10.1016/j.bmc.2019.05.026
The research focuses on the synthesis and evaluation of new pyrazolopyrimidine derivatives as potential inhibitors of Leishmania amazonensis arginase, an enzyme crucial for polyamine biosynthesis in the parasite. Six derivatives with varying substituents at the 4-position of the phenyl group were synthesized and tested for their inhibitory activity against recombinant L. amazonensis arginase (LaARG). The synthesis involved reactions of phenylhydrazine with malononitrile, formic acid, and phosphorous oxychloride to obtain the desired compounds, which were then confirmed through techniques like NMR, IR, EI-MS, and HRMS. The biological evaluation included determining the IC50 values, kinetic analysis of enzyme inhibition, and molecular docking studies to understand the interaction of these compounds with LaARG. Additionally, the compounds were assessed for their cytotoxicity on mammalian macrophages and their anti-leishmanicidal activity against L. amazonensis amastigotes. The study utilized various analytical methods such as high-performance liquid chromatography (HPLC) for purity assessment and molecular modeling for structural analysis of the enzyme-inhibitor complexes.
10.1007/s13738-015-0655-3
The research focuses on the development of a novel, cost-effective nanocatalyst, nano-sawdust-OSO3H, for the one-pot synthesis of biologically important pyrano[2,3-d]pyrimidines, which are known for their potential pharmaceutical applications such as antibacterial, antitumor, and analgesic activities. The experiments involved the use of reactants like barbituric acid or thiobarbituric acid, malononitrile, and a variety of aldehydes. The nanocatalyst was prepared by treating sawdust with chlorosulfonic acid, resulting in particles below 100 nm as observed through SEM imaging. The catalyst's morphology, chemical composition, thermal stability, and surface acidity were analyzed using techniques such as SEM, EDX, TGA/DTG, and FT-IR spectroscopy. The study demonstrated that nano-sawdust-OSO3H is an efficient catalyst, offering excellent yields in short reaction times and with mild reaction conditions, aligning with the principles of green chemistry.
10.3184/030823409X12615671424822
The study investigates the use of L-arginine as a cost-effective and recyclable catalyst for the synthesis of α,β-unsaturated nitriles and ketones through the Knoevenagel condensation reaction in an ionic liquid medium. The chemicals used include aromatic, heteroaromatic, and α,β-unsaturated aldehydes, which react with malononitrile and acetylacetone to produce the desired nitriles and ketones. The ionic liquid, 1-ethyl-3-methylimidazolium ethylsulfate, serves as a green and recyclable reaction medium, while L-arginine acts as the catalyst, providing moderate to excellent yields (45–100%) and being successfully recycled for five runs without significant loss of activity. This approach offers a green and facile method for the synthesis of these important fine chemical industry products, which have applications as pre-polymers, antihypertensive agents, and calcium antagonists.
10.1039/c6tc00203j
This research focused on the synthesis and characterization of organic push-pull type chromophores utilizing indane-1,3-dione-5-carboxylic acid (IDCA) and the novel 1,3-bis(dicyanomethylidene)indane-5-carboxylic acid (CICA) as electron acceptor fragments. The purpose was to develop nonlinear optical (NLO) active materials with enhanced performance by encapsulating the chromophores with dipole-shielding triphenylmethyl groups. The study concluded that the synthesized compounds, which included benzylidenes and azomethines with E double bond configuration, exhibited high amorphous phase stability and solution processability. The highest NLO efficiency was observed for a compound where the D-π-A molecule was encapsulated with triphenylmethyl groups at both donor and acceptor ends, demonstrating the potential of controlled stereochemistry in CICA-based compounds for photonic applications. Key chemicals used in the synthesis process included 5,5,5-triphenylpentan-1-ol, malononitrile, and various aldehydes and anilines for condensation reactions to form the desired chromophores.
10.1007/s00706-011-0651-y
The study presents an efficient method for synthesizing N-arylquinoline derivatives. The key chemicals involved in this study are aromatic aldehydes, 3-arylamino-5,5-dimethylcyclohex-2-enone, and active methylene compounds such as malononitrile or ethyl cyanoacetate. These compounds undergo a one-pot multicomponent reaction catalyzed by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in ethanol under microwave irradiation. The DBU acts as a catalyst to facilitate the reaction, while the microwave irradiation significantly reduces the reaction time and enhances the yield of the products. The study optimizes the reaction conditions, finding that using DBU at 5 mol% under 140 W microwave power at 80°C for 3 minutes yields the best results. This method is advantageous due to its mild reaction conditions, high product yields (92–99%), short reaction times (3–5 minutes), and compatibility with various functional groups, making it a green and efficient approach for synthesizing N-substituted quinoline derivatives, which are important in pharmaceuticals and exhibit a wide range of pharmacological activities.
10.1016/j.tetasy.2010.04.033
The study investigates the development of a new class of chiral guanidine organocatalysts. These catalysts feature a tunable electron-withdrawing group on the guanidine moiety, which allows for modulation of their catalytic activity. The researchers synthesized various chiral guanidines bearing different electron-withdrawing groups, such as nitrile, methanesulfonyl, p-toluenesulfonyl, and trifluoromethanesulfonyl. These guanidines were then tested in the Michael addition reaction of malononitrile to α,β-unsaturated imides. The study found that the guanidines could catalyze the reaction, with the enantioselectivity and reactivity being influenced by the nature of the electron-withdrawing group and the aromatic substituents. The best results were obtained with a guanidine catalyst bearing p-methoxyphenyl and p-toluenesulfonyl groups, which provided the product in an 81:19 enantiomeric ratio. The study demonstrates the potential of these chiral electron-poor guanidines as hydrogen-bonding catalysts for Michael addition reactions.
10.1039/c6md00381h
This study presents a catalyst- and protecting-group-free microwave-enhanced Friedlander synthesis for the rapid assembly of haloquinolines, compounds with potential antimicrobial and biofilm-clearing activities against drug-resistant and resistant bacteria. The study focused on improving the reaction yield of 8-hydroxyquinoline, known for its pharmaceutical applications, by comparing conventional oil bath heating with microwave irradiation. The researchers synthesized a series of haloquinolines and evaluated their antimicrobial activities against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and vancomycin-resistant Enterococcus faecium (VRE). They performed minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm-clearing concentration (MBEC) assays to evaluate the activities of these compounds. Nitrile compounds such as malononitrile were used to synthesize quinolines. The results showed that microwave-enhanced synthesis significantly improved the reaction yield (from an average of 34% to 72%) and discovered novel halogenated quinolines with biofilm-eliminating effects with MBEC ranging from 1.0 to 23.5 μM. The study also included a hemolytic assay to evaluate the toxicity of these compounds, with most of them showing negligible hemolytic activity at 200 μM. The study suggests that halogenated quinolines may be a promising class of compounds for the treatment of biofilm-associated infections.
10.1016/S1872-2067(12)60693-7
The study focuses on the synthesis of 4H-pyran derivatives using a silica-bonded N-propylpiperazine sodium n-propionate (SBPPSP) as a recyclable catalyst. The catalyst was prepared from commercially available and inexpensive starting materials and was used to catalyze the synthesis of various 4H-pyran derivatives, including 3,4-dihydropyrano[c]chromenes, 2-amino-4H-pyrans, 1,4-dihydropyrano[2,3-c]pyrazoles, and 2-amino-4H-benzo[e]chromenes. The chemicals used in the study included aromatic aldehydes, malononitrile, dimedone, ethyl acetoacetate, 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one, and α-naphthol, which served as reactants in the multi-component reactions to form the desired 4H-pyran derivatives. The purpose of these chemicals was to participate in condensation reactions under refluxing aqueous ethanol conditions, with SBPPSP facilitating the process and being easily recoverable and reusable, highlighting the environmental and economic benefits of the method.
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