Refernces
10.1016/j.tetlet.2006.06.121
The research focuses on the one-pot synthesis of aldehydes or ketones from carboxylic acids through the in situ generation of Weinreb amides using the Deoxo-Fluor reagent. The methodology involves the conversion of carboxylic acids to corresponding aldehydes and ketones with high yield, highlighting the efficiency of Weinreb amides in nucleophilic reactions with DIBAL-H and Grignard reagents. The experiments utilized various carboxylic acids, including aliphatic, aromatic, and unsaturated types, along with N,O-dimethylhydroxylamine and iPr2NEt as reactants. The Deoxo-Fluor reagent was employed to generate Weinreb amides in situ, which were then reacted with organometallic reagents to produce ketones or aldehydes. The analyses used to determine the yield and purity of the products included gas chromatography (GC), mass spectrometry (GC–MS), and nuclear magnetic resonance spectroscopy (1H and 13C NMR).
10.1021/ja101292a
The study explores a novel method for nucleophilic acyl substitution via aromatic cation activation of carboxylic acids to rapidly generate acid chlorides under mild conditions. The researchers hypothesized that treating a carboxylic acid with a cyclopropene bearing geminal leaving groups would produce a cyclopropenium carboxylate intermediate, which could then undergo nucleophilic acyl substitution to yield a carboxylic acid derivative and cyclopropenone. They found that using 3,3-dichlorocyclopropenes effectively activated carboxylic acids, with the structure of the cyclopropene significantly influencing the reaction rate. For instance, replacing phenyl groups with isopropyl substituents in the cyclopropene accelerated the reaction. The addition of an amine base, such as Hünig's base, further enhanced the reaction rate. This method enabled the conversion of carboxylic acids to acid chlorides and subsequently to amides, even with acid-sensitive substrates. The study also demonstrated the potential for cyclopropenium-mediated peptide couplings, highlighting the versatility and mildness of this activation strategy for acylation technologies.
10.1021/jo971428s
The research explores a catalytic method for synthesizing carboxylated phosphines and phosphine oxides using palladium-catalyzed reactions. The primary goal is to improve the efficiency of chemical reactions by developing a flexible and rapid access to chiral ligands for use in enantioselective organometallic chemistry. The study focuses on the coupling of secondary phosphines with aryl triflates, using palladium catalysts like PdCl2(PPh3)2 and bases such as diisopropylethylamine in solvents like DMF. The research concludes that while the method successfully produces phosphine oxides, it has limitations, particularly with naphthalene derivatives. The findings suggest that the method is suitable for accessing aryl phosphine oxides and can be further explored for applications in two-phase organometallic chemistry.
10.1021/jacs.6b07230
The study focuses on using ynamides as novel racemization-free coupling reagents for amide and peptide synthesis under mild conditions. It introduces a two-step, one-pot synthetic strategy where ynamides facilitate the hydroacyloxylation of carboxylic acids followed by aminolysis, enabling efficient amide bond formation without the need for protecting functional groups like -OH, -SH, and ArNH2. The methodology highlights the advantages of ynamides in avoiding racemization, especially in peptide coupling, demonstrating excellent selectivity and broad applicability for various carboxylic acids and amines. The study shows potential for scaling up peptide synthesis, with applications in pharmaceutical and industrial processes.
10.1016/j.tetasy.2013.11.001
The study focuses on the total syntheses of both enantiomers of bacillamide C and neobacillamide A, natural products with bioactivity, and their optical activities. The researchers aimed to resolve the confusion regarding the absolute configurations of these metabolites, which have been derived from microorganisms growing in marine and terrestrial environments. They synthesized the compounds using a stereospecific route from D-(-)-alanine and compared the specific rotation of the synthesized compounds to those reported in literature. The results indicated that the absolute configurations previously proposed for bacillamide C and neobacillamide A should be revised to (S). This finding is significant for genomic studies of their biosynthesis and for the use of bacillamide C as a building block in bioactive cyclic peptides.
10.1016/j.ejmech.2013.10.058
The research focuses on the synthesis and evaluation of novel 2-chloro-4-anilino-quinazoline derivatives as dual inhibitors of EGFR (Epidermal Growth Factor Receptor) and VEGFR-2 (Vascular Endothelial Growth Factor Receptor 2), which are established targets in cancer therapy. The study aims to develop compounds that can synergistically enhance antitumor activity and prevent resistance. The experiments involved the synthesis of various 2-chloro-4-anilino-quinazoline derivatives, utilizing key intermediates such as 2,4-dichloro-quinazolines. Phosphorus Oxychloride (POCl3) was used in the synthesis of 2,4-dichloro-quinazolines from quinazolinediones. N,N-Diisopropylethylamine (DIPEA) was used as a base in the nucleophilic aromatic substitution reactions. The synthesized compounds were then tested for their inhibitory effects on EGFR and VEGFR-2 using a radiometric protein kinase assay. Additionally, molecular docking studies were conducted to understand the molecular interactions of these compounds with the kinase domains of EGFR and VEGFR-2. The results identified compound 8o as particularly potent, showing approximately 7-fold and 11-fold increased inhibition potency against VEGFR-2 and EGFR, respectively, compared to the prototype compound.
10.1016/S0960-894X(01)00782-X
The study focuses on the synthesis and biological activity of new 5-fluorocytosine derivatives, specifically 50-deoxy-N-alkyloxycarbonyl-5-fluorocytosine-50-carboxylic acid 6, which were designed to possess potent antitumor activity and low toxicity. The chemicals used in the study include 5-fluorocytosine, 1,1,1,3,3,3-hexamethyldisilazane, ammonium sulfate, b-dribofuranose 1,2,3,5-tetraacetate, N,N-diisopropylethylamine, alkyl chloroformate, sodium methoxide, and platinum oxide. These chemicals served various purposes in the synthetic route to produce the new derivatives, such as coupling agents, catalysts, and reagents for alkyloxycarbonylation, hydrolysis, and oxidation steps. The purpose of these chemicals was to create new compounds that could potentially replace or improve upon existing chemotherapeutic agents like 5-fluorouracil (5-FU) and capecitabine, offering more effective cancer treatment with fewer side effects.
10.1016/j.tetlet.2009.11.026
The study focuses on enhancing the efficiency of the selective monotosylation of 1,2-diols using dibutyl tin oxide (Bu2SnO) as a catalyst. The researchers discovered that the amount of Bu2SnO could be significantly reduced from 2 mol % to as low as 0.005 mol % while still achieving effective tosylation. They also found that the corresponding tin acetal 3b, derived from Bu2SnO and ethylene glycol, exhibited faster conversions and more reproducible reaction times compared to Bu2SnO alone. The study highlights the use of diisopropyl ethyl amine (iPr2NEt) as a base, which provided better purity of the product than triethylamine (Et3N). The research demonstrates that the tin acetal 3b can be used as a generic catalyst for selective diol tosylation, allowing further reduction in catalyst loading and achieving higher yields and better selectivities on various commercial diol substrates.
F, 
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