- Recyclable covalent triazine framework-supported iridium catalyst for the N-methylation of amines with methanol in the presence of carbonate
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An iridium complex Cp*Ir@CTF, which is synthesized by the coordinative immobilization of [Cp*IrCl2]2 on a functionalized covalent triazine framework (CTF), was found to be a general and highly efficient catalyst for the N-methylation of amines with methanol in the presence of carbonate. Under environmentally benign conditions, a variety of desirable products were obtained in high yields with complete selectivities and functional group friendliness. Furthermore, the synthesized catalyst could be recycled by simple filtration without obvious loss of catalytic activity after sixth cycle. Notably, this research exhibited the potential of covalent triazine framework-supported transition metal catalysts for hydrogen autotransfer process.
- Liu, Peng,Yang, Jiazhi,Ai, Yao,Hao, Shushu,Chen, Xiaozhong,Li, Feng
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p. 281 - 290
(2021/03/26)
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- Fast continuous alcohol amination employing a hydrogen borrowing protocol
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A continuous flow method for the direct conversion of alcohols to amines via a hydrogen borrowing approach is reported. The method utilises a low loading (0.5%) of a commercial catalyst system ([Ru(p-cymene)Cl2]2 and DPEPhos), reagent grade solvent and is selective for primary alcohols. Successful methylation of amines using methanol and the direct dimethylamination of alcohols using commercial dimethylamine solution are reported. The synthesis of two pharmaceutical agents Piribedil (5) and Buspirone (25) were accomplished in good yields employing these new methods.
- Labes, Ricardo,Mateos, Carlos,Battilocchio, Claudio,Chen, Yiding,Dingwall, Paul,Cumming, Graham R.,Rincón, Juan A.,Nieves-Remacha, Maria José,Ley, Steven V.
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supporting information
p. 59 - 63
(2019/01/11)
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- Selective monomethylation of anilines by Cu(OAc)2-promoted cross-coupling with MeB(OH)2
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N-Methylanilines are readily synthesized in high yields through the copper(ll)-promoted coupling of anilines and methylboronic acid. This method represents a new approach for the selective monomethylation of anilines, and it is the first reported example
- Gonzalez, Israel,Mosquera, Jesus,Guerrero, Cesar,Rodriguez, Ramon,Cruces, Jacobo
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supporting information; experimental part
p. 1677 - 1680
(2009/09/06)
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- Structures of reactive nitrenium ions: Time-resolved infrared laser flash photolysis and computational studies of substituted N-methyl-N-arylnitrenium ions
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A series of para-substituted N-methyl-N-phenylnitrenium ions (N-(4-biphenylyl)-N-methylnitrenium ion, N-(4-chlorophenyl)-N-methylnitrenium ion, N-(4-methoxyphenyl)-N-methylnitrenium ion, and N-(4-methylphenyl)-N-methylnitrenium ion) were generated through photolysis of the appropriately substituted 1-aminopyridinium salt. Laser flash photolysis using UV - vis detection as well as photoproduct analysis verified that the expected nitrenium ions were formed cleanly and rapidly following photolysis. Laser flash photolysis with time-resolved infrared detection allowed for structural characterization of the nitrenium ions through observation of a symmetrical aromatic C=C stretch in the region 1580-1628 cm-1. The specific frequencies reflect the degree of quinoidal character present in each phenylnitrenium ion (i.e., the degree to which the nitrenium ion resembles a 4-iminocyclohexa-2,5-dienyl cation). The 4-methoxy derivative shows the highest frequency C=C stretch, indicating that this strongly π-electron-donating substituent imparts more quinoidal character, and the 4-chloro derivative shows the lowest frequency C=C stretch, suggesting that it possesses the least quinoidal character. Quantum calculations using density functional theory (BPW91/cc-pVDZ) were carried out on the same nitrenium ions. The theoretically derived IR frequencies showed excellent quantitative agreement with the experiment. The computed structures show significant bond length alternation in the phenyl rings, shortened C-N bond lengths, and substantial positive charge delocalization into the phenyl rings. All of these effects are more pronounced with increasing π-donating character of the ring substituent. Arylnitrenium ions are well described as 4-iminocyclohexa-2,5-dienyl cations.
- Srivastava, Sanjay,Ruane, Patrick H.,Toscano, John P.,Sullivan, Michael B.,Cramer, Christopher J.,Chiapperino, Dominic,Reed, Elizabeth C.,Falvey, Daniel E.
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p. 8271 - 8278
(2007/10/03)
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- A convenient one pot procedure for N-methylation of aromatic amines using trimethyl orthoformate
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Aromatic amines react with trimethyl orthoformate in the presence of concentrated sulfuric acid followed by acid hydrolysis to afford mono methylated amines in moderate to good yields.
- Padmanabhan, Seetharamaiyer,Reddy, N. Laxma,Durant, Graham J.
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p. 691 - 699
(2007/10/03)
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- A HIGHLY EFFICIENT AND GENERAL N-MONOMETHYLATION OF FUNCTIONALIZED PRIMARY AMINES VIA FORMYLATION -- BORANE:METHYL SULFIDE REDUCTION
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Formylation of functionalized primary aromatic and aliphatic amines with acetic formic anhydride (AFA) followed by borane:methyl sulfide reduction in the same pot affords the corresponding N-methylamines in excellent isolated yields, uncontaminated by bis alkylation; the reaction sequence is applicable to even very weakly basic and sterically hindered amines.
- Krishnamurthy, S.
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p. 3315 - 3318
(2007/10/02)
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