1921-90-0Relevant academic research and scientific papers
Synthesis of unsymmetrical dienones with heteroaromatic substituents
Vatsadze,Sviridenkova,Manaenkova,Semashko,Zyk
, p. 2224 - 2225 (2005)
Condensation of heteroaromatic aldehydes with 2-benzylidenecyclopentanone in a basic medium afforded a number of unsymmetrical 2,5- diarylidenecyclopentanones. According to 1H NMR data, the dienones obtained were the E,E-isomers.
Self-associated, "distillable" ionic media
Kreher, Ulf P.,Rosamilia, Anthony E.,Raston, Colin L.,Scott, Janet L.,Strauss, Christopher R.
, p. 387 - 393 (2004)
Liquid or low melting association products of carbon dioxide and a secondary amine, both neutral molecules that may be gaseous, are recognised as "distillable" ionic media.
Design and Green Synthesis of Piperlongumine Analogs and Their Antioxidant Activity against Cerebral Ischemia-Reperfusion Injury
Li, Ge,Zheng, Yuantie,Yao, Jiali,Hu, Linya,Liu, Qunpeng,Ke, Furong,Feng, Weixiao,Zhao, Ya,Yan, Pencheng,He, Wenfei,Deng, Hui,Qiu, Peihong,Li, Wulan,Wu, Jianzhang
, p. 4545 - 4557 (2019)
The supplementation of exogenous antioxidants to scavenge excessive reactive oxygen species (ROS) is an effective treatment for cerebral ischemia-reperfusion injury (CIRI) in stroke. Piperlongumine (PL), a natural alkaloid, has a great potential as a neur
Highly Enantioselective Iridium-Catalyzed Hydrogenation of Conjugated Trisubstituted Enones
Peters, Bram B. C.,Jongcharoenkamol, Jira,Krajangsri, Suppachai,Andersson, Pher G.
supporting information, p. 242 - 246 (2021/01/13)
Asymmetric hydrogenation of conjugated enones is one of the most efficient and straightforward methods to prepare optically active ketones. In this study, chiral bidentate Ir-N,P complexes were utilized to access these scaffolds for ketones bearing the stereogenic center at both the α- and β-positions. Excellent enantiomeric excesses, of up to 99%, were obtained, accompanied with good to high isolated yields. Challenging dialkyl substituted substrates, which are difficult to hydrogenate with satisfactory chiral induction, were hydrogenated in a highly enantioselective fashion.
Ruthenium-catalysed synthesis of chiral exocyclic allylic alcoholsviachemoselective transfer hydrogenation of 2-arylidene cycloalkanones
Zhang, Kaili,Liu, Qixing,He, Renke,Chen, Danyi,Deng, Zhangshuang,Huang, Nianyu,Zhou, Haifeng
supporting information, p. 1628 - 1632 (2021/03/09)
An exclusive asymmetric reduction of C=O bonds of 2-arylidene four-, five-, six-, and seven-membered cycloalkanones has been studied systematically. The asymmetric transfer hydrogenation was performed using a robust and commercially available chiral diamine-derived ruthenium complex as a catalyst and HCOOH/Et3N as a hydrogen source under mild conditions, giving 51 examples of chiral exocyclic allylic alcohols in up to 96% yield and 99% ee. This method was also applicable to the gram-scale synthesis of the active intermediates of the anti-inflammatory loxoprofen and natural product (?)-goniomitine.
Donor-acceptor bicyclopropyl configuration-fixed by an additional trimethylene bridge: synthesis and Lewis acid-catalyzed tandem three-membered rings opening
Denisov, D. A.,Novikov, R. A.,Tomilov, Yu. V.
, p. 1568 - 1574 (2021/09/04)
A diastereoselective synthesis of donor-acceptor bicyclopropyl, 8-phenyldispiro[2.3.2.0]-nonane-1,1-dicarboxylate, was carried out, which treated with Lewis acids acts as a synthetic equivalent of cis-1,6-zwitterionic intermediates. In the presence of GaC
Metal- and Solvent-Free Transesterification and Aldol Condensation Reactions by a Homogenous Recyclable Basic Ionic Liquid Based on the 1,3,5-Triazine Framework
Hu, Yanqiu,Kazemnejadi, Milad,Ren, Mingqi
, p. 775 - 783 (2021/08/30)
A new recyclable basic ionic liquid was introduced as an efficient catalyst for aldol condensation and transesterification reactions under environmentally friendly conditions. The catalyst was prepared based on methyl imidazolium moieties bearing hydroxide counter anions via the Hofmann elimination on a 1,3,5-triazine framework. The ionic liquid with two functionalities including anion stabilizer and high basicity, was used as an efficient catalyst for aldol condensation as well as transesterification reaction of a variety of alkyl benzoates. All reactions were performed in the absence of any external reagent, co-catalyst, or solvent, in line with environmental protection. The kinetics isotope effect (KIE) was conducted for the transesterification reaction to elucidate the mechanism and rate determining step (RDS). It worth noted that, the homogeneous catalyst could be recycled from the reaction mixture and reused for several consecutive runs with insignificant drop of basicity and conversion.
RhIII-Catalyzed Synthesis of Highly Substituted 2-Pyridones using Fluorinated Diazomalonate
Das, Debapratim,Sahoo, Gopal,Biswas, Aniruddha,Samanta, Rajarshi
supporting information, p. 360 - 364 (2020/01/25)
A RhIII-catalyzed strategy was developed for the rapid construction of highly substituted 2-pyridone scaffolds using α,β-unsaturated oximes and fluorinated diazomalonate. The reaction proceeds through direct, site-selective alkylation based on migratory insertion and subsequent cyclocondensation. A wide substrate scope with different functional groups was explored. The requirement of fluorinated diazomalonate was explored for this transformation. The developed methodology was further extended with the synthesis of the bioactive compound.
RuPHOX-Ru-Catalyzed Selective Asymmetric Hydrogenation of Exocyclic α,β-Unsaturated Pentanones
Li, Jing,Liu, Delong,Liu, Yangang,Lu, Yufei,Wang, Yanzhao,Zhang, Wanbin,Zhu, Yue
supporting information, (2019/08/26)
A RuPHOX-Ru catalyzed selective asymmetric hydrogenation of exocyclic α,β-unsaturated ketones has been developed, furnishing the corresponding chiral exocyclic allylic alcohols in high yields and with up to >99.5percent ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 10000 S/C) without any loss in reaction activity and enantioselectivity. The resulting hydrogenated products could be easily transformed to several biologically active compounds with high asymmetric performance. The asymmetric protocol provides an efficient methodology for the synthesis of chiral exocyclic allylic alcohols.
Bovine serum albumin-catalysed cross aldol condensation: Influence of ketone structure
Ardanaz, Sebastián M.,Borucki, Estefanía L.,Velez Rueda, Ana J.,Parisi, Gustavo,Iribarren, Adolfo M.,Iglesias, Luis E.
, p. 50 - 57 (2019/08/26)
Bovine serum albumin (BSA) catalyses the cross aldol condensation and proved to be catalytically active at mild temperature and in ethanol, a cheap and green solvent, contrasting with the strong or expensive reaction media usually employed for this reaction. We herein report the reaction of a set of ketones (butanone, 3-pentanone, cyclopentanone and cyclohexanone) with benzaldehyde and p-nitrobenzaldehyde which provided high conversions (77–95%) of the corresponding enones (isolated in a range of yields from 19% to 74%). Parameters assayed to achieve these conversion values were solvent, ketone/aldehyde molar ratio and temperature. In this procedure only cyclohexanone gave the bis-enone, by-product of the conventional aldol condensation, in low amount even at high benzaldehyde/cyclohexanone molar excess. Under the assayed conditions null or low ketol amounts were observed, except for the reaction of cyclopentanone and p-nitrobenzaldehyde. Moreover, kinetic data of BSA-catalysed aldol condensation of cyclohexanone and p-nitrobenzaldehyde suggest an ordered bi bi mechanism for enone formation; an enamine mechanism involving residues of the catalytic cavity exhibiting abnormal pKa values is also proposed.
