Robust Amino-Functionalized Mesoporous Silica Hollow Spheres Templated by CO2 Bubbles

Hollow-structured mesoporous silica has wide applications in catalysis and drug delivery due to its high surface area, large hollow space, and short diffusion mesochannels. However, the synthesis of hollow structures usually requires sacrificial templates, leading to increased production costs and environmental problems. Here, for the first time, amino-functionalized mesoporous silica hollow spheres were synthesized by using CO2 gaseous bubbles as templates. The assembly of anionic surfactants, co-structure directing agents, and inorganic silica precursors around CO2 bubbles formed the mesoporous silica shells. The hollow silica spheres, 200–400 nm in size with 20–30 nm spherical shell thickness, had abundant amine groups on the surface of the mesopores, indicating excellent applications for CO2 capture, Knoevenagel condensation reaction, and the controlled release of Drugs.

Agro-waste sourced catalyst as an eco-friendly and sustainable approach for Knoevenagel condensation reaction

Background: The present work describes an eco-friendly and sustainable approach for the Knoevenagel condensation of an aromatic aldehyde with ethyl cyanoacetate, and salicylaldehyde with Meldrum acid for the synthesis of ethyl benzylidenecyanoacetate and 3-carboxy coumarin (2-oxo-2H-1-benzopyran) derivatives, respectively. The reaction performed under greener catalytic media Water Extract of Watermelon Fruit Peel Ash (WEWFPA) is an eco-friendly protocol derived from the agro-waste feedstock. Various protocols have been reported for the synthesis of Knoevenagel condensation reaction using a hazardous catalyst or/and solvent found toxic to the environment, reaction time longer, poor yield, and required purification of the final product. The present method provides several added advantages of being completely greener, economic, giving high yield, inexpensive catalyst, and the final product isolated in pure form with good yield. Objective: The objective of the study was to develop a green methodology for the synthesis of ethyl benzylidenecyanoacetate and 3-carboxy coumarin derivatives. Results: The agro-waste based catalyst developed avoids the use of external inorganic/organic base, additives, and solvent-free synthesis of Knoevenagel condensation of ethyl benzylidenecyanoacetate and 3-carboxy coumarin derivatives under rt and microwave irradiation, respectively described. The microwave irradiation condition requires less time for the completion of the reaction and also gave better yield isolation Methods: We have demonstrated WEWFPA as a greener homogenous agro-waste is employed under rt stirring and microwave irradiation for the economic synthesis of ethyl benzylidenecyanoacetate and 3-carboxy coumarin derivatives. The developed method was found robust, non-hazardous and solvent-free with simple work-up gave target product. Conclusion: In conclusion, we have established an efficient, simple, agro-waste based catalytic approach for the synthesis of ethylbenzylidenecyanoacetate and 3-carboxy coumarin derivatives employing WEWFPA as an efficient catalyst under rt stirring and microwave synthesis, respectively. The method is a greener, economical and eco-friendly approach for the synthesis of Knoevenagel condensation products. The advantages of the present approach are solvent-free, no external metal, chemical base free, short reaction time and isolated product in good to excellent yields. The catalyst is agro-waste derived, which has abundant in natural sources, thus making the present approach a greener one.

Synthesis, Characterization and Catalytic Potency of Zn-based MOF for Knoevenagel Condensation Reaction

A Zn based metal organic framework with pyridine 2, 5-dicarboxylate (Zn-based MOF) were prepared as a reusable heterogeneous catalyst using solvothermal method. Zn-based MOF was used as heterogeneous catalyst for synthesis 5-arylidene malononitrile in ethanol under reflux condition. The attractive features of present method are mild reaction condition, short reaction time, simplicity, easy separation of catalyst and excellent yield. Keywords: Metal organic framework, heterogeneous catalyst, solvothermal method.

Solvatochromic and pH Switch Properties of a D–π–A Dye with benzo[b]thiophene as Donor Moiety

A charge transfer dye with the D–[Formula: see text]–A structure was synthesized by Pd catalyzed Hartwig–Buchwald coupling and Knoevenagel condensation reaction, using N, N-dihexylbenzo[b]thiophen-6-amine as donor and 2-(3-cyano-4, 5, 5-trimethylfuran-2 (5H)-ylidene)malononitrile (TCF) as acceptor. The solvatochromic and pH switch properties of the as-synthesized dye were investigated through UV-vis absorption and fluorescence emission spectra. A positive solvatochromism of the dye in different polar solvents was observed along with a visible color change of the solution. By adding acid/base into the DMSO solution of the dye, the color as well as the absorption and emission spectra of the solution exhibited outstanding characteristics of pH switch.

Facile synthesis of some 5-(3-substituted-thiophene)-pyrimidine derivatives and their pharmacological and computational studies

A series of 5-(3-substituted-thiophene)-pyrimidine derivatives (3a-d) were synthesized via Knoevenagel condensation reaction in aq. ethanol using H2O2:HCl as a catalyst. Their pharmacological effects were evaluated. Analytical and spectroscopic methods confirmed the structures of the target molecules. The antibacterial activity studies revealed that compounds 3b and 3d exhibited the most effective zone of inhibition against bacterial strains E. coli and S. aureus, respectively. The in vitro cytotoxicity was carried out by MTT assay against MCF-7 cell line. The results showed excellent selectivity for all four compounds, among which the compound 3a exhibited remarkable cytotoxicity with a minimum cell viability range of 23.68 to 44.16%. The interaction of compounds with calf thymus DNA was determined using UV-absorption spectroscopy. The results confirmed that all the synthesized compounds interacted strongly with CT DNA through electrostatic or groove binding. In silico ADME-toxicology studies indicated that all the molecules under investigation are non-toxic with good oral bioavailability. The drug-likeness score indicated that they are suitable as drug-leads. In silico molecular docking the specified compound 3b bound with GlcN-6-P and P38 MAPk with a minimum binding energy of –7.9 and –6.4 kcal/mol, respectively. DFT study demonstrated that compound 3d was chemically and biologically more reactive due to less energy gap.

Antibacterial Activity Testing on APMS (p-Methoxy Cinnamic Acid) Against Escherichia coli Bacteria

This study aims to determine whether the compound APMS (p-methoxy cinnamic acid) has the antibacterial activity of Escherichia coli and to determine the effective concentration of the compound APMS (p-methoxy cinnamic acid) in inhibiting the growth of Escherichia coli bacteria. This research begins with the synthesis of APMS obtained through the knoevenagel condensation reaction with the sonochemical method. The synthesized compounds were tested organoleptically and their melting points were measured. The structure of the results was elucidated using FT-IR and GC-MS, then tested the antibacterial activity of APMS compounds against Escherichia coli. Data analysis with SPSS, 99% confidence level (p<0.01) and continued with ANOVA test. The compound synthesized by APMS is in the form of fine crystals with a glossy white color, has a characteristic odor, and produces a % yield of 92.71%. The level of p-methoxy cinnamic acid (APMS) produced from this study was 95% using the GC-MS Instrument. APMS compounds have antibacterial activity against Escherichia coli. The average inhibition zone formed at a concentration of 5%; 10%; and 15% respectively are 0.695 cm; 0.727 cm; and 0.855 cm The optimal concentration of this study was at a concentration of 15% which gave the greatest inhibitionKeywords: Antibacterial; Escherichia coli; p-Methoxy cinnamic acidUji Aktivitas Antibakteri Senyawa APMS (Asam p_Metoksi Sinamat) Terhadap Bakteri Escherichia coli ABSTRAKPenelitian ini bertujuan untuk mengetahui apakah senyawa APMS (Asam p-metoksisinamat) memiliki aktivitas antibakteri Escherichia coli dan mengetahui konsentrasi efektif dari senyawa APMS (Asam p-metoksisinamat) dalam menghambat pertumbuhan bakteri Escherichia coli. Penelitian ini diawali dengan sintesis APMS ini didapatkan melalui reaksi kondensasi knoevenagel dengan metode sonokimia. Senyawa hasil sintesis diuji organoleptis dan diukur titik leburnya. Struktur hasil dielusidasi menggunakan FT-IR dan GC-MS, kemudian uji aktivitas antibakteri senyawa APMS terhadap Escherichia coli. Analisis data dengan SPSS, tingkat kepercayaan 99% (p<0,01) dan dilanjutkan uji ANOVA. Senyawa hasil sintesis APMS berupa kristal halus berwarna putih mengkilap, memiliki bau khas, dan menghasilkan % yield sebesar 92,71%. Kadar Asam Para Metoksisinamat (APMS) yang dihasilkan dari penelitian ini sebesar 95% menggunakan Instrumen GC-MS. Senyawa APMS memiliki aktivitas antibakteri terhadap Escherichia coli. Rataan zona hambat yang terbentuk pada konsentrasi 5%; 10%; dan 15% secara berturut adalah 0,695 cm; 0,727 cm; dan 0,855 cm Konsentrasi yang optimal dari penelitian ini adalah pada konsentrasi 15% yang memberikan daya hambat yang paling besar.Kata kunci: Antibakteri; Asam p-metoksi sinamat; Escherichia coli