1821-38-1Relevant articles and documents
Ruthenium(ii) complexes with N-heterocyclic carbene-phosphine ligands for theN-alkylation of amines with alcohols
Huang, Ming,Li, Yinwu,Lan, Xiao-Bing,Liu, Jiahao,Zhao, Cunyuan,Liu, Yan,Ke, Zhuofeng
supporting information, p. 3451 - 3461 (2021/05/03)
Metal hydride complexes are key intermediates forN-alkylation of amines with alcohols by the borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols and the hydrogenation of imines. Herein we report ruthenium(ii) complexes with hetero-bidentate N-heterocyclic carbene (NHC)-phosphine ligands, which realize smart pathway selection in theN-alkylated reactionviareactivity tuning of [Ru-H] species by hetero-bidentate ligands. In particular, complex6cbwith a phenyl wingtip group and BArF?counter anion, is shown to be one of the most efficient pre-catalysts for this transformation (temperature is as low as 70 °C, neat conditions and catalyst loading is as low as 0.25 mol%). A large variety of (hetero)aromatic amines and primary alcohols were efficiently converted into mono-N-alkylated amines in good to excellent isolated yields. Notably, aliphatic amines, challenging methanol and diamines could also be transformed into the desired products. Detailed control experiments and density functional theory (DFT) calculations provide insights to understand the mechanism and the smart pathway selectionvia[Ru-H] species in this process.
Ru-Catalyzed Selective Catalytic Methylation and Methylenation Reaction Employing Methanol as the C1 Source
Biswas, Nandita,Srimani, Dipankar
, p. 10544 - 10554 (2021/07/31)
Methanol can be employed as a green and sustainable methylating agent to form C-C and C-N bonds via borrowing hydrogen (BH) methodology. Herein we explored the activity of the acridine-derived SNS-Ru pincer for the activation of methanol to apply it as a C1 building block in different reactions. Our catalytic system shows great success toward the β-C(sp3)-methylation reaction of 2-phenylethanols to provide good to excellent yields of the methylated products. We investigated the mechanistic details, kinetic progress, and temperature-dependent product distribution, which revealed the slow and steady generation of in situ formed aldehyde, is the key factor to get the higher yield of the β-methylated product. To establish the environmental benefit of this reaction, green chemistry metrics are calculated. Furthermore, dimerization of 2-naphthol via methylene linkage and formation of N-methylation of amine are also described in this study, which offers a wide range of substrate scope with a good to excellent yield.
Improved and General Manganese-Catalyzed N-Methylation of Aromatic Amines Using Methanol
Neumann, Jacob,Elangovan, Saravanakumar,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
supporting information, p. 5410 - 5413 (2017/04/27)
A novel lutidine-based manganese PNP-pincer complex has been synthesized for the selective N-methylation of aromatic amines with methanol. Using borrowing hydrogen methodology, a selection of differently functionalized aniline derivatives is selectively methylated in good yields.
SILYLATION OF AROMATIC HETEROCYCLES BY EARTH ABUNDANT TRANSITION-METAL-FREE CATALYSTS
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Paragraph 0232, (2016/04/26)
The present invention describes chemical systems and methods for silylating aromatic organic substrates, said system or method comprising or consisting essentially of a mixture of (a) at least one organosilane and (b) at least one strong base, the definition of strong base now also including hydroxide, especially KOH, said system being preferably, but not necessarily substantially free of a transition-metal compound, and said methods comprising contacting a quantity of the organic substrate with a mixture of (a) at least one organosilane and (b) at least one strong base, under conditions sufficient to silylate the aromatic substrate; wherein said system is substantially free of a transition-metal compound.
Selective N,N-dimethylation of primary aromatic amines with methyl alkyl carbonates in the presence of phosphonium salts
Selva, Maurizio,Perosa, Alvise,Tundo, Pietro,Brunelli, Davide
, p. 5770 - 5773 (2007/10/03)
In the presence of onium salts, at 140-170 °C. methyl alkyl carbonates [1a-c, ROCO2Me, R = MeO(CH2)2[O(CH 2)2]n; n = 2-0, respectively] react with primary aromatic amines (XC6H4NH2, X = p-OMe, p-Me, H, p-Cl, p-CO2Me, o-Et, and 2,3-Me2C 6H3NH2) to yield the corresponding N,N-dimethyl derivatives (ArNMe2) with high selectivity (up to 96%) and good isolated yields (78-95%). Phosphonium salts (e.g., Ph3PEtI and n-Bu4PBr) are particularly efficient catalysts. Overall, a solvent-free reaction is coupled with safe methylating agents (1a-c) made from nontoxic dimethyl carbonate.
CARBON DIOXIDE: A REAGENT FOR THE SIMULTANEOUS PROTECTION OF NUCLEOPHILIC CENTERS AND THE ACTIVATION OF ALTERNATIVE LOCATIONS TO ELECTROPHILIC ATTACK. 16. A NOVEL SYNTHETIC METHOD FOR THE SIDE-CHAIN FUNCTIONALIZATION OF N-METHYL-o-TOLUIDINE AND FOR THE PREPARATION OF 2-SUBSTITUTED...
Katritzky, Alan R.,Fan, Wei-Qiang,Akutagawa, Kunihiko,Wang, Jin
, p. 407 - 414 (2007/10/02)
N-Methyl-o-toluidine is readily converted into a range of side-chain functionalized derivatives in a one-pot sequence, using carbon dioxide for N-protection.The intermediate lithium carbamate is further lithiated by butyllithium at the side-chain methyl group, and then reacted with an electrophile; the product undergoes acid-catalyzed decarboxylation during work-up. 2-Substituted N-methylindoles are produced when carboxylate esters are used as electrophiles.The yields are good, and no ring-substituted products are detected.
Chiral Building Blocks for the Synthesis of Nitrogen-Containing Natural Products, 5. The Enantioselective Synthesis of Optically Active, Benzene Nucleus-Substituted 1-Phenylethylamines from the Corresponding Acetophenones
Bringmann, Gerhard,Geisler, Joerg-Peter,Geuder, Torsten,Kuenkel, Georg,Kinzinger Lioba
, p. 795 - 805 (2007/10/02)
An efficient two-step procedure for the synthesis of enantiomerically pure, benzene nucleus-substituted 1-phenylethylamines 1 is described, with predictable absolute configuration at the stereogenic center: Imine formation from the substituted acetophenones 6 with (S)- or (R)-1-phenylethylamine and subsequent hydrogenation of the resulting Schiff bases 8 over Raney nickel leads to the secondary amines 9 and 10 in high diastereoselectivities.These dibenzylamines are cleaved regioselectively, usually next to the less substituted aromatic ring, giving the desired chiral 1-phenylethylamines 1 in high yields and enantiomeric purities.Scope and limitations of this new and facile approach to the versatile building blocks 1 are reported.
Synthesis of Indole Derivatives from N-Alkenyl-o-chloroanilines with Zero-valent Nickel Complex
Rodriguez, J. G.,Canoira, L.
, p. 883 - 888 (2007/10/02)
Reaction of N-alkenyl-o-chloroanilines in toluene with tetrakis(triphenylphosphine)nickel(0) was carried out mainly to give indole and indoline derivatives in good yields.A detailed analysis of the reaction products has been done and it allows us to confirm the postulated mechanism of the cyclization reaction.Torsional hindrance around C-C-Csp2 bond seems to prevent the cyclization reaction.
