐vicinal diols in trans configuration into the corresponding butane‐2,3‐diacetals. The resulting diol bearing 6‐6‐6 fused ring system, in which conformational change is strictly suppressed, was combined with diisocyanates to perform polyadditions. The resulting polyurethanes were analyzed by differential scanning calorimetry, and it was found that their glass transition temperatures were much higher than those of the previously reported myo‐inositol‐derived polyurethanes, which were synthesized from a myo‐inositol‐derived diol bearing 5‐6‐5 fused ring system. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3798–3803     

A highly rigid diamine monomer derived from naturally occurring myo‐inositol and its use for polyamide synthesis

A rigid diamine was synthesized from myo‐inositol, a naturally occurring cyclic hexaol, and used as a monomer to synthesize polyamides. myo‐Inositol was treated with 1,1‐dimethoxycyclohexane to yield a bisketal bearing two hydroxyl groups, and from this bisketal, the target diamine was synthesized in three steps: (1) derivation of the diol into the corresponding bistriflate, (2) nucleophilic substitution of the bistriflate with sodium azide yielding a diazide, and (3) reduction of the diazide to the target diamine. The target diamine readily underwent polycondensation with dicarboxylic acid chloride in solution. The resulting polyamides, whose main chain inherited the rigid 5‐6‐5 system from the diamine monomers, have high glass transition temperatures. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3436–3443     

A novel and facile synthesis of 2,3-dihydrofuran derivatives containing trifluoromethyl group

A series of CF₃-containing 2,3-dihydrofuran derivatives were prepared via the reaction of arsonium bromides 1 with β,β-di(trifluoroacetyl)ethylene derivatives 2 in the presence of K₂CO₃, usually in a stereoselective manner with moderate yields. The structures of these compounds were confirmed by ¹H NMR, ¹³C NMR, IR, MS and HRMS as well.     

A novel Friedlander-type synthesis of 3-aryl quinolines from 3-oxo-2,3-diaryl-propionaldehydes

3-Aryl quinolines are readily synthesized by a novel Friedländer-type reaction with 3-oxo-2,3-diaryl-propionaldehydes and 2-amino arylaldehydes. A preliminary mechanism of this novel one pot, two-step synthesis has been explored with the proofs of isolation of the enaminone intermediate and the eliminated benzoic acid in this reaction.     

Chemistry of anthracene-acetylene oligomers: synthesis and enantiomeric resolution of a chiral 1,8-anthrylene-ethynylene cyclic tetramer

To construct a new type of chiral pi-conjugated system, the title anthracene-acetylene oligomer containing two octyl groups at position 10 of 1,2-alternating anthracene groups was synthesized. Each anthracene unit was connected by Sonogashira coupling, and the tetrameric precursor was cyclized by a cross-coupling reaction to form the desired C2-symmetric compound. Its enantiomers were resolved by chiral HPLC with a Chiralcel OD column, and the chiroptical properties were investigated by optical rotation ([alpha]D(23) = -95 and +91) and circular dichroism (CD) measurements. The structural and spectroscopic features of this oligomer were discussed in terms of the molecular symmetry and the dynamic behavior of the macrocyclic framework.     

A green approach to the synthesis of 2,3‐diaminophenazine using a photocatalytic system of CdFe2O4/TiO2 nanoparticles

In recent years, the development of novel green chemistry routes for the synthesis of organic compounds has become very attractive to many research groups. Nanoparticles have been widely used because of their potential applications in catalysis, environmental remediation, electronic fields, biomedical, and industrial fields. In this article, a rapid, efficient, and simple approach was applied for the synthesis of 2,3‐diaminophenazine using a new photocatalytic system of CdFe₂O₄/TiO₂ nanoparticles in water as a benign solvent. The structure of the synthesized CdFe₂O₄/TiO₂ nanoparticle was confirmed using different methods such as transmission electron microscope (TEM), X‐ray diffraction (XRD), and magnetic measurements. It was found that the rate and yield of the photocatalytic synthesis of 2,3‐diaminophenazine were improved using CdFe₂O₄/TiO₂ nanoparticles compared to other methods.     

Rational eco-compatible synthesis and biological screening of new highly functionalized pyrido[2,3-a]carbazole derivatives: A novel class of antioxidant and anticancer agents

A solvent-free, one-pot, and operationally simple protocol was adopted to synthesize a new series of multifunctionalized pyrido[2,3-a]carbazole derivatives which were structurally characterized by FTIR, ¹H-NMR, ¹³C-NMR, and elemental analysis. The synthesized compounds were screened in vitro for their antibacterial activity and the compounds showed weak to moderate inhibition of bacterial growth. The antioxidant properties of the compounds were evaluated by their 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and total antioxidant capacity. Moreover, the cytotoxic effect of the compounds was examined on cancerous cell lines MCF-7 and A549 under in vitro conditions and the results showed that the compounds exhibited significant anticancer activity. Furthermore, the morphological changes and apoptosis induction were studied by inverted light microscopy, acridine orange/ethidium bromide, and 4′,6-diamidino-2-phenylindole dihydrochloride fluorescence microscopic analyses. The results indicated that among pyridocarbazole compounds, 2-ethoxy-8-chloro-4-(thiophen-2′-yl)-5,6-dihydro-11H-pyrido[2,3-a]carbazol-3-carboxamide 6g could be exploited as significant antioxidant and anticancer agents.     

An efficient catalytic method for the synthesis of pyrido[2,3‐d]pyrimidines as biologically drug candidates by using novel magnetic nanoparticles as a reusable catalyst

A convenient method for the synthesis of pyrido[2,3‐d]pyrimidines by using the novel nano‐magnetic silica‐bonded S‐sulfonic acid[Fe₃O₄@SiO₂@(CH₂)₃S–SO₃H] as an efficient and recyclable catalyst under neat conditions is described. The major advantages of the present methodology are high yield, short reaction time, and reusability of the catalyst. Furthermore, the nano‐magnetic silica‐bonded S‐sulfonic acid was fully characterized by using various techniques such as FT‐IR, TG/DTG, DTA, EDX, μXRF, XRD, HRTEM, SEM, SEM elemental mapping, XPS, and N₂ physisorption. The results obtained from this research support the idea of rational design, synthesis, and applications of task‐specific and reusable catalysts for the preparation of various polynitrogenated heterocyclic compounds containing 1,4‐dihydropyridine moieties.     

A convenient synthesis of novel 5-aryl-pyrido[2,3-d]pyrimidines and screening of their preliminary antibacterial properties

Exploiting the diene nature of 6-[1-aza-2-(dimethylamino)prop-l-enyl]-1,3-dimethyluracil (2), novel 5-aryl-pyrido[2,3-d]pyrimidines (5a–h) have been synthesized. The reaction proceeds through a triene intermediate whose structure has been conclusively established by single crystal X-ray analysis. Role of water is intriguing as the reaction can be stopped at the intermediate stage. Synthesized compounds have been screened for possible antibacterial properties and results showed modest activity.     

Nano‐Zn[2‐boromophenylsalicylaldiminemethylpyranopyrazole]Cl2 as a novel nanostructured Schiff base complex and catalyst for the synthesis of pyrano[2,3‐d]pyrimidinedione derivatives

Nano‐Zn[2‐boromophenylsalicylaldiminemethylpyranopyrazole]Cl₂ (nano‐[Zn‐2BSMP]Cl₂) as a novel nanostructured Schiff base complex was prepared and characterized using several techniques. Nano‐[Zn‐2BSMP]Cl₂ was used as an effective catalyst for the preparation of some pyrano[2,3‐d]pyrimidinedione derivatives by the multicomponent reaction of malononitrile, aryl aldehydes and barbituric acid derivatives. The novelty and efficiency of nano‐[Zn‐2BSMP]Cl₂ as a catalyst, in comparison with some other reported catalysts, for this synthetic transformation are the main features of this work.     

CoFe2O4@SiO2‐CPTES‐Guanidine‐Cu(II): A novel and reusable nanocatalyst for the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones and polyhydroquinolines and oxidation of sulfides

CoFe₂O₄@SiO₂‐CPTES‐Guanidine‐Cu(II) magnetic nanoparticles were synthesized and used as a new, inexpensive and efficient heterogeneous catalyst for the synthesis of polyhydroquinolines and 2,3‐dihydroquinazoline‐4(1H)‐ones and for the oxidation of sulfides. The structure of this nanocatalyst was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, X‐ray diffraction and inductively coupled plasma optical emission spectrometry. Simple preparation, high catalytic activity, simple operation, high yields, use of green solvents, easy magnetic separation and reusability of the catalyst are some of the advantages of this protocol.     

A novel dynamic kinetic resolution accompanied by intramolecular transesterification: asymmetric synthesis of a 4-hydroxymethyl-2-oxazolidinone from serinol derivatives

Reaction paths of the one-pot reaction of (R)-2-(α-methylbenzyl)amino-1,3-propanediol (1) and 2-chloroethyl chloroformate with DBU giving (4S,αR)-4-hydroxymethyl-3-(α-methylbenzyl)-2-oxazolidinone [(4S)-2] (94% de) were investigated. Intermediates of this reaction, 2-chloroethyl (2S)- and 2-chloroethyl (2R)-3-hydroxy-2-[(αR)-α-methylbenzyl]aminopropyl carbonates [(2S)-4 and (2R)-4], were synthesized individually. After the addition of DBU to the respective solution of the carbonate (2S)-4 and that of (2R)-4 in dichloromethane, the intramolecular transesterification between (2S)-4 and (2R)-4 and the diastereoselective intramolecular cyclization proceeded to afford (4S)-2 in high diastereomeric excess. Therefore, two monocarbonates (2S)-4 and (2R)-4 were kinetically resolved by this cyclization during the intramolecular transesterification between (2S)-4 and (2R)-4. We found that this process involved dynamic kinetic resolution accompanied by intramolecular transesterification.     

A novel peptide from Apis mellifera and solid-phase synthesis of its analogue

A novel peptide designated secapin-1,was purified and characterized from Apis mellifera.The molecular weight of 25 amino acid peptide secapin-1 was found to be 2821.5625 Da by ESI-FTICR-MS.It showed high identity to secapin.The sequence of secapin-1 was determined to be YIINVPPRCPPGSKFVKNKCRVIVP by automatic Edman degradation.A disulfide bond was formed between Cys⁹ and Cys²⁰ residues.In addition,an analogue of secapin-1 was synthesized by solid phase peptide synthesis method.The synthesis product was successfully purified and identified to homogeneity by using a combination of SEC,IEC,and RP-HPLC techniques.     

Unusual open chain quinolinyl peroxol and its alcohol counterpart obtained through a modified Skraup–Doebner–Von Miller quinoline synthesis: theoretical studies and complete 1H‐ and 13C‐NMR assignments

Because of their extreme instability, it is generally difficult to synthesize and fully characterize open chain peroxides, also known as peroxols. In our attempt to investigate the mechanism of the Skraup–Doebner–Von Miller quinoline synthesis, we were able to obtain an unusual open chain peroxy‐quinoline, namely, 4‐(8‐ethoxy‐2,3‐dihydro‐1H‐cyclopenta[c]quinolin‐4‐yl)butane‐1‐peroxol (1), and its alcohol counterpart, namely 4‐(8‐ethoxy‐2,3‐dihydro‐1H‐cyclopenta[c]quinolin‐4‐yl)butan‐1‐ol (2) obtained as a side product during the same reaction. Although structurally similar, these two compounds appeared to display some very distinct physical and spectroscopic characteristics. This work reports detailed NMR studies and full ¹H and ¹³ C NMR assignments for these two compounds. These assignments are based upon the analysis of the NMR spectra of these compounds including ¹H, ¹³ C, COSY, gHSQC and gHMBC. The effect of the peroxide functional group on the chemical shift of neighboring carbons and protons was also investigated by comparing the NMR data of these two compounds. Furthermore, the effects of potential hydrogen bondings in 1, 2, and possible 1–1 dimer, 2–2 dimer and in prototypical model systems, as well as the stability of these compounds, were investigated computationally. The computed dissociation energies and NMR data support the interpretation of the experimental data. Copyright © 2012 John Wiley & Sons, Ltd.     

Application of 1‐methyl imidazole‐based ionic liquid‐stabilized silica‐coated Fe3O4 as a novel modified magnetic nanocatalyst for the synthesis of pyrano[2,3‐d]pyrimidines

1‐Methyl imidazole‐based ionic liquid‐stabilized silica‐coated Fe₃O₄ magnetic nanoparticles [Fe₃O₄@SiO₂@(CH₂)₃‐1‐methyl imidazole]HSO₄ as a solid acid magnetic nanocatalyst was explored in the synthesis of pyrano[2,3‐d]pyrimidine derivatives. Pyrano[2,3‐d]pyrimidine derivatives were synthesized by a highly efficient three‐component reaction of various benzaldehydes, malononitrile, and barbituric acid. The catalyst was characterized by using various analysis techniques such as Fourier transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD), differential scanning calorimetry‐thermogravimetry analysis (DSC‐TGA), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM).     

Supramolecular Fe3O4@PEG/−diaza crown ether@Ni: a novel magnetically reusable nano catalyst for the clean synthesis of 2‐aryl‐2,3‐dihydroquinazolin‐4(1H)‐ones

Ni@diaza crown ether complex supported on magnetic nanoparticle was provided by grafting technique. The catalytic activity of Fe₃O₄@diaza crown ether@Ni was explored through one‐pot synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones and it was used as an efficient and recoverably constant nanocatalyst. FT‐IR, SEM, TEM, XRD, BET, ICP, EDS, and TGA techniques were employed to specify the nanocatalyst. This heterogeneous catalyst demonstrated acceptable recyclability and could be used again several times with no considerable loss of its catalytic activity.     

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.     

Copper(I) complex of 1,3‐DimethylBarbituric acid modified SBA‐15 and its catalytic role for the synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones and Imidazoles

An efficient one‐pot method for synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones and tri/tetra substituted‐1H‐imidazoles has been accomplished in the presence of catalytic amounts of Cu(I)‐1,3‐dimethylbarbituric acid modified SBA‐15 as heterogeneous catalyst with good to excellent yields. The catalyst is reusable and can be applied several times without any decrease in product yield. The synthesized catalyst was characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), energy dispersive X‐ray spectroscopy (EDS), thermal gravimetric analysis (TGA), N₂ adsorption/desorption isotherms (BET), Fourier transform infrared spectroscopy (FT‐IR) and atomic absorption spectroscopy (AAS).     

Synthesis and characterization of bromine source immobilized on diethylenetriamine‐functionalized magnetic nanoparticles: A novel,versatile and highly efficient reusable catalyst for organic synthesis

Bromine source immobilized on magnetic nanoparticles functionalized with diethylenetriamine was successfully synthesized and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometry, thermogravimetric analysis and X‐ray diffraction. The catalytic activity in the synthesis of 2,3‐dihydroquinazoline‐4(1H )‐one and polyhydroquinoline derivatives and in Knoevenagel condensation was studied. The bromine catalyst can be magnetically recovered and reused several times without significant loss of its catalytic activity. All products were obtained in high to excellent yields.     

A facile domino protocol for the regioselective synthesis and discovery of novel 2-amino-5-arylthieno-[2,3-b]thiophenes as antimycobacterial agents

A series of novel 2-amino-5-arylthieno[2,3-b]thiophenes has been synthesized regioselectively from the reaction of 5-aryldihydro-3(2H)-thiophenones with ethyl cyanoacetate/malononitrile and sulfur powder in the presence of morpholine under thermal as well as microwave irradiation conditions. This transformation presumably occurs via domino Gewald reaction-dehydrogenation sequence. The 2-amino-5-arylthieno[2,3-b]thiophenes were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv (MTB) and multi-drug resistant M. tuberculosis (MDR-TB). Among 12 compounds screened, ethyl 2-amino-5-(1-naphthyl)thieno[2,3-b]thiophene-3-carboxylate was found to be the most active compound with MIC of 1.1 μM against MTB and MDR-TB.