6395-83-1Relevant academic research and scientific papers
A new short synthetic approach to chlorocyclopentenones related to cryptosporiopsin via a ring expansion strategy: First synthesis of a fungitoxic metabolite from Sporormia affinis
Kabanyane, Sidima,Decken, Andreas,Yu, Chao-Mei,Strunz, George M.
, p. 270 - 274 (2000)
A metabolite of the coprophilous fungus, Sporormia affinis, 2-trans- allyl-5-chloro-1-hydroxy-4-oxo-2-cyclopentene-1-carboxylic acid methyl ester, 2, was synthesized in racemic form, by an eight-step sequence, in 11% overall yield. Departing from previous ring-contraction strategies for synthesis of chlorocyclopentenones in the cryptosporiopsin series, the key step in the new synthesis was ring expansion of a substituted cyclobutanone, the product of [2+2] cycloaddition of dichloroketene with methyl 2-trimethylsilyloxyhex-2- enoate.
CuCl/TMEDA/nor-AZADO-catalyzed aerobic oxidative acylation of amides with alcohols to produce imides
Kataoka, Kengo,Wachi, Keiju,Jin, Xiongjie,Suzuki, Kosuke,Sasano, Yusuke,Iwabuchi, Yoshiharu,Hasegawa, Jun-Ya,Mizuno, Noritaka,Yamaguchi, Kazuya
, p. 4756 - 4768 (2018/06/07)
Although aerobic oxidative acylation of amides with alcohols would be a good complement to classical synthetic methods for imides (e.g., acylation of amides with activated forms of carboxylic acids), to date, there have been no reports on oxidative acylation to produce imides. In this study, we successfully developed, for the first time, an efficient method for the synthesis of imides through aerobic oxidative acylation of amides with alcohols by employing a CuCl/TMEDA/nor-AZADO catalyst system (TMEDA = teramethylethylendiamine; nor-AZADO = 9-azanoradamantane N-oxyl). The proposed acylation proceeds through the following sequential reactions: aerobic oxidation of alcohols to aldehydes, nucleophilic addition of amides to the aldehydes to form hemiamidal intermediates, and aerobic oxidation of the hemiamidal intermediates to give the corresponding imides. This catalytic system utilizes O2 as the terminal oxidant and produces water as the sole by-product. An important point for realizing this efficient acylation system is the utilization of a TMEDA ligand, which, to the best of our knowledge, has not been employed in previously reported Cu/ligand/N-oxyl systems. Based on experimental evidence, we consider that plausible roles of TMEDA involve the promotion of both hemiamidal oxidation and regeneration of an active CuII-OH species from a CuI species. Here promotion of hemiamidal oxidation is particularly important. Employing the proposed system, various types of structurally diverse imides could be synthesized from various combinations of alcohols and amides, and gram-scale acylation was also successful. In addition, the proposed system was further applicable to the synthesis of α-ketocarbonyl compounds (i.e., α-ketoimides, α-ketoamides, and α-ketoesters) from 1,2-diols and nucleophiles (i.e., amides, amines, and alcohols).
Oxone-mediated oxidative cleavage of β-keto esters and 1,3-diketones to α-keto esters and 1,2-diketones in aqueous medium
Stergiou, Anastasios,Bariotaki, Anna,Kalaitzakis, Dimitris,Smonou, Ioulia
, p. 7268 - 7273 (2013/08/15)
A versatile and highly efficient method for the direct synthesis of α-keto esters and 1,2-diketones has been developed. This approach utilizes the oxidative cleavage of a variety of β-keto esters and 1,3-diketones mediated by an Oxone/aluminum trichloride system. The simple one-step oxidation reaction proceeded selectively in aqueous media to afford products in high yields, short reaction times, and environmentally benign conditions.
Synthesis of activated alkenylboronates from acetylenic esters by CuH-catalyzed 1,2-addition/transmetalation
Lipshutz, Bruce H.,Boskovic, Zarko V.,Aue, Donald H.
supporting information; experimental part, p. 10183 - 10186 (2009/05/30)
(Chemical Equation Presented) Stuck on an sp2 carbon: A new route to geometrically defined α-alkoxycarbonyl-substituted vinylboronates consists of the chemo- and stereoselective 1,2-addition of copper hydride to acetylenic esters followed by stereoretentive transmetalation with pinacolborane. This strategy is applied to the generation of an aryl acrylate intermediate in the synthesis of the antiinflammatory drug naproxen (see scheme).
Amines that transport protons across bilayer membranes: Synthesis, lysosomal neutralization, and two-phase pKa values by NMR
Dubowchik, Gene M.,Padilla, Linda,Edinger, Kurt,Firestone, Raymond A.
, p. 4676 - 4684 (2007/10/03)
It is desirable to be able to control the pH of lysosomes. A collection of lipophilic, nitrogenous bases, designed to act as membrane-active, catalytic proton transfer agents, were prepared and their effective pKas measured in a vigorously stirred, two-phase system. One phase was a phosphate buffer whose pH was varied over the range ca. 1-11. The other was an immiscible, deuterated organic solvent in which the compounds preferentially resided even when protonated. When chemical shift changes versus the pH of the buffer were plotted, clear pKa curves were generated that are relevant to transmembrane proton transfer behavior. The two-phase pKas increased with increasing counterion lipophilicity and with increasing organic solvent polarity. The compounds were also tested for their ability to neutralize the acidity of lysosomes, a model for other acidic vesicles involved in drug sorting. The most successful of these, imidazole 6a, has > 100 times the neutralizing power of ammonia, a standard lysosomotropic amine, causing a 1.7 unit rise in lysosomal pH of RAW cells at 0.1 mM, compared to a 0.2 and 1.4 unit rise for ammonium chloride at 0.1 and 10 mM, respectively.
Dihalogenation of β-ketosulfides. Synthesis of α-keto methyl esters and α-keto S-phenyl thioesters
Fortes,Souto,Okino
, p. 2045 - 2052 (2007/10/02)
α-Keto esters and α-keto S-phenyl thioesters are synthesized from β-keto sulfides by dihalogenation with sulfuryl chloride followed by solvolysis with methanol and acetone/water respectively.
Simple preparation of α-bromo acyl silanes α-ketoacyl silanes and α-ketoesters from silyl acetylenes
Bulman Page, Philip C.,Rosenthal, Stephen
, p. 2573 - 2586 (2007/10/02)
α-Bromo- and α-keto-acyl silanes may simply and efficiently be prepared in short reaction schemes from silyl acetylenes; α-ketoacyl silanes are also implicated in a one-pot synthesis of α-ketoesters from silyl acetylenes.
Catalytic Asymmetric Hydrogenation of Methyl (E)- and (Z)-2-Acetamido-3-alkylacrylates
Scott, John W.,Keith, Dennis D.,Nix, George,Parrish, David R.,Remington, Stuart,et al.
, p. 5086 - 5093 (2007/10/02)
Rhodium-chiral phosphine complex catalyzed homogeneous hydrogenations of methyl (Z)- and (E)-2-acetamido-4-methoxybut-2-enoates ((Z,E)-10), methyl (Z)- and (E)-2-acetamidohex-2-enoates ((Z,E)-16A) and methyl (Z)- and (E)-2-acetamido-4-methylpent-2-enoates ((Z,E)-16B) are reported.With phosphines in which two achiral phosphorus atoms are connected by a chiral four-carbon unit, higher product enantiomeric excesses (ee's) are obtained from E than from Z substrates.With phosphines in which a two-carbon chiral unit separates two achiral phosphorus atoms, Z substrates are preferred.With dipamp (28), both Z and E substrates (particularly (Z,E)-16A) are reduced with high enantioselectivity.The additional oxygen atom in substrates (Z,E)-10 has little effect on product ee with most phosphines.
