13533-27-2Relevant articles and documents
A new catalytic approach for aerobic oxidation of primary alcohols based on a Copper(I)-thiophene carbaldimines
Lagerspets, Emi,Valbonetti, Evelyn,Eronen, Aleksi,Repo, Timo
, (2021/06/03)
We report here novel Cu(I) thiophene carbaldimine catalysts for the selective aerobic oxidation of primary alcohols to their corresponding aldehydes and various diols to lactones or lactols. In the presence of the in situ generated Cu(I) species, a persistent radical (2,2,6,6-tetramethylpiperdine-N-oxyl (TEMPO)) and N-methylimidazole (NMI) as an auxiliary ligand, the reaction proceeds under aerobic conditions and at ambient temperature. Especially the catalytic system of 1-(thiophen-2-yl)-N-(4-(trifluoromethoxy)phenyl)methanimine (ligand L2) with copper(I)-iodide showed high reactivity for all kind of alcohols (benzylic, allylic and aliphatic). In the case of benzyl alcohol even 2.5 mol% of copper loading gave quantitative yield. Beside high activity under aerobic conditions, the catalysts ability to oxidize 1,5-pentadiol to the corresponding lactol (86% in 4 h) and N-phenyldiethanolamine to the corresponding morpholine derivate lactol (86% in 24 h) is particularly noteworthy.
Iron-Catalyzed Hydrogen Transfer Reduction of Nitroarenes with Alcohols: Synthesis of Imines and Aza Heterocycles
Wu, Jiajun,Darcel, Christophe
, p. 1023 - 1036 (2021/01/09)
A straightforward and selective reduction of nitroarenes with various alcohols was efficiently developed using an iron catalyst via a hydrogen transfer methodology. This protocol led specifically to imines in 30-91% yields, with a good functional group tolerance. Noticeably, starting from o-nitroaniline derivatives, in the presence of alcohols, benzimidazoles can be obtained in 64-72% yields when the reaction was performed with an additional oxidant, DDQ, and quinoxalines were prepared from 1,2-diols in 28-96% yields. This methodology, unprecedented at iron for imines, also provides a sustainable alternative for the preparation of quinoxalines and benzimidazoles.
Arene diruthenium(II)-mediated synthesis of imines from alcohols and amines under aerobic condition
Tamilthendral, Veerappan,Ramesh, Rengan,Malecki, Jan Grzegorz
, (2020/12/15)
The utility and selectivity of the newly synthesized dinuclear arene Ru(II) complex were demonstrated towards the synthesis of imines from coupling of alcohols and amines in the aerobic condition. Analytical and various spectral methods have been used to establish the unprecedented formation of the new thiolato-bridged dinuclear ruthenium complex. The molecular structure of the titled complex was evidenced with aid of X-ray crystallographic technique. A wide range of imines were obtained in good-to-excellent yields up to 98% and water as the by-product through an acceptorless dehydrogenative coupling of alcohols with amines. The catalytic reaction operated a concise atom economical without any oxidant with 1 mol% of the catalyst load. Further, the role of base, solvent and catalyst loading of the coupling reaction has been investigated. A plausible mechanism has been described and was found to proceed via the formation of an aldehyde intermediate. Short synthesis of antibacterial drug N-(salicylidene)-2-hydroxyaniline illustrated the utility of the present protocol.
Dearomative Photocatalytic Construction of Bridged 1,3-Diazepanes
Dixon, Darren J.,Duarte, Fernanda,Leitch, Jamie A.,Rogova, Tatiana
supporting information, p. 4121 - 4130 (2020/02/05)
The construction of diverse sp3-rich skeletal ring systems is of importance to drug discovery programmes and natural product synthesis. Herein, we report the photocatalytic construction of 2,7-diazabicyclo[3.2.1]octanes (bridged 1,3-diazepanes) via a reductive diversion of the Minisci reaction. The fused tricyclic product is proposed to form via radical addition to the C4 position of 4-substituted quinoline substrates, with subsequent Hantzsch ester-promoted reduction to a dihydropyridine intermediate which undergoes in situ two-electron ring closure to form the bridged diazepane architecture. A wide scope of N-arylimine and quinoline derivatives was demonstrated and good efficiency was observed in the construction of sterically congested all-carbon quaternary centers. Computational and experimental mechanistic studies provided insights into the reaction mechanism and observed regioselectivity/diastereoselectivity.
Non-Bonding Electron Pair versus π-Electrons in Solution Phase Halogen Bond Catalysis: Povarov Reaction of 2-Vinylindoles and Imines
Suzuki, Takumi,Kuwano, Satoru,Arai, Takayoshi
supporting information, p. 3208 - 3212 (2020/07/04)
The non-bonding electron pair (n-pair) of heteroatoms and π-electrons are both efficient halogen bond (XB) acceptors. In solid and gas phase studies, n-pairs generally prevail over π-bonding orbitals as XB acceptors, whereas few studies have been conducte
Enantioselective Direct anti-Selective Mannich-type Reactions Catalyzed by 3-Pyrrolidinecarboxylic Acid in the Presence of Potassium Carbonate: Addition of Potassium Carbonate Improves Enantioselectivities
Garg, Yuvraj,Tanaka, Fujie
supporting information, p. 4542 - 4546 (2020/06/08)
Mannich-type reactions of cyclohexanone and related six-membered-ring ketones with N-p-methoxyphenyl-protected imines of arylaldehydes catalyzed by 3-pyrrolidinecarboxylic acid in the presence of K2CO3 that afford anti-isomers of the Mannich products with
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
Novel N-Alkylbenzimidazole-Ruthenium (II) complexes: Synthesis and catalytic activity of N-alkylating reaction under solvent-free medium
?ahin, Neslihan,?zdemir, Nam?k,Gürbüz, Nevin,?zdemir, ?smail
, (2019/01/04)
In this article, direct N-alkylation reactions of amines with alcohols derivatives have been investigated. For this purpose, a new series ruthenium (II) complexes bearing N-coordinated benzimidazole complexes with have been synthesized and fully characterized by elemental analysis, FT-IR, 1H NMR and, 13C NMR spectroscopies. Additionally, the structures of the complexes 2b and 2c have been confirmed by X-ray crystallography. Although the N-alkylating reaction is usually performed in toluene, the catalytic study of complexes 2a-d has carried out no additional solvent and alcohol acted both as solvent and reactant of alkylating by using a little excess of alcohols. Surprisingly, conversion and selectivity of amine product for alkylation reaction have been seen high in medium solvent-free relative to in toluene.
Catalytic Asymmetric γ-Lactam Synthesis from Enolisable Anhydrides and Imines
Collar, Aarón Gutiérrez,Trujillo, Cristina,Lockett-Walters, Bruce,Twamley, Brendan,Connon, Stephen J.
, p. 7275 - 7279 (2019/05/15)
An anion-binding approach to the problem of preparing enantioenriched γ-lactams from enolisable anhydrides and imines is reported. A simple bisurea catalyst promotes the cycloaddition between α-aryl succinic anhydrides and either PMP- or benzhydryl-protec
Effect of new thiophene-derived aminophosphonic derivatives on growth of terrestrial plants. Part 2. Their ecotoxicological impact and phytotoxicity test toward herbicidal application in agriculture
Rogacz, Diana,Lewkowski, Jaros?aw,Malinowski, Zbigniew,Matusiak, Agnieszka,Morawska, Marta,Rychter, Piotr
, (2018/12/11)
Background: The aim of this work was to evaluate phytotoxicity of the thiophene derivatives against three persistent weeds of a high degree of resistance (Galinsoga parviflora Cav., Rumex acetosa L., and Chenopodium album) as well as their ecotoxicological impact on Heterocypris incongruens. In addition, Aliivibrio fischeri was measured. Two of eight described aminophosphonates, namely dimethyl N-(2-methoxyphenyl)amino(2-thienyl)methylphosphonate (2d) and dimethyl N-(tert-butyl)- (2-thienyl)methylphosphonate (2h), have never been reported before. Methods: The phytotoxicity of tested aminophosphonates toward their potential application as soil-applied herbicides was evaluated according to the OECD 208 Guideline. Ecotoxicological properties of investigated compounds were made using the OSTRACODTOXKITTM and Microtox tests. Results: Obtained results showed that four aminophosphonates have interesting herbicidal properties and N-(2-methylphenyl)amino- (2-thienyl)methylphosphonate (2a) was found to kill efficiently the most resistant plant Chenopodium album. None of the tested compounds showed important toxicity against Aliivibrio fischeri. However, their toxic impact on Heterocypris incongruens was significantly elevated. Conclusions: The aminophosphonate 2a showed herbicidal potential and it is not toxic against tested bacteria (EC50 over 1000 mg/L). It was found to be moderately toxic against ostracods [mortality 48% at 10 mg/kg of soil dry weight (s.d.w.)] and this problem should be solved by the use of the controlled release from a polymeric carrier.
