2905-56-8Relevant articles and documents
The scale-up of continuous biphasic liquid/liquid reactions under super-heating conditions: Methodology and reactor design
Mandrelli, Francesca,Buco, Alessia,Piccioni, Lorenzo,Renner, Florian,Guelat, Bertrand,Martin, Benjamin,Schenkel, Berthold,Venturoni, Francesco
, p. 1425 - 1430 (2017)
Biphasic liquid/liquid reactions are commonplace, however their scale-up under super-heating conditions is not. Even more challenging efforts have to be expected in the case of a large scale continuous production process, which also includes the development at a lab scale, the selection and design of the continuous reaction equipment. However, by running chemistry above the boiling point of the solvent, the solvent selection can be widened to include green solvents and continuous processing guarantees a limited and safe footprint. Herein is reported a systematic methodology for the development and scale-up of a biphasic reaction under super-heating conditions, as well as the design of a continuous reactor column suitable for handling such conditions. Taking the alkylation of benzylamine with 1,5-dibromopentane as a model reaction, kinetic determination and fluid dynamic characterization of the biphasic media have been instrumental for a successful scale-up concept which was proven in a custom-made hastelloy reactor column.
NUCLEOPHILIC DISPLACEMENT OF N-BENZYL GROUPS: EFFECT OF PYRIDINIUM ON RATES AND MECHANISM
Katritzky, Alan R.,Musumarra, Giuseppe,Sakizadeh, Kumars
, p. 2701 - 2703 (1980)
Steric acceleration by α-substituents in pyridine leaving groups is quantitatively assessed.Constraint of α-phenyls to near planarity forms superior leaving groups for SN2 displacements. α-t-Butyl groups significantly increase SN1 dissociation.
Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
Bera, Jitendra K.,Pandey, Pragati
, p. 9204 - 9207 (2021/09/20)
A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
Method for catalyzing hydrodesulfurization of thioamide derivative
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Paragraph 0019-0023, (2021/07/09)
The invention provides a method for catalyzing hydrodesulfurization of a thioamide derivative, which comprises the following steps: sequentially adding a pentacarbonyl manganese bromide catalyst, a reaction substrate thioamide derivative, Lewis acid, a solvent and alkali into a polytetrafluoroethylene lined reaction tube, putting the reaction tube into a high-pressure kettle, introducing hydrogen to carry out catalytic hydrogenation reaction, cooling to room temperature, discharging gas, washing the reaction tube with ethyl acetate, passing through a silica gel small short column, carrying out spin drying, and carrying out column chromatography purification to obtain a target product. The monovalent manganese which is low in toxicity and good in chemical selectivity and biocompatibility is used as the catalyst to catalyze hydrodesulfurization of the thioamide derivative, the substrate range is wide, the yield of amine is high, and the method has high drug synthesis application value.
Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
supporting information, p. 5022 - 5037 (2021/05/04)
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
Direct: N -alkylation of sulfur-containing amines
Li, Chen,Ge, Min-Tong,Bai, Liang,Xia, Ai-Bao,Xu, Dan-Qian,Xu, Zhen-Yuan
supporting information, p. 4478 - 4482 (2021/05/31)
An efficient ruthenium-catalyzed method has been developed for the direct N-alkylation of sulfur-containing amines with alcohols, for the first time, by a step-economical and environmentally friendly hydrogen borrowing strategy. The present methodology features base-free conditions and broad substrate scope, with water being the only by-product. Moreover, this protocol has been applied to the synthesis of the pharmaceutical drug Quetiapine.
Iridium and bis(4-nitrophenyl)phosphoric acid catalysed amination of diol by hydrogen-borrowing methodology for the synthesis of cyclic amine: Synthesis of clopidogrel
Swain, Sharada Prasanna,Shri, Om,Ravichandiran
, (2021/05/13)
The borrowing hydrogen method is an environmentally benign process for the synthesis of amines, as H2O is the side product. A new green process for the amination of diol by [Ir] catalyst 15 and bis(4-nitrophenyl)phosphoric acid for the synthesis of cyclic amine is reported. This method was successfully applied for the synthesis of antiplatelet drug clopidogrel.
Hydrosilane-Mediated Electrochemical Reduction of Amides
Okamoto, Kazuhiro,Nagahara, Shingo,Imada, Yasushi,Narita, Risako,Kitano, Yoshikazu,Chiba, Kazuhiro
, p. 15992 - 16000 (2021/07/20)
Electrochemical reduction of amides was achieved by using a hydrosilane without any toxic or expensive metals. The key reactive ketyl radical intermediate was generated by cathodic reduction. Continuous reaction with anodically generated silyl radicals or zinc bromide resulted in chemoselective deoxygenation to give the corresponding amines.
Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
, p. 2059 - 2067 (2021/09/02)
Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
Lithium compound catalyzed deoxygenative hydroboration of primary, secondary and tertiary amides
Bisai, Milan Kumar,Gour, Kritika,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
supporting information, p. 2354 - 2358 (2021/03/03)
A selective and efficient route for the deoxygenative reduction of primary to tertiary amides to corresponding amines has been achieved with pinacolborane (HBpin) using simple and readily accessible 2,6-di-tert-butyl phenolate lithium·THF (1a) as a catalyst. Both experimental and DFT studies provide mechanistic insight. This journal is
