10.1055/s-0035-1560565
The research focuses on the type 2 ring-opening reactions of cyclopropanated 7-oxabenzonorbornadienes with carboxylic acid nucleophiles. The experiments were designed to investigate the efficiency of these reactions under various conditions, using p-toluenesulfonic acid monohydrate as a catalyst in dichloroethane at 90°C. The study explored the impact of different acid catalysts, reaction temperatures, solvents, and nucleophile equivalencies on the reaction yield and rate. A range of carboxylic acids with varying pKa values were tested as nucleophiles, and the reactions were analyzed using techniques such as NMR, IR spectroscopy, and HRMS to characterize the products, which were 2-naphthylmethyl esters. The results showed a dependence of reaction rates on the acidity of the nucleophiles, with the optimal conditions yielding esters in moderate to decent yields. The study provides a new route for the synthesis of 2-naphthylmethyl esters and insights into the reactivity of similar fused-ring systems.
10.1002/adfm.201103147
The research focuses on the development of a new family of cationic charged biocompatible hybrid hydrogels, based on arginine unsaturated poly(ester amide) (Arg-UPEA) and Pluronic diacrylate (Pluronic-DA), which were fabricated through UV photocrosslinking in an aqueous medium. The purpose of this study was to improve the cellular interactions of synthetic hydrogels for potential biomedical applications by introducing cationic Arg-UPEA, which possesses biocompatibility and cationic properties. The conclusions drawn from the research indicate that the incorporation of Arg-UPEA into Pluronic-DA hydrogels significantly enhanced cell attachment, proliferation, and viability of both Detroit 539 human fibroblasts and bovine aortic endothelial cells. The chemicals used in the process include Pluronic F127, acryloyl chloride, triethylamine, Irgacure 2959 (as a photoinitiator), L-arginine, p-toluenesulfonic acid monohydrate, fumaryl chloride, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and p-nitrophenol, among others. These chemicals were utilized in the synthesis of the hydrogel precursors and for the characterization of their physicochemical properties.
10.1016/S0040-4020(98)01046-1
The research involves the synthesis and reactivity of bis(arylcarbamoyl)-N-arylphenacylamine oximes, which are precursors to N-unsubstituted O-arylcarbamoylhydroxylamines and 1,3-dihydroimidazol-2-ones. The study aimed to explore the Beckmann fragmentation and intramolecular cyclization of these compounds to form imidazol-2-ones. The researchers found that the expected Beckmann fragmentation did not occur under the tested conditions, and instead, the compounds underwent intramolecular nucleophilic addition, leading to the formation of imidazolidinones. The synthesis involved the use of N-arylphenacylamines, hydroxylamine hydrochloride, sodium acetate, aryl isocyanates, and TsOH.H2O (p-toluenesulfonic acid monohydrate), among other reagents. The conclusions of the research were that bis(arylcarbamoyl)-N-arylphenacylamine oximes are excellent precursors for the synthesis of the target compounds, and the reactions provided high yields of the desired products, with the process being confirmed through various analytical techniques including NMR, IR, and mass spectrometry.
10.1021/ol900581a
The research focuses on the development of an efficient one-pot three-component synthesis of 2-substituted N-Boc-4-iodopyrroles, which are valuable synthetic building blocks for pharmaceuticals and materials science. The purpose of this study was to create a mild and practical method for synthesizing these compounds using a Pd/Cu-catalyzed process that can be easily upscaled to produce multigrams of the desired product. The researchers successfully developed a method that involves the coupling of (hetero)aryl-, alkenyl-, and selected alkyl-substituted acid chlorides with N-Boc-protected propargylamine to produce ynones, which are then converted in a one-pot fashion to 2-substituted N-Boc-4-iodopyrroles. The process was found to be quite general with respect to the underlying acid chlorides, tolerating a variety of substituents. The study also demonstrated preliminary examples of a sequential coupling-addition-cyclocondensation-coupling sequence to 4-alkynyl-N-Boc-pyrroles in good yields, showcasing the versatility of this one-pot multicomponent strategy. Key chemicals used in the process include PdCl2(PPh3)2, CuI, triethylamine, acid chlorides, N-Boc-protected propargylamine, sodium iodide, and toluene-4-sulfonic acid monohydrate, among others.
10.1021/ol047774v
The study presents a diastereoselective synthesis method for the natural product (2S,5R)-5-hydroxypipecolic acid and its 6-substituted derivatives. The key step involves a highly diastereoselective epoxidation reaction of an enantiomerically pure cyclic enamide intermediate. Chemicals used include L-allysine ethylene acetal 4, Cbz-OSu for N-carbonylation, MeI for methylation, ptoluenesulfonic acid for cyclization-elimination, and oxone for epoxidation. The synthesis also involves N-acyliminium ion chemistry for the introduction of substituents at the 6-position. These chemicals serve to protect the amino acid, facilitate cyclization, and achieve the desired diastereoselectivity in the formation of the target compounds, which are important due to their presence in various plants, microorganisms, and as the core structure of numerous naturally occurring alkaloids.
Xi
