40571-86-6Relevant academic research and scientific papers
Syntheses, structures and catalytic activities of low-coordinated rare-earth metal complexes containing 2,2′-pyridylpyrrolides
Du, Jun,Zhou, Shuangliu,Zhang, Xiuli,Zhang, Lijun,Cui, Peng,Huang, Zeming,Wei, Yun,Zhu, Xiancui,Wang, Shaowu
, (2019/11/20)
Reactions of the ligand precursors 2-(2′-pyridyl)-3,5-Me2-pyrrole (L1H) and 2-(2-pyridyl)-3,4,5-Me3-pyrrole (L2H) with [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 in toluene afforded a series of low-coordinated rare-earth metal bis-amido complexes L1RE[N(SiMe3)2]2 [RE = Y (1a), Dy (1b), Er (1c), Yb (1d)] and L2RE[N(SiMe3)2]2 [RE = Y (2a), Dy (2b), Er (2c), Yb (2d)]. With the ionic radius of rare-earth metal increasing, the reaction of L1H and [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 gave dinuclear complexes (L1)2RE(μ-Cl)(μ-η5:η1:η1-L1)RE(L1)[N(SiMe3)2]2 [RE = Sm (1e), Pr (1f)]; however, the reaction of L2H and [(Me3Si)2N]3Sm(μ-Cl)Li(THF)3 afforded (L2)2Sm[N(SiMe3)2]2 (2e). Results indicated that the ionic radius of rare-earth metal and subtle change in the ligands have substantial effects on the structure and bonding mode of complexes. The complexes showed a high catalytic activity for the ring-opening reaction of cyclohexene oxide with amines to afford various β-aminoalcohols under mild solvent-free conditions.
Asymmetric amination of meso-epoxide with vegetable powder as a low-toxicity catalyst
Asano, Tatsuhiro,Kurata, Hiroyuki,Takeuchi, Yuki,Tsuzaki, Kazuya,Wada, Koichi
, (2020/08/11)
This paper describes the scope and limitation of substrates subjected to asymmetric amination with epoxides catalyzed by a soluble soybean polysaccharide (Soyafibe S-DN), which we recently discovered from the reaction of 1,2-epoxycyclohexane with cyclopropylamine. Various meso-epoxides reacted with various amines afforded the corresponding products with good enantiomeric selectivity. Since it was found that pectin was found to have a catalytic ability after screening commercially available polysaccharides, we studied 33 different vegetable powders having pectic substances, and we found that many vegetable powders showed catalytic ability. These results should guide in using vegetable components as low-toxic catalysts for the production of pharmaceuticals.
Microwave-Assisted CuCl-Catalyzed Three-Component Reactions of Alkynes, Aldehydes, and Amino Alcohols
Chen, Ning,Li, Xiang,Xu, Jiaxi
supporting information, p. 3336 - 3344 (2019/08/28)
A microwave (MW)-assisted three-component coupling of amino alcohols, aldehydes, and alkynes is developed under catalysis by CuCl. Compared with thermal conditions, MW irradiation greatly increases the reaction efficiency. The reactions of various primary N -alkyl/arylamino alcohols, aliphatic/aromatic aldehydes, and alkynes are systematically investigated, affording the desired products in moderate to good yields. Notably, acetylene is also an effective reactant under the current MW-assisted conditions.
Broadening the chemical scope of laccases: Selective deprotection of N-benzyl groups
Martínez-Montero, Lía,Díaz-Rodríguez, Alba,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
supporting information, p. 2794 - 2798 (2015/05/27)
Laccase from Trametes versicolor together with TEMPO has been found to be a very efficient system to deprotect N-benzylated primary amines, differing from previously described methods since it uses oxygen as a mild oxidant in aqueous medium. Chemoselective removal of the benzyl group was achieved with excellent yields when secondary amines and alcohol moieties were also present.
An improved and efficient process for the scalable preparation of optically pure trans-2-aminocyclohexanols
Xue, Feng,Li, Chang-Gong,Zhu, Yong,Lou, Tian-Jun
, p. 322 - 324 (2014/06/09)
An improved and efficient process has been developed for a green and scalable preparation of optically pure (1R,2R) - and (1S,2S) -trans-2-aminocyclohexanols. The process utilised hot water to promote the aminolysis of cyclohexene oxide by benzylamine to afford racemic trans-2-(benzylamino)cyclohexanols, which were resolved by sequential and repeated use of (R)- and (S)-mandelic acid. Finally, after treatment of the two salts sequentially with HCl and NaOH and recovery of mandelic acid, liberation was achieved of the optically pure trans-2-benzylaminoaminocyclohexanols which were smoothly debenzylated using a low loading of a Pd/C catalyst to the trans-2-aminocyclohexanols. The synthetic route has been successfully applied to large-scale (1 mol) preparations in good yield.
N-Fluorobenzenaminium tetrafluoroborate generated in situ by aniline and Selectfluor as a reusable catalyst for the ring opening of epoxides with amines under microwave irradiation
Chauhan, Manmohan Singh,Yadav, Geeta Devi,Hussain, Firasat,Singh, Surendra
, p. 3945 - 3952 (2015/02/19)
The ring opening of epoxides with aromatic and aliphatic amines was carried out under solvent free conditions using N-fluorobenzenaminium tetrafluoroborate (2 mol%) generated in situ by the reaction of aniline and Selectfluor as a catalyst with microwave irradiation. Excellent yields of β-amino alcohols were obtained. The catalyst also results in the retention of the stereochemistry for the ring opening of enantiopure epoxide with amine. The catalyst was recovered and reused up to 4 cycles for the ring opening of cyclohexene oxide with aniline. This journal is
CYCLOHEXANEDIAMINE COMPOUNDS AND METHODS FOR THEIR PREPARATION
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Paragraph 0104; 0105, (2014/10/04)
The present invention provides processes for the preparation of cyclohexanediamine compounds of formula Ia and intermediates thereof. The compounds are useful as Syk kinase inhibitors and in various pharmaceutical compositions, and particularly useful for treating conditions mediated at least in part by Syk kinase activity.
Synthesis of (3RS,3aSR,8aSR)-3-phenyloctahydrocyclohepta[b]pyrrol-4(1H)-one via the aza-Cope-Mannich rearrangement
Belov, Dmitry S.,Lukyanenko, Evgeny R.,Kurkin, Alexander V.,Yurovskaya, Marina A.
scheme or table, p. 9214 - 9218 (2011/12/01)
A convenient and scalable method for the preparation of (3RS,3aSR,8aSR)-phenyloctahydrocyclohepta[b]pyrrol-4(1H)-one based on the aza-Cope-Mannich rearrangement is described. This approach allows us to synthesize the target compound in nine steps in a high overall yield (42%) with complete stereocontrol and up to 100 g scale.
Zinc tetrafluoroborate hydrate as a mild catalyst for epoxide ring opening with amines: Scope and limitations of metal tetrafluoroborates and applications in the synthesis of antihypertensive drugs (RS)/(R)/(S)-metoprolols
Pujala, Brahmam,Rana, Shivani,Chakraborti, Asit K.
experimental part, p. 8768 - 8780 (2011/12/04)
The scope and limitations of metal tetrafluoroborates have been studied for epoxide ring-opening reaction with amines, and Zn(BF4) 2?xH2O has been found to be a mild and efficient catalyst affording high yields under solvent-free conditions at rt with excellent chemo-, regio-, and stereoselectivities. The catalytic efficiency followed the order Zn(BF4)2?xH2O ? Cu(BF4)2?xH2O > Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > LiBF4 for reactions with cyclohexene oxide and Zn(BF4)2?xH2O ? Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > Cu(BF4)2?xH2O for stilbene oxide, but AgBF4 was ineffective. For reaction of styrene oxide with aniline, the metal tetrafluoroborates exhibited comparable regioselectivity (1:99-7:93) with preferential reaction at the benzylic carbon of the epoxide ring. A reversal of regioselectivity (91:1-69:31) in favor of the reaction at the terminal carbon of the epoxide ring was observed for reaction with morpholine. The regioselectivity was dependent on the electronic and steric factors of the epoxide and the pKa of the amine and independent of amine nucleophilicity. The role of the metal tetrafluoroborates is envisaged as "electrophile nucleophile dual activation" through cooperativity of coordination, charge-charge interaction, and hydrogen-bond formation that rationalizes the catalytic efficiency, substrate reactivity, and regioselectivity. The methodology was used for synthesis of cardiovascular drug metoprolol as racemic and enriched enantiomeric forms.
Thieme chemistry journal awardees-where are they now? bifunctional organocatalysis with N-Formyl-l-proline: A novel approach to epoxide ring opening and sulfide oxidation
Wei, Shengwei,Stingl, Kerstin A.,Wei?, Katharina M.,Tsogoeva, Svetlana B.
experimental part, p. 707 - 711 (2010/06/13)
A conceptually distinct approach to the aminolysis of 1,2-epoxides, which involves Lewis base-Br?nsted acid catalysis employing N-formyl-l-proline as an easily accessible bifunctional organocatalyst and water as a solvent is presented. The potential of N-formyl-l-proline as organocatalyst for the sulfide oxidation reaction using aqueous hydrogen peroxide as environmentally benign and readily available oxidant is also demonstrated. Good to high yields are achieved for both reactions. Georg Thieme Verlag Stuttgart ? New York.
