Design,Synthesis, Antimicrobial Evaluation,and Laccase Catalysis Effect of Novel Benzofuran–Oxadiazole and Benzofuran–Triazole Hybrids

Novel structural hybrids of benzofuran–oxadiazole and benzofuran–triazole have been synthesized and evaluated for their potential against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli. The excellent antibiotic activity was shown by compounds 5c and 9c against S. aureus with minimum inhibitory concentration values in 1.74–5.16 mg/mL range. The estimation of in vitro antifungal activity of synthetic compounds was performed against Trichoderma harzianum, Aspergillus niger, and Metarhizium anisopliae. Among compounds 5a – 5j , only 5h and 5i showed promising antifungal potential against T. harzianum and A. niger, whereas compound 5j showed enhanced antifungal effect only against A. niger when their activity values were compared with standard drug amphotericin. No pronounced antifungal activity was shown by synthesized compounds 9a–j , except for compound 9g , which was active against all fungal strains having minimum inhibitory concentration values in 1.90–2.03 mg/mL range. In addition to antimicrobial evaluation, the synthesized compounds were also analyzed to study their effects on the catalytic potential of laccase, and it was found that among all, compound 9b showed very strong activity with maximum relative reactivity of 145% at 0.03‐mM concentration.     

Ultrasound-Assisted Synthesis and In Silico Modeling of Methanesulfonyl-Piperazine-Based Dithiocarbamates as Potential Anticancer,Thrombolytic, and Hemolytic Structural Motifs

Piperazine-based dithiocarbamates serve as important scaffolds for numerous pharmacologically active drugs. The current study investigates the design and synthesis of a series of dithiocarbamates with a piperazine unit as well as their biological activities. Under ultrasound conditions, the corresponding piperazine-1-carbodithioates 5a–5j were synthesized from monosubstituted piperazine 2 and N-phenylacetamides 4a–4j in the presence of sodium acetate and carbon disulfide in methanol. The structures of the newly synthesized piperazines were confirmed, and their anti-lung carcinoma effects were evaluated. A cytotoxic assay was performed to assess the hemolytic and thrombolytic potential of the synthesized piperazines 5a–5j. The types of substituents on the aryl ring were found to affect the anticancer activity of piperazines 5a–5j. Piperazines containing 2-chlorophenyl (5b; cell viability = 25.11 ± 2.49) and 2,4-dimethylphenyl (5i; cell viability = 25.31 ± 3.62) moieties demonstrated the most potent antiproliferative activity. On the other hand, piperazines containing 3,4-dichlorophenyl (5d; 0.1%) and 3,4-dimethylphenyl (5j; 0.1%) rings demonstrated the least cytotoxicity. The piperazine with the 2,5-dimethoxyphenyl moiety (5h; 60.2%) showed the best thrombolytic effect. To determine the mode of binding, in silico modeling of the most potent piperazine (i.e., 5b) was performed, and the results were in accordance with those of antiproliferation. It exhibits a similar binding affinity to PQ10 and an efficient conformational alignment with the lipophilic site of PDE10A conserved for PQ10A.     

Synthetic applications and methodology development of Chan–Lam coupling: a review

Chan–Lam coupling is one of the most popular and easy methods to perform arylation of amines (N-arylations). This cross-coupling is generally performed by reacting aryl boronate derivatives with a variety of substrates involving nitrogen containing functional groups such as amines, amides, ureas, hydrazine, carbamates. This article summarizes the synthetic applications of this reaction and the efforts of scientists to develop novel and efficient methodologies for this reaction.

     

High-speed on-demand 3D printed bioresorbable vascular scaffolds

Recent development of the high-resolution Micro-Continuous Liquid Interface Production (μCLIP) process has enabled 3D printing of biomedical devices with micron-scale precision. Despite our recent success in demonstrating fabrication of bioresorbable vascular scaffolds (BVS) via μCLIP, key technical obstacles remain. Specifically, achieving comparable radial stiffness to nitinol stents required strut thickness of 400 μm. Such large struts would negatively affect blood flow through smaller coronary vessels. Low printing speed also made the process impractical for potential on-demand fabrication of patient-specific BVSs. Lack of a systematic optimization strategy capturing the sophisticated process-materials-performance dependencies impedes development of on-demand fabrication of BVSs and other biomedical devices. Herein, we developed a systematic method to optimize the entangled process parameters, such as materials strength/stiffness, exposure dosage, and fabrication speed. A dedicated speed working curve method was developed to calibrate the μCLIP process, which allowed experimental determination of dimensionally-accurate fabrication parameters. Composition of the citric acid-based bioresorbable ink (B-Ink?) was optimized to maximize BVS radial stiffness, allowing scaffold struts at clinically-relevant sizes. Through the described dual optimization, we have successfully fabricated BVSs with radial stiffness comparable to nitinol stents and strut thickness of 150 μm, which is comparable to the ABSORB GT1BVS. Fabrication of 2-cm long BVS with 5 μm, 10 μm, and 15 μm layer slicing can now be accomplished within 26.5, 15.3, and 11.3 min, respectively. The reported process optimization methods and high-speed, high-resolution 3D printing capability demonstrate a promising solution for on-demand fabrication of patient-specific biomedical devices.     

Ring opening of epoxides with <Emphasis Type="Italic">C</Emphasis>-nucleophiles

Ring opening of epoxides has been an area of interest for organic chemists, owing to their reactivity toward nucleophiles. Such reactions yield important products depending on the type of nucleophiles used. This review article covers the synthetic approaches (1991–2015) used for the ring opening of epoxides via carbon nucleophiles.     

Bernstein functions, complete hyperexpansivity and subnormality-II

Multivariable Bernstein functions are used to discover some interesting connections between multivariable completely hyperexpansive weighed shifts and multivariable subnormal weighted shifts.     

Rate Enhancement Effects in the Dabco Catalysed Synthesis of Hydroxyalkenoate Esters

Marked acceleration of the catalytic coupling of aldehydes with methyl acrylate is achieved by varying either the aldehyde or the catalytic system. Rapid and efficient formation of heterocyclic derivatives with significant synthetic potential is described.     

Thermal degradation behavior of blends of phenyl methacrylate-styrene copolymers with aluminum isopropoxide

Thermal degradation studies were carried out of copolymer phenyl methacrylate-styrene in the presence of aluminum isopropoxide to assess the stability and alteration of degradation mechanism using thermogravimetry-differential thermogravimetry (TG-DTG) in inert atmosphere and under vacuum using thermal volatilization analysis (TVA). After collecting the condensable volatile degradation products from TVA experiments and separating them by sub-ambient TVA, investigation and identification were effected out by IR spectroscopy and gas chromatography-mass spectrometry (GC-MS) techniques. The degradation products from the blends consisted of some additional products, i.e., isopropanol, phenol, methacrylic acid, ethyl benzene, benzene and a cyclic compound apart from similar products obtained from the degradation of pure copolymers. The mechanism of newly formed degradation products has been discussed in detail. This revised version was published online in August 2006 with corrections to the Cover Date.     

A new strategy to characterize the extent of reaction of thermoset elastomers

A new method for determining the extent of reaction of thermoset elastomers was developed based on equilibrium swelling and dynamic mechanical analysis (DMA). The extent of reaction was defined based on the molecular weight between crosslinks (M_c) of a polymer sample in relation to M_c at the onset of gelation and at complete reaction. The molecular weight between crosslinks was measured using equilibrium swelling, whereas rheology and DMA were used to determine the exact point of gelation and reaction completion, respectively. The extent of reaction of poly(1,8‐octanediol‐co‐citrate) at various polymerization conditions was investigated and this method was used to study the relationship between mechanical properties, molecular weight between crosslinks, and extent of reaction. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1318–1328, 2008