10.1039/c7ob02882b
The study explores the use of bis-(amino)cyclopropenylidene (BAC) as a non-covalent Br?nsted base catalyst in conjugate addition reactions, specifically in 1,4- and 1,6-conjugate additions of carbon nucleophiles to enones and p-quinone methides (p-QMs). The chemicals used in the study include a range of p-QMs, carbon nucleophiles such as diethyl malonate and 2-naphthols, and BAC as the catalyst. The purpose of these chemicals was to investigate the efficiency of BAC in facilitating the formation of unsymmetrical diaryl- and triarylmethanes, which are important in synthetic chemistry. The study demonstrated that BAC could effectively catalyze these reactions under mild conditions, yielding the desired products in good to excellent yields, thus providing a straightforward access to a variety of diaryl and triarylmethanes.
10.1016/j.bmcl.2020.127657
The research focused on synthesizing and evaluating simplified analogs of debromoaplysiatoxin (DAT) to enhance their anti-proliferative activity against cancer cells while minimizing adverse effects. The study synthesized a new derivative, 10-methyl-aplog-1 (1), and its analog 2, which features a naphthalene ring to improve CH/π interactions with the protein kinase C (PKC) δ-C1B domain. The synthesis involved multiple chemicals, including 6-hydroxy-1-naphthoic acid, diethyl malonate, and various protecting groups such as benzyl and triethylsilyl ethers. The results indicated that while the anti-proliferative activity of compound 2 was more potent than that of 1, its binding affinity to the PKC δ-C1B domain did not exceed that of 1, suggesting that further structural optimization is needed to enhance the interactions and therapeutic potential of these compounds.
10.1016/j.tetlet.2011.11.125
The research focuses on highly efficient thermal cyclization reactions of alkylidene esters in a continuous flow reactor system, aiming to synthesize aromatic and heteroaromatic derivatives. The study was conducted at temperatures ranging from 300–360°C and under high pressure conditions (100–160 bar) with short residence times (0.45–4.5 min) in tetrahydrofuran as a solvent. The process resulted in the synthesis of substituted heteroaromatic compounds, including pyridopyrimidinones and hydroxyquinolines, as well as naphthol and biphenyl derivatives, in moderate to high yields. The continuous flow methodology offered advantages such as ease of work-up, suitability for automation, and scalability, and was considered a greener alternative due to the use of a low-boiling point solvent that can be recycled, reducing waste. The chemicals used in the process included alkylidene b-diesters, Meldrum’s acid, malonic ester, cyanoacetic acid esters, and various amines for the synthesis of the precursors and the cyclization reactions.
10.1016/j.bmc.2010.03.015
The research focuses on the synthesis and anti-HIV activity of alkylated quinoline 2,4-diols, based on naturally occurring quinolone alkaloids, buchapine and compound 2. The study aimed to evaluate their potential as anti-HIV agents in human CD4+ T cell line CEM-GFP, infected with HIV1NL4.3 virus. A series of 45 alkylated derivatives were synthesized and tested for anti-HIV potential. The key intermediates, quinoline 2,4-diol and substituted quinoline 2,4-diol, were synthesized through condensation of aniline or substituted aniline with diethyl malonate under microwave irradiation. The synthesis involved various reactants such as prenyl bromide, K2CO3, DMF, and N-methyl 2-pyrolidone (NMP). The biological evaluation included cytotoxicity testing using an MTT-based cell viability assay and anti-HIV activity determination through p24 antigen capture ELISA. The analyses used included nuclear magnetic resonance (NMR), mass spectrometry (MS), infrared (IR) spectroscopy, high-performance liquid chromatography (HPLC), and elemental analysis to confirm the structure and purity of the synthesized compounds. The study identified several potent inhibitors, with compound 6 showing an IC50 value of 2.35 μM and a therapeutic index better than AZT, the standard anti-HIV drug.
10.1055/s-1982-30055
The research details an improved procedure for the Michael reaction of chalcones, a valuable C-C bond forming reaction commonly catalyzed by alkali metal hydroxides or alkoxides. The study aimed to achieve better results using weaker bases such as piperidine, tertiary amines, or quaternary ammonium hydroxides. The researchers found that partially dehydrated commercial barium hydroxide efficiently catalyzed Michael reactions of chalcones with active methylene compounds like ethyl malonate, ethyl acetoacetate, acetylacetone, nitromethane, and enolizable ketones such as cyclohexanone and acetophenone. The process involved stirring the components in ethanol at reflux or room temperature, yielding products with sharp melting points and single spots on T.L.C., and spectra that matched those of recrystallized products. The yields were generally higher than reported yields or at least of the same order, and the method was operationally simpler compared to other basic catalysts. The study concluded that while the barium hydroxide catalyst was cheap and easily prepared, its catalytic activity decreased over time when exposed to moist air, and the use of solvents other than ethanol or methanol led to poorer yields.
10.1016/j.bmc.2016.08.038
This research presents the synthesis and activity evaluation of cyclic dipeptides arylidene N-alkoxydiketopiperazines (DKPs), which are biologically active natural products with potential applications in medicine due to their antimicrobial, antitumor, antiviral, and plant growth regulation properties. The study aimed to design and stereoselectively synthesize a series of arylidene N-alkoxy DKPs and assess their antitumor activities and inhibitory effects against caspase-3, a key enzyme in apoptosis. The synthesis involved the use of various benzylic halides, diethyl malonate, nano-K2CO3, EtONO, and other reagents to produce compounds with different aryl and alkyl substitutions. The conclusions drawn from the research indicated that most of the synthesized DKPs exhibited antitumor activity, with compounds 6d, 6f, 6l, and 6o showing higher potency against certain tumor cell lines. Particularly, compound 6o demonstrated significant antitumor activity against K562-1, HCT-15, and A549 cells, with IC50 values of 7.3, 8.6, and 11.4 μM, respectively.
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