27150-99-8Relevant academic research and scientific papers
Development and Mechanistic Studies of the Iridium-Catalyzed C?H Alkenylation of Enamides with Vinyl Acetates: A Versatile Approach for Ketone Functionalization
Dong, Guangbin,Liu, Peng,Qi, Xiaotian,Zhou, Bo
supporting information, p. 20926 - 20934 (2021/08/18)
Ketone functionalization is a cornerstone of organic synthesis. Herein, we describe the development of an intermolecular C?H alkenylation of enamides with the feedstock chemical vinyl acetate to access diverse functionalized ketones. Enamides derived from various cyclic and acyclic ketones reacted efficiently, and a number of sensitive functional groups were tolerated. In this iridium-catalyzed transformation, two structurally and electronically similar alkenes—enamide and vinyl acetate—underwent selective cross-coupling through C?H activation. No reaction partner was used in large excess. The reaction is also pH- and redox-neutral with HOAc as the only stoichiometric by-product. Detailed experimental and computational studies revealed a reaction mechanism involving 1,2-Ir-C migratory insertion followed by syn-β-acetoxy elimination, which is different from that of previous vinyl acetate mediated C?H activation reactions. Finally, the alkenylation product can serve as a versatile intermediate to deliver a variety of structurally modified ketones.
Bismuth subnitrate-catalyzed markovnikov-type alkyne hydrations under batch and continuous flow conditions
?tv?s, Sándor B.,Fül?p, Ferenc,Szécsényi, Zsanett
, (2021/05/31)
Bismuth subnitrate is reported herein as a simple and efficient catalyst for the atom-economical synthesis of methyl ketones via Markovnikov-type alkyne hydration. Besides an effective batch process under reasonably mild conditions, a chemically intensified continuous flow protocol was also developed in a packed-bed system. The applicability of the methodologies was demonstrated through hydration of a diverse set of terminal acetylenes. By simply switching the reaction medium from methanol to methanol-d4, valuable trideuteromethyl ketones were also prepared. Due to the ready availability and nontoxicity of the heterogeneous catalyst, which eliminated the need for any special additives and/or harmful reagents, the presented processes display significant advances in terms of practicality and sustainability.
A step forward in solvent knitting strategies: Ruthenium and gold phosphine complex polymerization results in effective heterogenized catalysts
Valverde-González, Antonio,Marchal, Gwendoline,Maya, Eva M.,Iglesias, Marta
, p. 4552 - 4560 (2019/09/09)
Porous polymers based on ruthenium and gold triphenylphosphine complexes (KPhos(Ru), KPhos(Ru)Bi, KPhos(AuCl) and KPhos(AuNTf2)) were prepared via a cost-effective solvent knitting method with [RuHClCO(PPh3)3] or AuXPPh3 (X = Cl, NTf2) as single monomers or combined with biphenyl, which represents a further approach to obtain heterogenized catalysts. The resulting materials mainly preserve the metal coordination environment of their parent complexes, are stable up to 350 °C and have reasonable surface areas (250-300 m2 g-1 for KPhos(Ru)-polymers). KPhos(Ru)s selectively catalyze the imination of alcohols in the presence of base and the results for KPhos(Au)s show they are effective for the intermolecular hydration and hydroamination of alkynes. These materials can be reused several times without significant loss of activity. This novel and simple method affords heterogenized catalysts that combine the reactivity and selectivity of their homogeneous counterparts with the stability and reusability of a heterogeneous framework.
Formation of Acetals and Ketals from Carbonyl Compounds: A New and Highly Efficient Method Inspired by Cationic Palladium
Green, Shawn D.,Kindoll, Tyler,Lazaro-Martinez, Brenda,Mensah, Enoch A.,West, Jesse
, p. 1810 - 1814 (2019/09/09)
The development of a new, highly efficient, and simple method for masking carbonyl groups as acetals and ketals is described. This methodology relies on the nature of the palladium catalyst to direct the acetalization/ketalization reaction. This new protocol is mild and proceed with a very low catalyst loading at ambient temperatures. The method has been extended to a wide variety of different carbonyl compounds with various steric encumbrances to form the corresponding acetals and ketals in excellent yields.
Silver-Catalyzed Olefination of Acetals and Ketals with Diazoesters to β-Alkoxyacrylates
Li, Jiawen,Qian, Bo,Huang, Hanmin
supporting information, p. 7090 - 7094 (2018/11/23)
The first silver-catalyzed reaction of acetals or ketals with diazoesters leading to trisubstituted or tetrasubstituted β-alkoxyacrylates is now reported. A broad range of acetals and ketals bearing different substituents is compatible with this protocol and thus provides an attractive approach for the synthesis of complex β-alkoxyacrylates. The power of this method was further demonstrated by the successful synthesis of picoxystrobin, which is one of the most popular agricultural fungicides commercialized by Dupont.
Eco-friendly synthesis and antioxidant activity of new trifluoromethyl-substituted N-(pyrimidin-2-yl)benzo[d]thiazol-2-amines and some N-derivatives
Bonacorso, Helio G.,Calheiro, Tainara P.,Rodrigues, Melissa B.,Stefanello, Sílvio T.,Soares, Félix A. A.,Zanatta, Nilo,Martins, Marcos A. P.
, p. 2185 - 2194 (2016/11/17)
Abstract: A convenient and environmentally benign procedure for the synthesis of a new series of trifluoromethyl-substituted N-(pyrimidin-2-yl)benzo[d]thiazol-2-amines by the cyclocondensation reaction of (benzo[d]thiazolyl)guanidine with either 4-alkoxy-4-alkyl(aryl/heteroaryl)-1,1,1-trifluoroalk-3-en-2-ones or 2,2,2-trifluoro-1-(2-methoxycyclohexen-1-en-1-yl)ethanone is described. The main reactions were performed in refluxing water as the solvent (8–24?h), without catalysts, and the corresponding new N-(pyrimidinyl)-1H-(benzo[d]thiazolyl)amines were obtained at a 60–88?% yield. Subsequently, some di(hetero)arylamines were derivatized to the respective tertiary amines via easy N-alkylation and N-alkenylation reactions at 55–82?% yields. Finally, the Lipinski parameters and the total antioxidant activity of the new series of secondary arylamines were also evaluated. Graphical abstract: [Figure not available: see fulltext.]
Highly efficient acetalization of carbonyl compounds catalyzed by anilin-aldehyde resin salts
Tanemura, Kiyoshi,Suzuki, Tsuneo
supporting information, p. 797 - 799 (2015/06/22)
A mild procedures for the syntheses of ethylene acetals and dimethyl acetals from the corresponding aldehydes and ketones catalyzed by 1mol% of anilinealdehyde resin salts are described. This method is also useful for the synthesis of dimethyl acetals of diaryl ketones.
Efficient syntheses of ethyl 2-methylthio-and ethyl 2-benzylthio-6-methyl(aryl)pyrimidine-4-carboxylates and their carboxylic acid derivatives
Zanatta, Nilo,Fortes, Andressa S.,Bencke, Carlos E.,Marangoni, Mário A.,Camargo, Adriano F.,Fantinel, Cassio A.,Bonacorso, Helio G.,Martins, Marcos A. P.
, p. 827 - 835 (2015/03/14)
A simple and efficient procedure for the synthesis of ethyl 2-methylthio-and ethyl 2-benzylthio-6-methyl(aryl)-pyrimidine-4-carboxylates and their corresponding acid derivatives is reported. The products are obtained in good yields via the cyclocondensation reaction of ethyl 4-alkoxy-2-oxo-4-methyl(aryl)-but-3-enoates with 2-methylisothiourea sulfate or 2-benzylisothiourea hydrochloride, under mild, basic, aqueous conditions.
Anodic cleavage of several ketone N-phenylsemicarbazones into methyl N-phenylcarbamate and the corresponding dimethyl acetals
Nishikawa, Shinnosuke,Yamamori, Haruki,Ohashi, Kousuke,Okimoto, Mitsuhiro,Hoshi, Masayuki,Yoshida, Takashi
, p. 1766 - 1771 (2013/05/21)
Several ketone N-phenylsemicarbazones were electrooxidized in the presence of potassium iodide and a base using methanol as the solvent to give nearly commensurate amounts of methyl N-phenylcarbamate and the corresponding dimethyl acetals. Continuous evolution of gaseous nitrogen was observed from the anolyte during the electrooxidation. The reactions were carried out under very mild reaction conditions and are presumed to proceed through a four-electron oxidation process, in which the iodide ion plays an important role as an electron carrier.
Conjugation chemistry through acetals toward a dextran-based delivery system for controlled release of siRNA
Cui, Lina,Cohen, Jessica L.,Chu, Crystal K.,Wich, Peter R.,Kierstead, Paul H.,Frechet, Jean M. J.
, p. 15840 - 15848,9 (2020/08/24)
New conjugation chemistry for polysaccharides, exemplified by dextran, was developed to enable the attachment of therapeutic or other functional moieties to the polysaccharide through cleavable acetal linkages. The acid-lability of the acetal groups allows the release of therapeutics under acidic conditions, such as that of the endocytic compartments of cells, regenerating the original free polysaccharide in the end. The physical and chemical behavior of these acetal groups can be adjusted by modifying their stereoelectronic and steric properties, thereby providing materials with tunable degradation and release rates. We have applied this conjugation chemistry in the development of water-soluble siRNA carriers, namely acetal-linked amino-dextrans, with various amine structures attached through either slow- or fast-degrading acetal linker. The carriers with the best combination of amine moieties and structural composition of acetals showed high in vitro transfection efficiency and low cytotoxicity in the delivery of siRNA.
