10.1055/s-1996-4150
The study focuses on the synthesis of aliphatic 1,3-dinitro compounds, which can serve as precursors for various 1,3-difunctionalized compounds and heterocycles. The researchers developed a method to prepare these compounds by reacting primary aliphatic nitro compounds with primary or secondary α-nitroalkenes in the presence of catalytic amounts of triethylamine or potassium carbonate. The reactions were carried out at room temperature and yielded good results. The study also explored the reaction conditions and the yields and physical constants of the products. Additionally, the researchers investigated the instability of certain 2-aryl-1,3-dinitro compounds and the formation of by-products like isoxazolines and isoxazoles under specific conditions. The synthesized compounds were characterized using various spectroscopic techniques, and the structures of some compounds were confirmed through X-ray crystallography.
10.1021/ol900194v
The study explores an efficient method for converting aldoximes into nitrile oxides using iodobenzenediacetate (DIB) in methanol (MeOH) with a catalytic amount of trifluoroacetic acid (TFA). The nitrile oxides generated can be trapped in situ with olefins, leading to the formation of isoxazolines or isoxazoles, depending on the type of trap used. The study also investigates tandem oxidative processes, such as oxidative methoxylation or amidation of phenols, followed by intramolecular nitrile oxide cycloaddition (INOC), yielding synthetically valuable tricyclic intermediates. The findings demonstrate that DIB is an effective oxidant for aldoximes under these conditions, and the resulting intermediates hold potential for the synthesis of nitrogenous compounds.
10.1016/j.tetlet.2014.02.118
The study presents an environmentally benign method for synthesizing isoxazolines and isoxazoles via a cycloaddition reaction mediated by potassium chloride (KCl) in water. The key chemicals involved are aldoximes, which are oxidized to nitrile oxides by hypochlorous acid generated in situ from KCl and the oxidant Oxone?. These nitrile oxides then undergo a 1,3-dipolar cycloaddition with alkenes or alkynes to form the desired isoxazolines and isoxazoles. The process is optimized to achieve high yields and involves using KCl as a mediator, Oxone? as the oxidant, and water as the solvent, offering a green and efficient alternative to traditional methods.
10.1002/chem.200802652
The research study on the competitive reactions between ethyl nitroacetate and electron-deficient olefins under various reaction conditions and catalysts. The purpose of the study was to understand how these reactions could be modulated to favor either Michael additions or cycloaddition-condensations, leading to the formation of either Michael adducts or isoxazole derivatives, respectively. The researchers concluded that the reactions could be selectively steered towards one product or the other by adjusting the strength of the base and the presence of a copper(II) catalyst. Key chemicals used in the process included ethyl nitroacetate as the primary nitro compound, various electron-deficient olefins as dipolarophiles, and bases such as DABCO, DBU, and NMP, as well as copper(II) acetate as a catalyst. The study demonstrated that by manipulating the catalytic system, one could selectively form either Michael adducts or isoxazoline cycloadducts, marking the first report on such selective formation from primary nitro compounds through modulation of the catalytic system.
10.1002/jhet.194
The research involves the synthesis of a series of novel hybrid molecules that combine isoxazoles and benzodiazepines, with a dimethyl bicycloheptyl group added to enhance lipophilicity. The aim was to create compounds that could potentially act on multiple biological targets or enhance each other's activity. Key chemicals used in the synthesis include camphene, acetone, iron (III) nitrate nonahydrate, various aromatic aldehydes, and o-phenylenediamine. The synthesized compounds were characterized using techniques like NMR and IR spectroscopy. The compounds were then screened for their antibacterial and antifungal activities against a range of microbial strains, but none showed promising antimicrobial or antifungal activity up to concentrations of 180 μg/mL.