Synthetic Communications最新文献

A series of highly reusable heterogeneous catalysts (10-40 wt.% SiMo₁₂/Al₂O₃), consisting of molybdosilicic acid (SiMo₁₂) impregnated on alumina (Al₂O₃) support was synthesized by the wetness impregnation method. The physicochemical properties of synthesized catalyst were studied using FT-IR, XRD, SEM, EDX, TEM, BET and TG-DTA analysis techniques. The study proves that the synthesized SiMo₁₂ catalyst efficiently incorporated on the surface of Al₂O_3. The catalytic activity of prepared catalyst was investigated for the synthesis of pyranopyrazole(6-amino-4-phenyl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5carbonitrile) via cyclocondensation reaction of aldehydes, malononitrile, hydrazine hydrate and ethyl-acetoacetate under solvent-free conditions. Among different catalysts, 30% SiMo₁₂ supported on to Al₂O₃ showed the highest catalytic activity. High yield, shorter reaction time, operational simplicity, solvent-free conditions and reusability of the catalyst are the distinct features of this protocol.

The current study includes synthetic approaches for some linear heterocyclic compounds containing chromone moiety. Chromenopyridopyrimidine bearing amino-thione functions 4 was efficiently synthesized starting from 6,8-dimethylchromone-3-carbonitrile (1). The novel chromenopyridothiadiazolopyrimidines were synthesized through condensation of the key precursor 4 with some mono-electrophilic reagents. In addition, heteroannulated chromenopyridopyrimidothiadiazines were synthesized through condensation of compound 4 with some α-halogenated carbonyl reagents. The synthesized products were examined for their antimicrobial efficiency appearing remarkable activity against the inspected microorganisms especially compounds 7, 12 and 14. The synthesized products were inferred using analytical and spectral data.

Potassium phthalimide (PPI) and Potassium phthalimide-N-oxyl (POPINO) have emerged as a versatile and efficient catalyst in various organic synthesis reactions, playing a crucial role in the development of sustainable and environmentally friendly synthetic methodologies. This review highlights the catalytic applications of PPI and POPINO in diverse transformations, showcasing its potential as a valuable tool in modern organic synthesis. The multifaceted reactivity of PPI and POPINO has been explored in reactions such as nucleophilic substitutions, condensations, cycloadditions, and oxidation processes, making it an attractive catalyst for the synthesis of complex organic molecules.

The asymmetric Diels–Alder reaction of chalcone and isoprene has been accomplished by use of chiral titanium complexes. Notably, an enantiomeric excess as high as 61% and a regioselectivity of 95% have been achieved. The preparation of the chiral titanium complexes is simple and does not require the pre-installation of a chiral auxiliary. This study represents the first example of asymmetric Diels–Alder reaction between chalcone and isoprene.

Polyethyleneimine-supported cobalt (II) chloride as a novel polymeric nanocomposite acidic catalyst for the one-stage transesterification reaction of ethyl acetate with various alcohols is reported. The catalyst was characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, dynamic light scattering technique, and thermal gravimetric analysis. Furthermore, inductively coupled plasma and atomic absorption spectroscopy were used to determine the quantity of Cobalt nanoparticles in the catalyst. By adding the catalyst (0.10 g, 0.20 mol%) and n-hexane/chloroform (5.0 cm³) as solvent under reflux conditions, the studies demonstrated successful transesterification reactions with excellent yields (80–98%) and short reaction times (0.50–1.30 h) using various substrates on the scale of 1.0 mmol. Seven consecutive reactions could be performed on the catalyst without significantly decreasing its activity. The most noteworthy aspects of this process are its low cost, safety, and environmental friendliness due to the catalyst’s non-toxicity, straightforward operation, and effective outcomes.

An effective, green and eco-friendly method was developed to synthesize 1H-benzimidazole under microwave irradiation. The reactions of substituted o-phenylenediamine with DMF were efficiently promoted by butanoic acid, and the desired product 1H-benzimidazole derivatives were obtained in good to excellent yields. Compared with the conventional heating method, microwave irradiation significantly reduced the reaction time and improved the yields of the target products.

The poor selectivity, significant toxicity, high cost, and emergence of resistance of conventional chemotherapies are driving motive for the ongoing search for novel anticancer agents. New pyrano[2,3-c]pyrazolopyrimidines were synthesized and examined as antiproliferative agents, and the possible molecular mechanism(s) of action were explored. The mass and elemental analyses, alongside the IR,¹H, and ¹³C NMR spectra, confirmed the proposed structures of the obtained compounds. Derivatives 4 and 7 demonstrated the best antiproliferative profile against HepG2 cancer cells at 4 µM, with a high selectivity index of ∼7–9 folds. They increased the S phase cell population by 51% and 40% and caused a 5- and 11-fold increase in the p21 protein. Compound 7 was superior in inhibiting HepG2 cell migration and delayed wound healing, reducing migration rates by 55% and 90%, respectively. Future studies on the pharmacokinetics, pharmacodynamics, antimetastatic, and antitumor activities in animal models would be a robust advance.

Over the last few years, benzimidazole-heterocycle hybrid compounds have received considerable attention due to the wide spectrum of their biological property and many important chemical and pharmacological applications. These compounds have revealed antibacterial, antimicrobial, anticoagulant, antidiabetic and other activities, and they have been used as drugs in the market to treat several diseases. Furthermore, hybrid heterocyclic compounds possessing a benzimidazole skeleton exhibit significant complexing and anticorrosive properties. All of these applications have favored the development of a large number of synthetic strategies to prepare these heterocyclic systems in different reaction conditions. Many research articles on the synthesis of benzimidazole-heterocycle hybrid compounds have been reported in the literature. In this review, we present and discuss the synthetic routes of several benzimidazole-heterocycle hybrid compounds.

A catalyst free oxone mediated synthesizing N-alkyl 1, 4-dihydroquinoxaline-2,3-dione has been developed by oxidation of the N-alkyl quinoxalin-2(1H)-one. The developed method is a novel, safest, cost-effective, industrially viable method and applicable for N-substituted and without substitution of 1,4-dihydroquinoxaline-2,3-dione. Consequently, the process is applicable to a broad spectrum of functionality. The reaction can be performed in all organic solvents without any further heating with an extended time and without generating side products. This novel synthetic methodology using Oxone is believed to be the shortest and most efficient to prepare various key intermediates which can be used for further derivatization to make the different biologically active molecules, the key feature of this methodology is not solvent specific, all organic solvents giving the optimum purity and quality using the same reaction condition.

A broad scope of quinazolin-4(3H)-ones or benzothiadiazine 1,1-dioxides was obtained via a transition-metal free and convenient method. This approach involving KHSO₄ promoted cyclization and dehydration between diverse functionalized 2-aminobenzamides or 2-aminobenzenesulfonamides and N, N-dimethylformamide derivatives. The protocol offers moderate to excellent yields (45%-93%) under mild condition in a short of reaction time of 6 hours. The use of an environment-friendly and less expensive catalyst KHSO₄ also makes this protocol more attractive.