New benzylpiperazine derivatives bearing mono‐ and bis‐dialkyl substituted 1,2,4‐triazoles

Cycloaddition of the 1‐aza‐2‐azoniaallenes 3 with p‐cyanobenzyl chlorides afforded, after spontaneous rearrangement, the 1,5‐dialkyl‐3‐[4‐chloromethyl)phenyl]‐1H‐[1,2,4]‐triazoles 6 . A series of 1,5‐dialkyl‐1H‐[1,2,4]‐triazol‐3‐yl)benzyl‐piperazines 7 and 8 were prepared from direct condensation of 6 with piperazine and N‐methylpiperazine, respectively. The structures of the newly synthesized products were identified by 2D NMR spectroscopy. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:28–32, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20061     

Structure and absolute configuration of hydroxy‐bis‐dihydrofarinosin from Encelia farinosa

The structure of the dimeric eudesmanolide hydroxy‐bis‐dihydrofarinosin ( 1 ) from Encelia farinosa followed after contrasting their ¹H and ¹³C NMR spectra with those of encelin ( 6 ), hydroxy‐bis‐dihydroencelin ( 3 ), and farinosin ( 4 ). Structure  1 was verified by single‐crystal X‐ray diffraction analysis, which further provided the stereochemistry of the hydroxy group at C‐4. Comparison of the experimental vibrational circular dichroism spectrum of its derived diacetate 2 with that calculated by density functional theory provided the absolute configuration, which resulted the same as that of its biogenetic precursor 4 . Evaluation of several chemical shift differences between the two eudesmanolide fragments of 1 and 3 allows also ascertaining the yet not reported absolute configuration of the C‐4 stereogenic center of 3 . Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and biological study of novel methylene‐bis‐chalcones and substituted methylene‐bis‐pyrimidines/pyrimidinones

A series of novel methylene‐bis‐chalcones was prepared by the reaction of 5,5′‐methylene‐bis‐salicylaldehyde with different acetophenones, subsequent treatment of methylene‐bis‐chalcones with urea/thiourea gave the corresponding methylene‐bis‐pyrimidinones/methylene‐bis‐mercaptopyrimidines in good yields. Characterization of the new compounds has been done by means of IR, ¹H NMR, MS and elemental analysis. The antibacterial, antitubercular and antifungal activity of the compounds has also been evaluated.     

Synthesis and characterization of proton‐conducting copolyimides bearing pendant sulfonic acid groups

A series of sulfonated copolyimides (co‐SPIs) bearing pendant sulfonic acid groups were synthesized from 1,4,5,8‐naphthalenetetracarboxylic dianhydride (NTDA), bis(3‐sulfopropoxy) benzidines (BSPBs), and common nonsulfonated diamines via statistical or sequenced polycondensation reactions. Membranes were prepared by casting their m‐cresol solutions. The co‐SPI membrane had a microphase‐separated structure composed of hydrophilic and hydrophobic domains, but the connecting behavior of hydrophilic domains was different from that of the homo‐SPIs. The co‐SPI membranes displayed clear anisotropic membrane swelling in water with negligibly small dimensional changes in the plane direction of the membrane. With water uptake values of 39–94 wt %, they showed dimensional changes in membrane thickness of about 0.11–0.58, which were much lower than those of homo‐SPIs. The proton conductivity σ values of co‐SPI membranes with ion exchange capacity values ranging from 1.95–2.32 meq/g increased sigmoidally with increasing relative humidity. They displayed σ values of 0.05–0.16 S/cm at 50 °C in liquid water. Increasing temperature up to 120 °C resulted in further increase in proton conductivity. The co‐SPI membranes showed relatively good conductivity stability during the aging treatment in water at 100 °C for 300 h. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1545–1553, 2005     

Synthesis of helical polyisocyanides bearing aza‐crown ether groups as pendant

We, herein, present a novel synthesis of responsive helical poly(aryl isocyanide)s bearing aza‐crown ethers as pendant groups. Chiral aryl isocyanide monomers bearing an aza‐crown ether as a pendant were designed and synthesized, piror to polymerization using a Pd‐Pt µ‐ethynediyl complex as an initiator to give the corresponding polymers in good yield. The resulting polyisocyanides adopted a stable helical structure in solution, as confirmed by circular dichroism spectroscopic analysis. In addition, the polymers were soluble in various solvents. Furthemore, the addition of suitable alkali metal ions to the crown ether of the sidechain on the helical polyisocyanide to form host‐gest complexes resulted in deformation of the helix due to electrostatic repulsion, and these phenomena depended on the size of metal cations. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 496–504.     

Design,Synthesis, and Characterization of Some New bis‐thiazoles

The essential idea of the work in this article is mainly dependent on the use of bis‐hydrazonoyl halides for heterocyclic synthesis. The present work describes preparation and characterization of new bis‐thiazoles from reaction of bis‐hydrazonoyl chlorides with thiosemicarbazones. The synthetic Schemes for the final compounds are proposed and discussed. Structures of the final products were elucidated by elemental analyses and Fourier transform infrared, mass spectrometry, ¹H, and ¹³C‐NMR spectra.     

One‐step synthesis of polycarbonates bearing pendant carboxyl groups by lipase‐catalyzed ring‐opening polymerization

The ring‐opening polymerization of a monomer containing a free carboxylic acid group is reported for the first time. The monomer, 5‐methyl‐5‐carboxyl‐1,3‐dioxan‐2‐one (MCC), was copolymerized with trimethylene carbonate (TMC) in an enzymatic ring‐opening polymerization conducted in bulk at 80 °C. The low‐melting TMC comonomer also solubilized the high‐melting MCC monomer, allowing for solvent‐free polymerizations. Six commercially available lipases were screened, and Candida antarctica lipase‐B (Novozym‐435) and Pseudomonas cepacia lipase were selected to catalyze the copolymerization because of their higher monomer conversions. Higher molecular weight polymers (weight‐average molecular weight = 7800–9200) were prepared when Novozym‐435 was used, with less MCC incorporated into the copolymer than used in the monomer feed. However, Pseudomonas cepacia lipase showed good agreement between the molar feed ratios and the molar composition, but the molecular weights (weight‐average molecular weight = 3600–4800) were lower than those obtained when Novozym‐435 was used. ¹³C NMR spectral data were used for microstructural analysis, which suggested the formation of random, linear, and pendant carboxylic acid groups containing polycarbonates with hydroxyl groups at both chain ends. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1267–1274, 2002     

Preparation of water‐soluble pullulans bearing pendant C60 and their aqueous solubility

Water‐soluble fullerene‐bearing pullulans were successfully prepared by the addition reaction of azide‐substituted pullulans with fullerene C₆₀ . The chemical structure of the products was characterized by IR, UV, and NMR spectroscopy. It was found that the saturation solubility of the C₆₀ moiety strongly depends on the degree of substitution (DS) of the sample, indicating that an optimum DS value of the C₆₀ moiety exists for its aqueous solubility.     

Specific lectin interactions and temperature‐induced reversible gels in novel water‐soluble glycopolymers bearing maltotrionolactone pendant groups

Glycopolymers based on the incorporation of a diaminobutylmaltotrionolactone onto activated ethylene‐vinyl alcohol, EVOH, copolymers with distinct composition in the former counit have been prepared. Previous transformation of initial hydroxyl EVOH groups to other more reactive functional groups has been required. The activation has been performed in this current investigation by functionalization with either 4‐nitrophenyl carbonate or o‐phthalic acid groups. The structure of the resulting novel water‐soluble glycopolymers has been confirmed by FTIR, ¹H and ¹³C‐NMR spectroscopies. In addition, the glass transition temperatures and thermal stability as well as the viscoelastic behavior in bulk and in water solution have been examined as a function of chemical linkage nature. The rheological evaluation confirms the reversible gel formation in all the cases. Finally, their affinity to Concanavalin A lectin has been also analyzed proving the feasible use of these glycopolymers as molecular recognition materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 719–729, 2010     

Ultrasound‐Assisted Facile Synthesis and Antimicrobial Studies of Alkanediyl‐bis‐thiazolidin‐4‐ones and Alkanediyl‐bis‐thiazinan‐4‐ones

Alkanediyl‐bis‐2‐aryl‐thiazolidin‐4‐one and alkanediyl‐bis‐2‐aryl‐1,3‐thiazinan‐4‐one derivatives have been congregated in a single step reaction of diaminoalkanes, aryl aldehydes, and sulfanyl acids in the presence of coupling agent N,N′‐dicyclohexylcarbodiimide under ultrasonic conditions. This method of constructing 4‐keto derivatives of thiazolidine and thiazinane is quick and clean besides yielding the products in quantitative yields. The spectral techniques corroborated the structures of the isolated products. Biological assay of the synthesized products has also been reported.     

Synthetic applications of 3H‐1,2,4‐dithiazoles: Structure and reactivity studies

Synthetic applications of 3H‐1,2,4‐dithiazoles have been studied extensively. The facile synthesis of hitherto unknown 3H‐1,2,4‐dithiazole S‐oxides was realized by the mCPBA oxidation of 3H‐1,2,4‐dithiazoles. The structural information of the 1,2,4‐dichalcogenazole ring system was revealed by the ORTEP analysis of 3‐tert‐butyl‐5‐4‐chloro‐phenyl‐3H‐1,2,4‐dithiazole S‐oxide. The reactivities of 3H‐1,2,4‐dithiazoles are also discussed. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:154–159, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20764     

New fluorescent bis‐β‐cyclodextrin‐indolizine sensor. Synthesis and sensing ability

The synthesis of 1,3‐[bis‐N‐6A‐deoxy‐β‐cyclodextrin‐6A‐yl‐aminocabonyl]‐7‐pyridin‐4‐yl indolizine is reported. The reaction proceeds by an amidation between 6‐amino‐β‐cyclodextrin and 1,3‐[bis‐(‐4‐nitrophenoxycarbonyl)‐7‐[pyridine‐4‐yl)] and yields the first sensor having in its structure the fluorescent indolizine and two β‐cyclodextrin fragments. The sensing ability towards phenol, p‐cresol and adamantan‐1‐ol has been evaluated by fluorescence spectroscopy. The molecular modelling study realised by MM3 and AM1 methods shows that non cooperative conformations are favoured, thus explaining that inclusion ability is not increased by such dimer, and that sensitivity is not enhanced as compared to corresponding monomeric sensors.     

Synthesis and microwave‐assisted catalytic activity of novel bis‐benzimidazole salts bearing furfuryl and thenyl moieties in Heck and Suzuki cross‐coupling reactions

A mixture of bis‐benzimidazole salts ( 1–7 ), Pd(OAc)₂ and K₂CO₃ in DMF ? H₂O catalyzes, in high yield, the Suzuki and Heck cross‐coupling reactions assisted by microwave irradiation in a short time. In particular, the yields of the Heck and Suzuki reactions with aryl bromides were found to be nearly quantative. The synthesized bis‐benzimidazole salts ( 1 – 7 ) were identified by ¹H? ¹³C NMR, IR spectroscopic methods and micro analysis. Copyright © 2010 John Wiley & Sons, Ltd.     

New P‐ligands: The aromaticity and reactivity of 2,4,6‐trialkylphenylphospholes

A further member of 2,4,6‐trialkyl‐phenyl‐phos‐pholes, the ditertbutylmethylphenyl derivative ( 1c ) was characterized by Bird index and by the sum of angles at the phosphorus atom to describe the flattening of the P‐pyramid. Both numbers suggested a slight aromaticity. The reaction of arylphospholes with phosphorus tribromide was extended to phosphole 1c leading this occasion, after further steps, to the mixture of 3‐ and 2‐substituted products ( 3c‐1 and 3c‐2 , respectively). A triisopropylphenyl‐2H‐phosphole ( 4 ) formed by sigmatropic rearrangement was utilized in the preparation of new 1‐phosphanorbornene derivatives, such as sulfide 6 and hemi‐oxides 8‐1 and 8‐2 . Further oxidation of the latter species ( 8‐1 and 8‐2 ) led to the decomposition of the dimeric structure ( 11 ). 4 could also be trapped by benzaldehyde to afford the oxaphosphanorbornene ( 10 ) as one diastereomer. Finally, the reversible formation of 2H‐phosphole 4 from 1H‐phosphole 1a at 150°C was proved. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:104–222, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20077     

Synthesis of 1,4‐phenylene‐bis‐aminomethanephosphonates: The stereochemical aspect

The synthesis of new 1,4‐phenylene‐bis‐(N‐alkylaminomethane)‐bis‐phosphonates 3Aa–3Da by the addition of dialkyl or diaryl phosphites to the azomethine bond of 1,4‐phenylene Schiff bases is reported. Some NMR studies on the stereochemistry of dialkyl phosphite addition to terephthalic bis‐imines showing the exclusive formation of the meso‐form are presented. The mechanism and the origin of such a high stereoselectivity are discussed. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:144–151, 2000     

N‐glycosylation approach to glucose‐functionalized diamine and its use for protection‐free synthesis of polyurea bearing glucoside pendant

A glucose‐functionalized diamine was prepared and used as a new monomer for polyurea synthesis. The diamine was prepared by N‐glycosylation of 1,6‐hexamethylenediamine with D ‐glucose. Upon adding diisocyanates to the diamine, isocyanate reacted selectively with the amino groups, not with the hydroxyl groups of the glucose‐derived structure, to give the corresponding polyureas. The polyureas exhibited highly hydrophilic nature due to the presence of the glucose‐derived side chain. A ternary system consisting of the glucose‐functionalized diamine, piperazine, and diisocyanate gave the corresponding polyureas, where content of the glucose‐derived moiety was tunable by feed ratio between the diamine and piperazine. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Synthesis and characterization of siloxane resins derived from silphenylene‐siloxane copolymers bearing benzocyclobutene pendant groups

Two bis(dimethylamimo)silanes with benzocyclobutene (BCB) groups, bis(dimethylamino)methyl(4′‐benzocyclobutenyl)silane ( 2 ) and bis(dimethylamino)methyl [2′‐(4′‐benzocyclobutenyl)vinyl]silane ( 4 ), were synthesized from different synthetic routes, which were then employed to prepare two novel silphenylene‐siloxane copolymers (SiBu and SiViBu) bearing latent reactive BCB groups by polycondensation procedure with 1,4‐bis(hydroxydimethylsilyl)benzene. At elevated temperatures these copolymers were readily converted to highly crosslinked films and molding disks with network structures by polymer chain crosslinking, which followed the first‐order kinetic reaction model. The final resins of SiBu and SiViBu demonstrated excellent thermal stability with high glass transition temperatures (218 and 256 °C) and high temperatures at 5% weight loss (553 and 526 °C in N₂, 530 and 508 °C in air). After aging at 300 °C in air for 100 h, the cured resins showed weight loss lower than 4%. The films of cured SiBu and SiViBu also exhibited relatively low dielectric constants of 2.66 and 2.64, low dissipation factors of 2.23 and 2.12 × 10^?3, low water absorptions (≤0.28%), and high transparence in the visible region with cutoff wavelengths of 321 and 314 nm. Moreover, the aged films exhibited good dielectric properties and low water absorptions. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7868–7881, 2008     

Mono‐ and bis‐tolylterpyridine iridium(III) complexes

The first structure report of trichlorido[4′‐(p‐tolyl)‐2,2′:6′,2′′‐terpyridine]iridium(III) dimethyl sulfoxide solvate, [IrCl₃(C₂₂H₁₇N₃)]·C₂H₆OS, (I), is presented, along with a higher‐symmetry setting of previously reported bis[4′‐(p‐tolyl)‐2,2′:6′,2′′‐terpyridine]iridium(III) tris(hexafluoridophosphate) acetonitrile disolvate, [Ir(C₂₂H₁₇N₃)₂](PF₆)₃·2C₂H₃N, (II) [Yoshikawa, Yamabe, Kanehisa, Kai, Takashima & Tsukahara (2007). Eur. J. Inorg. Chem. pp. 1911–1919]. For (I), the data were collected with synchrotron radiation and the dimethyl sulfoxide solvent molecule is disordered over three positions, one of which is an inversion center. The previously reported structure of (II) is presented in the more appropriate C2/c space group. The iridium complex and one PF₆⁻ anion lie on twofold axes in this structure, making half of the molecule unique.