89201-84-3Relevant articles and documents
Iron powder and tin/tin chloride as new reducing agents of Meerwein arylation reaction with unexpected recycling to anilines
Abdelwahab, Ahmed B.,El-Sawy, Eslam R.,Kirsch, Gilbert
supporting information, p. 526 - 538 (2020/01/08)
Simple and rapid route for Meerwein arylation reaction using iron powder or a mixture of tin/tin chloride has been developed. In the presence of iron powder, different aryl diazonium salts reacted with methyl vinyl ketone, acrylates, and isopropenyl acetate. Production of oximes was detected as the main product with acrylates or in a mixture with β-aryl methyl ketones in the case of methyl vinyl ketone. The in situ produced HNO2 from an excess of NaNO2/HCl was trapped by alkyl aryl radical to form oximes in the E configuration form. The presence of tin/tin chloride mixture in the reaction of the aryl diazonium salts with methyl vinyl ketone produced Michael products along with β-aryl methyl ketones. The predicted α-aryl methyl ketones from the reaction of isopropenyl acetate with the diazotized anilines were obtained using iron or tin/tin chloride mixture.
Enantioselective Iridium-Catalyzed Allylation of Acetylenic Ketones via 2-Propanol-Mediated Reductive Coupling of Allyl Acetate: C14-C23 of Pladienolide D
Brito, Gilmar A.,Jung, Woo-Ok,Yoo, Minjin,Krische, Michael J.
supporting information, p. 18803 - 18807 (2019/11/19)
Highly enantioselective catalytic reductive coupling of allyl acetate with acetylenic ketones occurs in a chemoselective manner in the presence of aliphatic or aromatic ketones. This method was used to construct C14-C23 of pladienolide D in half the steps previously required.
BENZYL-, (PYRIDIN-3-YL)METHYL- OR (PYRIDIN-4-YL)METHYL-SUBSTITUTED OXADIAZOLOPYRIDINE DERIVATIVES AS GHRELIN O-ACYL TRANSFERASE (GOAT) INHIBITORS
-
, (2019/08/26)
The present invention relates to compounds of general formula (I), wherein the groups R1 and R2 are defined as in claim 1, which have valuable pharmacological properties, in particular bind to ghrelin O-acyl transferase (GOAT) and modulate its activity. The compounds are suitable for treatment and prevention of diseases which can be influenced by this receptor, such as metabolic diseases, in particular obesity.
Use of the 2-Pyridinesulfonyloxy Leaving Group for the Fast Copper-Catalyzed Coupling Reaction at Secondary Alkyl Carbons with Grignard Reagents
Shinohara, Riku,Morita, Masao,Ogawa, Narihito,Kobayashi, Yuichi
supporting information, p. 3247 - 3251 (2019/05/10)
Investigation of the copper-catalyzed coupling reaction of 2-pyridinesulfonates with Grignard reagents revealed that reactions with catalytic Cu(OTf)2 were completed in 40 min. The results differed from those of the previous CuI-catalyzed reactions of tosylates in the presence of additives (LiOMe and TMEDA) for 12-24 h. It was shown that the preferred coordination of the leaving group to the reagents accelerated the reaction. Successful reagents were MeMgCl and other RMgX. Complete inversion was established.
Palladium Catalysis for Aerobic Oxidation Systems Using Robust Metal–Organic Framework
Li, Jiawei,Liao, Jianhua,Ren, Yanwei,Liu, Chi,Yue, Chenglong,Lu, Jiaming,Jiang, Huanfeng
supporting information, p. 17148 - 17152 (2019/11/03)
Described here is a new and viable approach to achieve Pd catalysis for aerobic oxidation systems (AOSs) by circumventing problems associated with both the oxidation and the catalysis through an all-in-one strategy, employing a robust metal–organic framework (MOF). The rational assembly of a PdII catalyst, phenanthroline ligand, and CuII species (electron-transfer mediator) into a MOF facilitates the fast regeneration of the PdII active species, through an enhanced electron transfer from in situ generated Pd0 to CuII, and then CuI to O2, trapped in the framework, thus leading to a 10 times higher turnover number than that of the homogeneous counterpart for Pd-catalyzed desulfitative oxidative coupling reactions. Moreover, the MOF catalyst can be reused five times without losing activity. This work provides the first exploration of using a MOF as a promising platform for the development of Pd catalysis for AOSs with high efficiency, low catalyst loading, and reusability.
Copper-Catalyzed Oxidative Cleavage of Electron-Rich Olefins in Water at Room Temperature
Lippincott, Daniel J.,Trejo-Soto, Pedro J.,Gallou, Fabrice,Lipshutz, Bruce H.
supporting information, p. 5094 - 5097 (2018/09/13)
A copper-catalyzed oxidative cleavage of electron-rich olefins into their corresponding carbonyl derivatives is described as an alternative to ozonolysis. The scope includes various precursors to aryl ketone derivatives, as well as oxidations of enol ethers bearing atypical alkyl and dialkyl substitution, the first of their kind among such metal catalyzed alkene cleavage reactions. The use of an inexpensive copper salt, room temperature conditions, an aerobic atmosphere, and water as the global reaction medium highlight the green features of this new method. Associated mechanistic investigations are also presented.
Chiral isoxazolidine-mediated stereoselective umpolung α-phenylation of methyl ketones
Takeda, Norihiko,Furuishi, Mizuki,Nishijima, Yuri,Futaki, Erika,Ueda, Masafumi,Shinada, Tetsuro,Miyata, Okiko
supporting information, p. 8940 - 8943 (2018/12/10)
An effective asymmetric α-phenylation of methyl ketones with triphenylaluminium in the presence of (+)-benzopyranoisoxazolidine has been developed. The reaction proceeds via the in situ formation of a chiral N-alkoxyenamine and the subsequent diastereoselective nucleophilic phenylation to provide α-phenylated products in moderate to good yields, with high enantioselectivities.
Mild Chemoenzymatic Oxidation of Allylic sec-Alcohols. Application to Biocatalytic Stereoselective Redox Isomerizations
Martínez-Montero, Lía,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
, p. 2413 - 2419 (2018/03/13)
The design of catalytic oxidative methodologies in aqueous medium under mild reaction conditions and using molecular oxygen as final electron acceptor represents a suitable alternative to the traditional oxidative transformations. These methods are especially relevant if other functionalities that can be oxidized are present within the same molecule, as in the case of allylic alcohols. Herein we apply a simple chemoenzymatic system composed of the laccase from Trametes versicolor and 2,2,6,6-tetramethylpiperidinyloxy radical (TEMPO) to oxidize a series of racemic allylic sec-alcohols into the corresponding α,β-unsaturated ketones. Afterward, these compounds react with different commercially available ene-reductases to afford the corresponding saturated ketones. Remarkably, in the case of trisubstituted alkenes, the bioreduction reaction occurred with high stereoselectivity. Overall, a bienzymatic one-pot two-step sequential strategy has been described with respect to the synthesis of saturated ketones starting from racemic allylic alcohols, thus resembling the metal-catalyzed redox isomerizations of these derivatives that have been previously reported in the literature.
Hydrogen-transfer reduction of α,β-unsaturated carbonyl compounds catalyzed by naphthyridine-functionalized N-heterocyclic carbene complexes
Huang, Hsiao-Ching,Ramanathan, Mani,Liu, Yi-Hong,Peng, Shie-Ming,Liu, Shiuh-Tzung
, (2017/07/25)
Substitution of silver complex of 2-chloro-7-(mesitylimidazolylidenylmethyl)naphthyridine (NpNHC) with palladium(II), rhodium(I) and iridium(I) metal precursors provided [Pd(C,N-NpNHC)(η3-allyl)](BF4) (5), RhCl(COD)(C-NpNHC) (6a) and IrCl(COD)(C-NpNHC) (6b), respectively. Abstraction of chloride from 6a and 6b with AgBF4 provided the chelation complexes [Rh(COD)(C,N-NpNHC)](BF4) (7a) and Ir(COD)(C,N-NpNHC)(BF4) (7b), respectively. All complexes were characterized using NMR and elemental analyses and the structural details of 5 and 6a were further confirmed using X-ray crystallography. In catalytic activity studies, complex 5 was found to be an effective catalyst in the hydrogen-transfer reduction of α,β-unsaturated carbonyl compounds into the corresponding saturated carbonyl compounds.
Synthesis and neuroprotective evaluation of (E)-3,4-dihydroxystyryl p-substituted-phenethyl ketone derivatives against inflammatory and oxidative injury
Cheng, Can,Ning, Xianling,Luo, Yongming,Tian, Chao,Wang, Xiaowei,Guo, Ying,Liu, Junyi,Zhang, Zhili
, p. 1678 - 1685 (2016/07/30)
(E)-3,4-dihydroxystyryl p-substituted-phenethyl ketones and their 3,4-diacetylated derivatives were synthesized and examined their neuroprotective activities to further study the effect of p-substituents on the aromatic ring. The results revealed that steric hindrance effect of p-substituents has impact on neuroprotective activities against inflammatory and oxidative injury. Introduction of the bulkier groups are more beneficial to improve the neuroprotective activities than smaller groups. Compounds (4–5h, 4–5i and 4–5e) with p-substituted trifluoromethyl, isopropyl and t-butyl groups exhibited the best effects among all the target compounds.
