- KOtBu-Catalyzed Michael Addition Reactions Under Mild and Solvent-Free Conditions
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Designed transition metal complexes predominantly catalyze Michael addition reactions. Inorganic and organic base-catalyzed Michael addition reactions have been reported. However, known base-catalyzed reactions suffer from the requirement of solvents, additives, high pressure and also side-reactions. Herein, we demonstrate a mild and environmentally friendly strategy of readily available KOtBu-catalyzed Michael addition reactions. This simple inorganic base efficiently catalyzes the Michael addition of underexplored acrylonitriles, esters and amides with (oxa-, aza-, and thia-) heteroatom nucleophiles. This catalytic process proceeds under solvent-free conditions and at room temperature. Notably, this protocol offers an easy operational procedure, broad substrate scope with excellent selectivity, reaction scalability and excellent TON (>9900). Preliminary mechanistic studies revealed that the reaction follows an ionic mechanism. Formal synthesis of promazine is demonstrated using this catalytic protocol.
- Thiyagarajan, Subramanian,Krishnakumar, Varadhan,Gunanathan, Chidambaram
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supporting information
p. 518 - 523
(2020/02/04)
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- Improved method used for preparing quinazoline drugs
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The invention relates to an improved method used for preparing quinazoline drugs, and provides a synthesis route taking 2-chloro-4-amino-6,7-dimethoxyquinazoline as an intermediate. The synthesis route comprises following steps: acrylonitrile and a methylamine alcohol solution are subjected to amination reaction so as to obtain intermediate (I); triethylamine is taken as an acid binding agent, andbenzyl chloride is taken as a protective group so as to obtain an intermediate (II); a metal hydride is adopted so as to obtain an intermediate (III) through reduction; acylation with tetrahydro-2-furancarbonylchloride is carried out so as to obtain an intermediate (IV); the intermediate (IV) and ammonium formate are subjected to hydrogenolysis under catalytic effect of palladium on carbon so asto obtain an intermediate (V); and at least condensation reaction with 2-chloro-4-amino-6,7-dimethoxyquinazoline is carried out so as to obtain quinazoline drug Alfuzosin Hydrochloride (VI). Comparedwith the prior art, the improved method possesses following advantages: operation is simple and safe; reaction conditions are convenient to control; energy consumption is low; yield is stable; and industrialized application prospect is promising.
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Paragraph 0032; 0036; 0043; 0046
(2018/07/06)
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- Synthesis, Characterization and Catalytic Application of MCM 41 Supported Phenanthrolinium Dibromide Catalyst for Aza-Michael Addition Reaction in Aqueous Medium
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Abstract: MCM-41 immobilized phenanthrolinium dibromide (phen-MCM-Br2) was easily prepared and applied as an efficient heterogeneous catalyst for aza-Michael addition of aromatic amines to α,β-unsaturated nitriles and nitro compounds in water. The catalyst was characterized by CHN, TGA, FT-IR, SEM, EDAX, XRD, BET, and TEM. It could be simply recovered and reused several times without significant loss of catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]
- Hosseinzadeh, Rahman,Aghili, Nora,Tajbakhsh, Mahmood
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p. 1194 - 1203
(2016/07/06)
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- C-F bond substitution via aziridinium ion intermediates
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Aliphatic 1,2-aminofluorides undergo extremely fast substitution reactions under the influence of lanthanum tris(hexamethyldisilazide). The substitution proceeds via an in situ generated aziridinium ion intermediate, which subsequently undergoes ring opening by addition of a nucleophile, yielding various β-substituted amines.
- Tr?ff,Janjetovic,Hilmersson
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p. 13260 - 13263
(2015/08/24)
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- Palladium nanoparticles in glycerol: A versatile catalytic system for C-X bond formation and hydrogenation processes
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Palladium nanoparticles stabilised by tris(3-sulfophenyl)phosphine trisodium salt in neat glycerol have been synthesised and fully characterised, starting from both Pd(II) and Pd(0) species. The versatility of this innovative catalytic colloidal solution has been proved by its efficient application in C-X bond formation processes (X=C, N, P, S) and C-C multiple bond hydrogenation reactions. The catalytic glycerol phase could be recycled more than ten times, preserving its activity and selectivity. The scope of each of these processes has demonstrated the power of the as-prepared catalyst, isolating the corresponding expected products in yields higher than 90%. The dual catalytic behaviour of this glycerol phase, associated to the metallic nanocatalysts used in wet medium (molecular- and surface-like behaviour), has allowed attractive applications in one-pot multi-step transformations catalysed by palladium, such as C-C coupling followed by hydrogenation, without isolation of intermediates using only one catalytic precursor. Copyright
- Chahdoura, Faouzi,Pradel, Christian,Gomez, Montserrat
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supporting information
p. 3648 - 3660
(2014/01/06)
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- Design, synthesis and biological evaluation of coumarin alkylamines as potent and selective dual binding site inhibitors of acetylcholinesterase
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Acetylcholinesterase inhibitors (AChEIs) are currently the drugs of choice, although only symptomatic and palliative, for the treatment of Alzheimer's disease (AD). Donepezil is one of most used AChEIs in AD therapy, acting as a dual binding site, reversi
- Catto, Marco,Pisani, Leonardo,Leonetti, Francesco,Nicolotti, Orazio,Pesce, Paolo,Stefanachi, Angela,Cellamare, Saverio,Carotti, Angelo
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p. 146 - 152
(2013/02/22)
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- Silicon tetrachloride catalyzed aza-michael addition of amines to conjugated alkenes under solvent-free conditions
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The efficient and very simple conjugate addition of aromatic and aliphatic amines to α,β-unsaturated carbonyl compounds under solvent-free conditions in the presence of catalytic amount of silicon tetrachloride is reported. The reaction of aryl and alkyl amines with different Michael acceptors gave the corresponding Michael adducts with simple catalyst and good to excellent yields. Georg Thieme Verlag Stuttgart New York.
- Azizi, Najmedin,Baghi, Roya,Ghafuri, Hossein,Bolourtchian, Mohammad,Hashemi, Mohammad
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experimental part
p. 379 - 382
(2010/04/03)
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- Imidazolium-based polymer supported gadolinium triflate as a heterogeneous recyclable Lewis acid catalyst for Michael additions
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A heterogeneous Lewis acid catalytic system has been developed by incorporating gadolinium triflate on to poly[styrene-co-(1-((4-vinylphenyl)methyl)-3-methylimidazolium) tetrafluoroborate] (1-Gd(OTf)3), and the catalytic activity of this system has been examined for Michael additions of amines and thiols to α,β-unsaturated esters and acrylonitrile. The reactions proceed in moderate to excellent yields in the presence of catalytic system 1-Gd(OTf)3. The catalytic system could be efficiently recycled and reused.
- Alleti, Ramesh,Oh, Woon Su,Perambuduru, Meher,Ramana,Prakash Reddy
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p. 3466 - 3470
(2008/09/21)
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- 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)-promoted efficient and versatile aza-Michael addition
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A convenient and versatile method was developed for aza-Michael addition using a substoichiometric amount of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Various nitrogen nucleophiles were efficiently introduced to α,β-unsaturated carbonyl compounds employing 0.5 equiv of DBU. Furthermore, other heteroatomic nucleophiles could also be introduced successfully under the same reaction conditions.
- Yeom, Chang-Eun,Kim, Mi Jeong,Kim, B. Moon
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p. 904 - 909
(2007/10/03)
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- Generation and reaction of benzylammonium N-methylides with N-cyanomethyl or N-(ethoxycarbonylalkyl) groups
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N-Cyanomethyl-, N-ethoxycarbonylmethyl- and N-(3-ethoxycarbonylpropyl)-N-methylbenzylammonium N-methylides 6a,b and 22 have been generated by fluoride ion-induced desilylation of the corresponding N-(trimethylsilylmethyl)benzylammonium salts 5a,b and 21. Sommelet-Hauser 7, 23 and Stevens 8, 24 rearrangement products were obtained from 6a and 22, but not from 6b.
- Zhang, Chen,Maeda, Yasuhiro,Shirai, Naohiro,Sato, Yoshiro
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- A structure-activity relationship study of novel phenylacetamides which are sodium channel blockers
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A structure-activity relationship study of a series of novel Na+ channel blockers, structurally related to N-[3-(2,6-dimethyl-1-piperidinyl)propyl]- α-phenylbenzeneacetamide (1, PD85639) is described. The diphenylacetic acid portion of the molecule was left unchanged throughout the study, while structural features in the amine portion and the amide alkyl linkage of the molecule were modified. The compounds were tested for inhibition of veratridine-stimulated Na+ influx in CHO cells expressing type IIA Na+ channels. Several derivatives show a trend toward more potent Na+ channel blockade activity with increasing lipophilicity of the amine portion of the molecule. The presence of a phenyl ring near the amine increases inhibitory potency. A three-carbon spacer between the amide and amine is optimal, and a secondary amide linkage is preferred.
- Roufos, Ioannis,Hays, Sheryl,Schwarz, Roy D.
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p. 1514 - 1520
(2007/10/03)
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- Cerium(IV) oxidations of β-aminoketones, VIII: Synthesis of 1,2,3,4-tetrahydroisoquinolines with differently substituted piperidine parts
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1- and 3-Alkyl- and/or aryl substituted tetrahydroisoquinolines are obtained by oxidative cyclisation of N-benzyl-β-aminoketones with cerium(IV) sulphate. In nearly all cases formation of mixtures of diastereomeres is observed. If the ketone function is r
- Holzgrabe,Inkman
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p. 209 - 215
(2007/10/02)
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