1501-06-0Relevant articles and documents
1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU): A powerful catalyst for the Michael addition reaction of β-ketoesters to acrylates and enones
Muthusamy, Sengodagounder,Babu, Srinivasarao Arulananda,Gunanathan, Chidambaram
, p. 3247 - 3254 (2002)
The Michael addition reaction of 1,3-dicarbonyl compounds and enones was carried out in the presence of a catalytic amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in ethanol under the mild reaction condition furnished Michael adducts in excellent yield.
High-pH value chrome tanning aid containing polyfunctional group structure as well as preparation method and application thereof
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Paragraph 0035-0041; 0079, (2021/05/12)
The invention discloses a high-pH value chrome tanning aid containing a polyfunctional group structure as well as a preparation method and application thereof. The structure of the aid is a polyfunctional group compound containing ketone carboxylic ester. The invention discloses a preparation method of a high-pH value chrome tanning aid and a high-pH value chrome tanning application process. The chrome tanning aid structurally contains keto-carbonyl and carboxylic ester structures, and the keto-carbonyl and carboxylic ester structures react with arginine in collagen under the alkaline condition, so that collagen modification is achieved; carboxylic ester is hydrolyzed to generate carboxyl (-COOH), the number of collagen side chain carboxyl is increased, coordination sites with trivalent chromium are increased, high absorption of the chrome tanning agent is achieved, the concentration of trivalent chromium in chrome tanning wastewater is reduced, environmental pollution of the leather industry is reduced, and clean production of the leather industry is promoted; the method is easy to operate, and a new thought is provided for research of the high-pH value chrome tanning aid.
Chemoenzymatic Stereoselective Synthesis of Substituted γ- or δ-lactams with Two Chiral Centers via Transaminase-catalysed Dynamic Kinetic Resolution
Dong, Wenyue,Yao, Peiyuan,Wang, Yingang,Wu, Qiaqing,Zhu, Dunming
, p. 6311 - 6316 (2020/10/15)
The biocatalytic stereoselective synthesis of lactams with two chiral centers by a dynamic kinetic resolution strategy is demonstrated. Five transaminases were examined for the transamination of chemically synthesized substituted γ- or δ-keto esters. The application of (R)- and (S)-selective enzymes led to the corresponding chiral amines with moderate to high diastereomeric ratios and excellent enantiomeric excess, followed by the formation of γ- or δ-lactams in some cases. Reaction conditions including pH, co-solvent and ratio of amine donor vs. acceptor were optimised. The stereoselective biotransaminations were performed at semi-preparative scale, successfully generating the corresponding lactams or amine in 46–70 % isolated yields, up to 99 : 1 diastereomeric ratios and >99 % ee values. This study represents a promising approach to the biocatalytic synthesis of important γ- and δ-lactams with two chiral centers.
Five Roads That Converge at the Cyclic Peroxy-Criegee Intermediates: BF3-Catalyzed Synthesis of β-Hydroperoxy-β-peroxylactones
Vil, Vera A.,Gomes, Gabriel Dos Passos,Ekimova, Maria V.,Lyssenko, Konstantin A.,Syroeshkin, Mikhail A.,Nikishin, Gennady I.,Alabugin, Igor V.,Terent'Ev, Alexander O.
, p. 13427 - 13445 (2018/11/02)
We have discovered synthetic access to β-hydroperoxy-β-peroxylactones via BF3-catalyzed cyclizations of a variety of acyclic precursors, β-ketoesters and their silyl enol ethers, alkyl enol ethers, enol acetates, and cyclic acetals, with H2O2. Strikingly, independent of the choice of starting material, these reactions converge at the same β-hydroperoxy-β-peroxylactone products, i.e., the peroxy analogues of the previously elusive cyclic Criegee intermediate of the Baeyer-Villiger reaction. Computed thermodynamic parameters for the formation of the β-hydroperoxy-β-peroxylactones from silyl enol ethers, enol acetates, and cyclic acetals confirm that the β-peroxylactones indeed correspond to a deep energy minimum that connects a variety of the interconverting oxygen-rich species at this combined potential energy surface. The target β-hydroperoxy-β-peroxylactones were synthesized from β-ketoesters, and their silyl enol ethers, alkyl enol ethers, enol acetates, and cyclic acetals were obtained in 30-96% yields. These reactions proceed under mild conditions and open synthetic access to a broad selection of β-hydroperoxy-β-peroxylactones that are formed selectively even in those cases when alternative oxidation pathways can be expected. These β-peroxylactones are stable and can be useful for further synthetic transformations.
Coumarin derivatives protect against ischemic brain injury in rats
Sun, Mingna,Hu, Jinfeng,Song, Xiuyun,Wu, Donghui,Kong, Linglei,Sun, Yupeng,Wang, Dongmei,Wang, Yan,Chen, Naihong,Liu, Gang
, p. 39 - 53 (2013/10/01)
Neuroprotection strategies are of great importance in the treatment of ischemic brain injury. Screening of our in-stock coumarin derivatives identified compound 1 as exhibiting neuroprotective activity. Subsequently, a structural optimization was carried out, which led to the discovery of the potent compound 20. This compound signi ficantly attenuated the damage in a cell line derived from a pheochromocytoma of the rat adrenal medulla induced by oxygen-glucose deprivation in vitro. Furthermore, compound 20 exhibited clear neuroprotection in middle cerebral artery occlusion rats by reducing infarct size and brain-water content, improving neurological function, and suppressing neuronal loss and neuropathological changes in the cortex and hippocampus. Pharmacokinetic evaluation indicated that compound 20 could penetrate the blood-brain barrier of rats.
Copper(II) triflate catalyzed amination and aziridination of 2-Alkyl substituted 1,3-dicarbonyl compounds
Ton, Thi My Uyen,Tejo, Ciputra,Tiong, Diane Ling Ying,Chan, Philip Wai Hong
experimental part, p. 7344 - 7350 (2012/06/16)
A method to prepare α-acyl-β-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu(OTf)2 + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhI=NTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic C-H bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the β-aminated adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2-3 equiv was discovered to result in preferential formal aziridination of the C-C bond of the 2-alkyl substituent of the starting material and formation of the aziridine product.
Method for preparing chiral diphosphines
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, (2008/06/13)
The invention concerns a method for preparing a compound of formula (1) wherein: A represents naphthyl or phenyl optionally substituted; and Ar1, Ar2independently represent a saturated or aromatic carbocyclic group, optionally substituted.
Asymmetric hydrogenation method of a ketonic compound and derivative
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, (2008/06/13)
The present invention relates to a process for the asymmetric hydrogenation of a ketonic compound and derivative. The invention relates to the use of optically active metal complexes as catalysts for the asymmetric hydrogenation of a ketonic compound and derivative. The process for the asymmetric hydrogenation of a ketonic compound and derivative is characterized in that the asymmetric hydrogenation of said compound is carried out in the presence of an effective amount of a metal complex comprising as ligand an optically active diphosphine corresponding to one of the following formulae: STR1
SYNTHESIS OF POLYFUNCTIONAL ALIPHATIC CARBONYL COMPOUNDS UNDER PHASE-TRANSFER CONDITIONS
Sizov, A. Yu.,Dombrovskii, V. A.,Yanovskaya, L. A.
, p. 955 - 961 (2007/10/02)
We have studied mono- and dialkylation of malonic, acetoacetic, and cyanoacetic esters with esters of haloacetic and β-halopropionic acids and addition of the CH acids mentioned and their analogues to methyl and ethyl acrylate under phase-transfer catalysis conditions, and also deethoxycarbonylation of the obtained products.We have demonstrated for the first time the possibility of Dieckmann cyclization under phase-transfer catalysis conditions and have developed a simple method for the synthesis of 2,3-di(ethoxycarbonyl)cyclopentanone, a key intermediate in the synthesis of deoxyprostaglandins, by cyclization of triethyl 1,2,4-butanetricarboxylate.
ENZYMATIC REACTIONS IN ORGANIC SYNTHESIS 4- HYDROLYSES OF DIESTERS
Jeso, B. De,Drouillard, S.,Degueil-Castaing, M.,Saux, A.,Maillard, B.
, p. 1691 - 1698 (2007/10/02)
Enzymatic hydrolyses allowed discriminations of esters functions present in the same molecule.
