38018-61-0Relevant academic research and scientific papers
Ni-Catalyzed asymmetric reduction of α-keto-β-lactams: via DKR enabled by proton shuttling
Wang, Fangyuan,Tan, Xuefeng,Wu, Ting,Zheng, Long-Sheng,Chen, Gen-Qiang,Zhang, Xumu
supporting information, p. 15557 - 15560 (2020/12/30)
Chiral α-hydroxy-β-lactams are key fragments of many bioactive compounds and antibiotics, and the development of efficient synthetic methods for these compounds is of great value. The highly enantioselective dynamic kinetic resolution (DKR) of α-keto-β-lactams was realized via a novel proton shuttling strategy. A wide range of α-keto-β-lactams were reduced efficiently and enantioselectively by Ni-catalyzed asymmetric hydrogenation, providing the corresponding α-hydroxy-β-lactam derivatives with high yields and enantioselectivities (up to 92% yield, up to 94% ee). Deuterium-labelling experiments indicate that phenylphosphinic acid plays a pivotal role in the DKR of α-keto-β-lactams by promoting the enolization process. The synthetic potential of this protocol was demonstrated by its application in the synthesis of a key intermediate of Taxol and (+)-epi-Cytoxazone. This journal is
Visible light photocatalytic aerobic oxidative synthesis of imines from alcohols and amines on dye-sensitized TiO2
Xu, Hui,Shi, Ji-Long,Hao, Huimin,Li, Xia,Lang, Xianjun
, p. 128 - 135 (2019/01/04)
A general visible light photocatalytic protocol for the synthesis of imines via a two-step one-pot route on alizarin red S (ARS)-sensitized TiO2 was uncovered. This efficient synthesis protocol involves one step of the highly selective formation of aldehydes from the oxidation of alcohols with O2 on ARS-sensitized TiO2 photocatalyst, and a subsequent step of condensation of newly formed aldehydes with various amines on TiO2 to afford imines in one pot. Anatase TiO2 provides a versatile platform for catalytic amounts of ARS (0.67 mol%) to facilitate the electron transfer from dye traversing its conduction band to O2 under green LED irradiation. Moreover, the Lewis acid sites of TiO2 can promote the formation of imines from aldehydes and amines in very high isolated yields. We took advantage of both the photocatalytic and catalytic properties of TiO2 to significantly expand the scope of imines. Our work suggests that the synthetic applications of TiO2 photocatalysis can be achievable under mild conditions by exploring the excellent functionalities of TiO2.
Organocatalytic Mukaiyama Mannich Reactions of 2,5-Bis(trimethylsilyloxy)furan
Laws, Stephen W.,Howard, Sara Y.,Mato, Raquel,Meng, Shuyu,Fettinger, James C.,Shaw, Jared T.
supporting information, p. 5073 - 5077 (2019/07/03)
The organocatalytic synthesis of densely substituted mono- and bis-?-lactams involving the Mukaiyama Mannich addition of 2,5-bis(trimethylsilyloxy)furan to imines is described. Use of a ditoluenesulfonylimide catalyst produces ?-lactams from monoaddition, whereas a more acidic catalyst (triflic acid) produces fused bis-lactams from double addition. Optimized organocatalytic conditions allow for the selective synthesis of either desired core as well as the one-pot, multicomponent assembly of the trisubstituted monolactams from aldehydes, amines, and bis-trimethylsilyloxyfuran. An examination of chiral acids found these organocatalysts to be highly active and diastereoselective in the monoaddition reaction, albeit with no enantioselectivity.
Remarkable difference between five- and six- number-membered ring transition states for intramolecular proton transfer in excited state
Qin, Xiaozhuan,Ding, Ge,Wang, Zhenqiang,Zhang, Shengtao,Li, Hongru,Luo, Ziping,Gao, Fang
, p. 25 - 35 (2017/03/02)
In this study, a range of organic dyes were prepared to investigate difference between five- and six- number-membered ring transition states for internal proton transfer in excited state. Different strength intramolecular hydrogen bond in the target dyes
Paclitaxel Biosynthesis: Adenylation and Thiolation Domains of an NRPS TycA PheAT Module Produce Various Arylisoserine CoA Thioesters
Muchiri, Ruth,Walker, Kevin D.
, p. 1415 - 1425 (2017/03/23)
Structure-activity relationship studies show that the phenylisoserinyl moiety of paclitaxel (Taxol) is largely necessary for the effective anticancer activity. Several paclitaxel analogues with a variant isoserinyl side chain have improved pharmaceutical
Ir-Catalyzed C?H Amidation of Aldehydes with Stoichiometric/Catalytic Directing Group
Zhang, Yun-Fei,Wu, Bin,Shi, Zhang-Jie
supporting information, p. 17808 - 17812 (2016/11/28)
Ir-catalyzed sp2C?H amidation of aldehydes with various anilines as stoichiometric or catalytic directing groups was accomplished. A wide range of substrates were selectively amidated in good to excellent yields with broad functional group tolerance. The iridacycle complexes were isolated, characterized, and proved as key intermediates. Kinetic studies and Hammett plots provided detailed understandings of this amidation. According to the mechanism, the electron-rich ArSO2N3was proved effective for intermolecular sp3C?H amidation.
Enantioselective Synthesis of Hemiaminals via Pd-Catalyzed C-N Coupling with Chiral Bisphosphine Mono-oxides
Li, Hongming,Belyk, Kevin M.,Yin, Jingjun,Chen, Qinghao,Hyde, Alan,Ji, Yining,Oliver, Steven,Tudge, Matthew T.,Campeau, Louis-Charles,Campos, Kevin R.
supporting information, p. 13728 - 13731 (2016/01/15)
A novel approach to hemiaminal synthesis via palladium-catalyzed C-N coupling with chiral bisphosphine mono-oxides is described. This efficient new method exhibits a broad scope, provides a highly efficient synthesis of HCV drug candidate elbasvir, and has been applied to the synthesis of chiral N,N-acetals.
Identification and optimisation of 3,3-dimethyl-azetidin-2-ones as potent and selective inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1)
McCoull, William,Augustin, Martin,Blake, Caroline,Ertan, Anne,Kilgour, Elaine,Krapp, Stephan,Moore, Jane E.,Newcombe, Nicholas J.,Packer, Martin J.,Rees, Amanda,Revill, John,Scott, James S.,Selmi, Nidhal,Gerhardt, Stefan,Ogg, Derek J.,Steinbacher, Stefan,Whittamore, Paul R. O.
supporting information, p. 57 - 63 (2014/01/06)
3,3-Di-methyl-azetidin-2-ones were identified as potent and selective 11β-HSD1 inhibitors against the human and mouse forms of the enzyme. Structure guided optimisation of LLE was conducted, utilising a key polar interaction and identifying stereochemical preference for the 4S isomer. Metabolic stability was improved to afford oral exposure, providing tool compounds suitable for pre-clinical evaluation.
Grinding synthesis of schiff bases combined with infrared irradiation
Tong, Jian-Ying,Sun, Na-Bo,Wu, Hong-Ke
, p. 5399 - 5401 (2013/07/26)
Solid-phase synthesis combined with infrared irradiation promoted the formation of a series of Schiff bases in the condensation reaction between substituted benzaldehydes and anilines, in the solvent free. Benzaldehydes and anilines, containing either electron withdrawing or electron-releasing groups, were evaluated their substituent effect on the formation of the Schiff bases. Moreover, this new procedure is environmentally benign because no solvent was employed in the transformations.
Total regioselective transformation of aromatic aziridine 2-carboxamides into 2-aminoamides promoted by active manganese
Concellon, Jose M.,Rodriguez-Solla, Humberto,Del Amo, Vicente,Diaz, Pamela
supporting information; experimental part, p. 2407 - 2410 (2010/06/21)
(Figure Presented) A novel, totally regioselective transformation of aromatic N-4-methoxyphenylaziridine 2-carboxamides into 2-aminoamides promoted by active manganese (Mn) is reported. a-Amino ketones can be readily obtained by reaction of morpholine-der
