Refernces
10.1021/ja00408a020
The research investigates the kinetics and thermodynamics of keto-enol tautomerism in simple carbonyl compounds through the halogenation of cycloalkanones and aryl-substituted acetophenones at very low halogen concentrations (10??-10?? M). The purpose of this study is to provide a better understanding of the enolization process and the equilibrium between keto and enol forms, which is typically difficult to measure due to the low enol content. The researchers used bromine and iodine for halogenation reactions in water, with compounds such as cyclopentanone, cyclohexanone, and various substituted acetophenones as the carbonyl compounds. By analyzing the rate coefficients and equilibrium constants, they concluded that the enolization process is encounter-controlled and that the enol content is significantly lower than previously estimated by other methods like halogen titration. The study also established linear free-energy relationships for the tautomerism process and provided insights into the transition state of acid-catalyzed enolization. The results suggest that the enol ketonization rate constants are not equal to those for enol ether hydrolysis, and the equilibrium constants obtained in this study are more reliable than those derived from thermodynamic methods or halogen titration.
10.1016/j.bmcl.2010.06.045
The research focuses on the development of a new series of 6-(40-aryloxy-phenyl)vinyl-1,2,4-trioxanes, specifically compounds 10a–d, 11a–d, and 12a–d, which were synthesized and evaluated for their antimalarial activity against multidrug-resistant Plasmodium yoelii in Swiss mice via the oral route. The purpose of this study was to find structurally simpler, more affordable, and effective synthetic trioxanes that could combat multidrug-resistant malaria. The most active compounds in the series, trioxanes 10b and 10c, demonstrated 100% protection at a dose of 48 mg/kg over four days, comparable to the clinically useful drug β-arteether. The chemicals used in the synthesis process included various aryl alkoxyphenyl vinyl compounds, cyclopentanone, cyclohexanone, 2-adamantanone, and other reagents involved in the photooxygenation and acid-catalyzed condensation steps. The study concluded that cyclopentane-based trioxanes 10b and 10c showed promising activity profiles similar to that of β-arteether, indicating their potential as effective antimalarial agents.
10.1021/acs.orglett.0c00963
This research presents a novel directing-group-based strategy that enables the intermolecular Heck-type reaction of cycloketone oxime esters with unactivated alkenes, marking the first achievement in coupling nonstabilized alkyl radicals with unactivated olefins. The study's purpose was to develop a method for constructing Csp2?Csp3 bonds, which are significant in organic synthesis. Key chemicals used in the process include copper salts as catalysts, DMSO as an initial solvent, and 2-butanol, which was found to be the most effective solvent for controlling both regio- and diastereoselectivities. The reaction's compatibility with various unactivated alkenes and oxime esters derived from cyclobutanone, cyclopentanone, and cyclohexanone was demonstrated, showcasing the potential application of this methodology in organic synthesis.
10.1016/S0040-4039(00)87795-3
The study investigates the stereoselectivity of ketal Claisen rearrangements involving ketals of simple cyclic ketones such as cyclopentanone, cyclohexanone, and cycloheptanone. The reactions of these ketals with allylic alcohols produce mixtures of diastereomeric products, with the m isomer generally favored. The selectivity is influenced by enolization processes, particularly in the 5- and 6-membered ring systems. The study finds that the initial selectivity is quite good, especially when the allylic alcohol contains a methyl substituent, which induces significant diastereoselectivity. The identity of the major Claisen product is confirmed through independent methods like Wittig olefination and Cope rearrangement. The overall yields are good, and useful reaction products can be obtained, although the separation of isomers varies in difficulty depending on the cyclic ketone used. The researchers are working to expand the scope of the reaction to achieve higher diastereoselectivity.
10.1021/jo01353a009
The study explores the synthesis of various substituted naphthyridines and biphenyls through different chemical reactions. Key chemicals involved include N-(3-amino-4-picolylidene)-p-toluidine, which serves as a precursor for multiple reactions to produce compounds like 1,7-naphthyridine-2-aldoxime, 2,9-diaza-6,8-dihydro-7,7-dimethyl-5-oxoanthracene, and 7,9-diazabenz[f]indane. These compounds are formed by reacting the precursor with different reagents such as isonitrosoacetone, dimethyldihydroresorcinol, and cyclopentanone under specific conditions like heating and refluxing. The products are characterized by their melting points, yields, and elemental analysis. In another part of the study, the reaction of various p-aroylpropionic acids with benzoyl chloride is investigated, yielding substituted phthalides in the biphenyl series. The study also delves into the infrared and ultraviolet spectral analysis of these products to understand their structural properties.
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