- Rapid Multialkylation of Aqueous Ammonia with Alcohols by Heterogeneous Iridium Catalyst under Simple Conditions
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This paper reports the synthesis of tertiary and secondary amines from aqueous ammonia and benzylic alcohols by titania-supported iridium catalyst. It is a successful example of heterogeneous systems at moderate temperature without either additional solvent or high pressure. The catalytic system showed good tolerance to the atmosphere condition and performed rapidly to give tribenzylamine a yield of over 99 % within 6 hours in argon. The crystal structure of titania supports for iridium catalysts strongly affected their activity. The catalysis smoothly proceeded on larger scales. The catalyst could be easily reused and run at least for 5 cycles without significant loss of activity. The highly-dispersed iridium species of less than 2 nm in diameter would be responsible for the excellent catalytic activity. This catalyst is well applicable in multialkylation of aqueous ammonia with various primary and secondary benzylic alcohols.
- Yu, Han,Ma, Lin,Wada, Kenji,Kurihara, Ryohsuke,Feng, Qi,Uemura, Shinobu,Isoda, Kyosuke
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p. 3588 - 3593
(2021/07/02)
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- Dichotomy of Atom-Economical Hydrogen-Free Reductive Amidation vs Exhaustive Reductive Amination
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Rh-catalyzed one-step reductive amidation of aldehydes has been developed. The protocol does not require an external hydrogen source and employs carbon monoxide as a deoxygenative agent. The direction of the reaction can be altered simply by changing the solvent: reaction in THF leads to amides, whereas methanol favors formation of tertiary amines.
- Kolesnikov, Pavel N.,Usanov, Dmitry L.,Muratov, Karim M.,Chusov, Denis
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supporting information
p. 5657 - 5660
(2017/10/25)
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- Tris(8-methoxy-2-quinolylmethyl)amine (8-MeOTQA) as a highly fluorescent Zn2+ probe prepared by convenient C3-symmetric tripodal amine synthesis
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A convenient synthesis of C3-symmetric tribenzylamine (TBA) derivatives has been investigated. The reaction of benzyl chlorides with acetaldehyde ammonia trimer (1) in the presence of base afforded tribenzylamines in high yields. This efficient method allows the diverse synthesis of TPA (tris(2-pyridylmethyl)amine) and TQA (tris(2-quinolylmethyl)amine) derivatives. Among the TQA compounds prepared, tris(8-methoxy-2-quinolylmethyl)amine (8-MeOTQA, 4) exhibited superior properties as a fluorescent zinc probe with high quantum yield (Zn = 0.51) and high sensitivity (limit of detection (LOD) = 3.4 nM). The X-ray crystallographic analysis of [Zn(8-MeOTQA)]2+ revealed that the steric and electronic effect of 8-methoxy substituents kicks out the solvent and counterion molecules from the metal coordination sphere, resulting in short Zn-Nquinoline coordination distances (2.04-2.07 ?). The pseudo hexacoordinate complex of 6-methoxy derivative, [Zn(6-MeOTQA)(DMF)(ClO4)]+, exhibited longer Zn-Nquinoline distances (2.07-2.19 ?) and much smaller fluorescence intensity (Zn = 0.027). The replacement of one of the three 8-methoxyquinolines with pyridine also afforded much less fluorescent zinc complex (Zn = 0.095) due to the solvent coordination (Zn-Nquinoline = 2.05-2.18 ? for [Zn(8-MeOBQPA)(CH3OH)]2+).
- Mikata, Yuji,Nodomi, Yuki,Ohnishi, Risa,Kizu, Asako,Konno, Hideo
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p. 8021 - 8030
(2015/05/13)
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- Highly efficient heterogeneous gold-catalyzed direct synthesis of tertiary and secondary amines from alcohols and urea
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Urea, the white gold: The efficient synthesis of tertiary and secondary amines is achieved by heterogeneous gold-catalyzed direct amination of stoichiometric alcohols with urea in good to excellent yields. Via a hydrogen autotransfer pathway, the reactions of primary alcohols with urea give tertiary amines exclusively, while secondary alcohols selectively afford secondary amines.
- He, Lin,Qian, Yue,Ding, Ran-Sheng,Liu, Yong-Mei,He, He-Yong,Fan, Kang-Nian,Cao, Yong
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experimental part
p. 621 - 624
(2012/05/20)
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- Ruthenium-catalyzed formation of tertiary amines from nitriles and alcohols
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A ruthenium-catalyzed tertiary-amine formation was developed using the borrowing hydrogen strategy. Various tertiary amines were obtained efficiently from nitriles and primary alcohols. Two possible pathways were found for the tertiaryamine formation under RuCl3/dppf catalytic conditions. The nitriles mainly act as a nitrogen source in this kind of transformation.
- Liu, Saiwen,Chen, Ru,Deng, Guo-Jun
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supporting information; experimental part
p. 489 - 491
(2011/06/25)
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- The "borrowing hydrogen strategy" by supported ruthenium hydroxide catalysts: Synthetic scope of symmetrically and unsymmetrically substituted amines
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The N-alkylation of ammonia (or its surrogates, such as urea, NH 4HCO3, and (NH4)2CO3) and amines with alcohols, including primary and secondary alcohols, was efficiently promoted under anaerobic conditions by the easily prepared and inexpensive supported ruthenium hydroxide catalyst Ru(OH)x/TiO2. Various types of symmetrically and unsymmetrically substituted "tertiary" amines could be synthesized by the N-alkylation of ammonia (or its surrogates) and amines with "primary" alcohols. On the other hand, the N-alkylation of ammonia surrogates (i.e., urea and NH 2HCO3) with "secondary" alcohols selectively produced the corresponding symmetrically substituted "secondary" amines, even in the presence of excess amounts of alcohols, which is likely due to the steric hindrance of the secondary alcohols and/or secondary amines produced. Under aerobic conditions, nitriles could be synthesized directly from alcohols and ammonia surrogates . The observed catalysis for the present N-alkylation recations was intrinsically heterogeneous, and the retrieved catalyst could be reused without any significant loss of catalytic performance. The present catalytic transformation would proceed through consecutive N-alkylation reactions, in which alcohols act as alkylating reagents. On the basis of deuterium-labeling experiments, the formation of the ruthenium dihydride species is suggested during the N-alkylation reactions.
- Yamaguchi, Kazuya,He, Jinling,Oishi, Takamichi,Mizuno, Noritaka
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scheme or table
p. 7199 - 7207
(2010/09/05)
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- Process for reductively aminating ketones and aldehydes with aqueous amines and catalysts suitable therefor
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A process for preparing amines of the general formula (I)[in-line-formulae]R1R2CHNR3R4??(I)[/in-line-formulae]in which R1, R2, R3 and R4 are each independently hydrogen, straight-chain or branched, halogenated or halogen-free C1-C12-alkyl, C3-C12-cycloalkyl, C6-C10-aryl or C7-C11-aralkyl, by catalytic, hydrogenating amination of carbonyl compounds of the general formula (II)[in-line-formulae]R1—C(═O)—R2??(II)[/in-line-formulae]with nitrogen compounds of the general formula (III)[in-line-formulae]HNR3R4??(III)[/in-line-formulae]in the presence of bifunctional catalyst systems comprising a.) a hydrogenation-active catalyst component comprising one or more metals of transition group 8 of the Periodic Table and b.) one or more solid, acidic cocatalysts, wherein the hydrogenating amination is carried out in the presence of aqueous ammonia or aqueous amine of the formula (III) and at least one organic solvent miscible with ammonia or the aqueous amine of the formula (III).
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Page/Page column 2
(2008/06/13)
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