52497-01-5Relevant academic research and scientific papers
Superbase-Mediated Indirect Friedl?nder Reaction: A Transition Metal-Free Oxidative Annulation toward Functionalized Quinolines
Rahul,Nitha,Omanakuttan, Vishnu K.,Babu, Sheba Ann,Sasikumar,Praveen, Vakayil K.,Hopf, Henning,John, Jubi
, p. 3081 - 3089 (2020)
A superbase mediated indirect Friedl?nder reaction towards functionalized quinolines has been realized. The reaction was performed with o-aminobenzyl alcohol and ketones having an active methylene moiety in the presence of KOH and in DMSO. The reaction proceeds predominantly via initial formation of an imine intermediate and subsequent oxidation of the benzyl alcohol functionality and condensation to afford substituted quinolines. We could also demonstrate that a minor fraction of the reaction proceeds via a chalcone intermediate. The transition metal-free oxidative annulation was found to be general affording 2-substituted, 2,3-disubstituted/fused or multi-substituted quinolines. The reaction was extended towards the functionalization of natural products and the applicability of the reaction for gram-scale synthesis of quinolines was also demonstrated.
An Efficient Mesoporous Cu-Organic Nanorod for Friedl?nder Synthesis of Quinoline and Click Reactions
Elavarasan, Samaraj,Bhaumik, Asim,Sasidharan, Manickam
, p. 4340 - 4350 (2019/08/12)
Within the green chemistry context, heterogeneous catalysis for the synthesis of N-heterocycles from renewable resources using non-precious metals has garnered great interest in terms of economic and environmental perspectives. Herein, we present a triazine functional hierarchical mesoporous organic polymer (HMOP) with nanorod morphology together with large BET surface area ～1218 m2 g?1, huge pore volumeγτ“;6 mL g?1 and dual micro/mesopore architectures. Subsequent Cu-coordination with nitrogen atoms of the HMOP provides a robust catalyst (Cu-HMOP) to accomplish multi-step cascade reactions for preparation of N-heterocycles by different routes. For instance, the Cu-HMOP efficiently catalyzes one-pot sequential multi-step oxidative dehydrogenative coupling of 2-aminobenzyl alcohol with diverse aromatic ketones to afford corresponding quinolines in excellent isolated yields (up to 97 %). Secondly, the present catalyst exhibits good aerobic oxidative dehydrogenation activity of amines to imines. Thirdly, for “click” reaction involving azides-alkynes, the Cu-HMOP produced quantitative yield for 1,4-disubstituted 1,2,3-triazole derivatives at room temperature using water as solvent. Verification of active metal leaching by a hot filtration test as well as reusability of the retrieved Cu-HMOP catalysts shows a consistent activity in the multi-component quinoline synthesis as model reaction.
An unusual de-nitro reduction of 2-substituted-4-nitroquinolines
Zhou, Yu,Li, Jian,Liu, Hong,Zhao, Linxiang,Jiang, Hualiang
, p. 8511 - 8514 (2007/10/03)
The treatment of a variety of 2-substituted-4-nitroquinolines with Sn in the presence of concentrated hydrochloric acid in ethanol at 70 °C for 2-4 h afforded unusual de-nitro products 2-substituted-quinolines in good yields.
Incorporation of Quinoline-5,8-quinone Moiety into Polyaza Cavities
Thummel, Randolph P.,Chirayil, Sara,Hery, Christophe,Lim, Jean-Luc,Wang, Tie-Lin
, p. 1666 - 1671 (2007/10/02)
Silica gel supported nitric acid treatment of 2,5-dimethoxybenzaldehyde followed by reduction with iron powder provides 3,6-dimethoxy-2-aminobenzaldehyde.Friedlaender condensation of this species with a variety of ketones and diketones leads to 5,8-dimethoxyquinoline derivatives which may be oxidized by ceric ammonium nitrate (CAN) and pyridine-2,6-dicarboxylic acid N-oxide (PDANO) to the corresponding quinones.The quinone functionality can be incorporated into larger cavities by a selective stepwise Friedlaender approach and the CAN/PDANO oxidation appears to work preferentially for 5,8-dimethoxyquinoline.
