491-34-9Relevant articles and documents
Iron-Catalysed Direct Aromatic Amination with N-Chloroamines
Douglas, Gayle E.,Raw, Steven A.,Marsden, Stephen P.
, p. 5508 - 5514 (2019)
An optimized procedure for the direct intra- and intermolecular amination of aromatic C–H bonds with aminium radicals generated from N-chloroamines under iron catalysis is reported. A range of substituted tetrahydroquinolines could be readily prepared, while extension to the synthesis of benzomorpholines was more limited in scope. A direct one-pot variant was developed, allowing direct formal oxidative N–H/C–H coupling.
Reductive: N -methylation of quinolines with paraformaldehyde and H2 for sustainable synthesis of N -methyl tetrahydroquinolines
Wang, Hongli,Huang, Yongji,Jiang, Qi,Dai, Xingchao,Shi, Feng
, p. 3915 - 3918 (2019)
A new and straightforward method was developed for the synthesis of N-methyl-1,2,3,4-tetrahydroquinolines by one-pot reductive N-methylation of quinolines with paraformaldehyde and H2 over Pd/C catalyst. A series of functional MTHQs, including (±)-galipinine and (±)-angustrureine were successfully synthesized in good to excellent yields by applying this simple catalyst system.
Reduction of 1-Formyl-1,2,3,4-Tetrahydroquinoline with Ethyldiphenylsilane
Lukevits, E.,Zablotskaya, A.,Segal, I.
, p. 374 - 375 (1995)
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Photobehavior of mixed π*/ππ* triplets: Simultaneous detection of the two transients, solvent-dependent hydrogen abstraction, and reequilibration upon protein binding
Jornet, Dolors,Tormos, Rosa,Miranda, Miguel A.
, p. 10768 - 10774 (2011)
In the present work, a systematic study on hydrogen abstraction by the excited triplet states of 4-methoxybenzophenone (1) and 4,4′- dimethoxybenzophenone (2) from 1,4-cyclohexadiene (3), 4-methylphenol (4), 1,2,3,4-tetrahydroquinoline (5), and 1-methyl-1,2,3,4-tetrahydroquinoline (6) in different media has been undertaken. Laser flash photolysis (LFP) revealed that in nonpolar solvents, 1 and 2 triplets have a π* configuration with the typical benzophenone-like T-T absorption spectrum (?max ca. 525 nm). Conversely, in aqueous solution, transient absorption spectra with maxima at 450 and 680 nm, attributed to the ππ* triplet, were obtained. Quenching of 1 or 2 triplet by 3 led to ketyl radical formation with rate constants in the range of 106-108 M-1 s -1, being one order of magnitude higher in acetonitrile than in aqueous media. The rate constants of quenching by 4 and 5 were similar in both polar and nonpolar solvents; the highest value was found for 6 in acetonitrile ((6.3 to 6.9) - 109 M-1 s-1). For mechanistic insight, LFP of 1 or 2 in the presence of dimethoxybenzene as electron donor was performed. The results showed that in this case, triplet quenching is favored in aqueous solution. In addition, 2 included in human serum albumin (HSA) was submitted to LFP. The decay kinetics, monitored at 430 nm, fitted well with three lifetimes of 0.45, 1.4, and 14.4 ?s assignable to 2 in bulk solution and in site II or in site I of HSA, respectively. This assignment was confirmed by using oleic acid and ibuprofen as selective displacement probes.
Heterogeneous Hydrogenation of Quinoline Derivatives Effected by a Granular Cobalt Catalyst
Timelthaler, Daniel,Topf, Christoph
, (2021/11/22)
We communicate a convenient method for the pressure hydrogenation of quinolines in aqueous solution by using a particulate cobalt-based catalyst that is prepared in situ from simple Co(OAc)2 4H2O through reduction with abundant zinc powder. This catalytic protocol permits a brisk and atom-efficient access to a variety of 1,2,3,4-tetrahydroquinolines thereby relying solely on easy-to-handle reagents that are all readily obtained from commercial sources. Both the reaction setup assembly and the autoclave charging procedure are conducted on the bench outside an inert-gas-operated containment system, thus rendering the overall synthesis time-saving and operationally very simple.
Formic acid disproportionation into formaldehyde triggered by vanadium complexes with iridium catalysis under mild conditions inN-methylation
Guo, Yan-Jun,Li, Yang,Zhang, Ping,Zhao, Yu-Rou,Zhou, Chao-Zheng
supporting information, p. 2918 - 2924 (2021/05/05)
Formaldehyde (CH2O) has been used as a key platform reagent in the chemical industry for many decades. Currently, the industrial production of CH2O mainly depends on fossil resources, involving a highly energetic three-step process (200-1100 °C). Herein, we describe renewable formic acid (HCO2H) disproportionation into CH2O triggered by vanadium complexes with iridium catalysis under mild conditions at 30-50 °C inN-methylation. The gram-scale application ofin situgenerated CH2O by HCO2H disproportionation is demonstrated.
