- A nickel catalyzed acceptorless dehydrogenative approach to quinolines
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A general, efficient and environmentally benign, one-step synthesis of substituted quinoline derivatives was achieved by acceptorless dehydrogenative coupling of o-aminobenzylalcohols with ketones and secondary alcohols catalyzed by a cheap, earth abundant and easy to prepare nickel catalyst [Ni(MeTAA)], featuring a tetraaza macrocyclic ligand (tetramethyltetraaza[14]annulene (MeTAA)). A wide variety of substituted quinolines were synthesized in high yields starting from readily available o-aminobenzylalcohols and ketones or secondary alcohols. A few controlled reactions were carried out to establish the acceptorless dehydrogenative nature of the reactions.
- Parua, Seuli,Sikari, Rina,Sinha, Suman,Das, Siuli,Chakraborty, Gargi,Paul, Nanda D.
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- Efficient Organoruthenium Catalysts for α-Alkylation of Ketones and Amide with Alcohols: Synthesis of Quinolines via Hydrogen Borrowing Strategy and their Mechanistic Studies
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A new family of phosphine free organometallic ruthenium(II) catalysts (Ru1–Ru4) supported by bidentate NN Schiff base ligands (L1–L4 where L1=N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazineylidene)methyl) aniline, L2=N,N-diethyl-4-((2-phenyl-2-(pyridin-2-ylmethyl)hydrazineylidene)methyl)aniline, L3=N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-yl)hydrazineylidene)methyl)- aniline and L4=N,N-diethyl-4-((2-phenyl-2-(pyridin-2-yl)hydrazineylidene)methyl) aniline) was prepared and characterized. These half-sandwich complexes acted as catalysts for C?C bond formation and exhibited excellent performance in the dehydrogenative coupling of ketones and amides. In the synthesis of C–C bonds, alcohols were utilized as the alkylating agent. A broad range of substrates, including sterically hindered ketones and alcohols, were well tolerated under the optimized conditions (TON up to 47000 and TOF up to 11750 h?1). This ruthenium (II) catalysts were also active towards the dehydrogenative cyclization of o-amino benzyl alcohol for the formation of quinolines derivatives. Various polysubstituted quinolines were synthesized in moderate to excellent yields (TON up to 71000 and TOF up to 11830 h?1). Control experiments were carried out and the ruthenium hydride intermediate was characterized to support the reaction mechanism and a probable reaction pathway of dehydrogenative coupling for the C?C bond formation has been proposed.
- Maji, Ankur,Singh, Anshu,Singh, Neetu,Ghosh, Kaushik
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p. 3108 - 3125
(2020/05/18)
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- Superbase-Mediated Indirect Friedl?nder Reaction: A Transition Metal-Free Oxidative Annulation toward Functionalized Quinolines
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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.
- Rahul,Nitha,Omanakuttan, Vishnu K.,Babu, Sheba Ann,Sasikumar,Praveen, Vakayil K.,Hopf, Henning,John, Jubi
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p. 3081 - 3089
(2020/05/08)
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- Pd-Catalyzed Tandem Reaction of 2-Aminostyryl Nitriles with Arylboronic Acids: Synthesis of 2-Arylquinolines
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A novel palladium-catalyzed protocol for the synthesis of 2-arylquinolines via tandem reaction of 2-aminostyryl nitriles with arylboronic acids has been developed with good functional group tolerance. The presented approach offers a new synthetic pathway toward the core structures of 2-arylquinolines compared to classical condensation reaction of (E)-2-aminostyryl aryl ketones. Moreover, the present synthetic route could be readily scaled up to gram quantity without difficulty. Preliminary mechanistic experiments showed that this transformation involves a nucleophilic addition of aryl palladium species to the nitrile to generate an aryl ketone intermediate followed by an intramolecular cyclization and dehydration to quinoline ring.
- Xu, Tong,Shao, Yinlin,Dai, Ling,Yu, Shulin,Cheng, Tianxing,Chen, Jiuxi
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p. 13604 - 13614
(2019/10/16)
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- Metal-Ligand Cooperative Approach to Achieve Dehydrogenative Functionalization of Alcohols to Quinolines and Quinazolin-4(3 H)-ones under Mild Aerobic Conditions
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A simple metal-ligand cooperative approach for the dehydrogenative functionalization of alcohols to various substituted quinolines and quinazolin-4(3H)-ones under relatively mild reaction conditions (≤90 °C) is reported. Simple and easy-to-prepare air-stable Cu(II) complexes featuring redox-active azo-aromatic scaffolds, 2-arylazo-(1,10-phenanthroline) (L1,2), are used as catalyst. A wide variety of substituted quinolines and quinazolin-4(3H)-ones were synthesized in moderate to good isolated yields via dehydrogenative coupling reactions of various inexpensive and easily available starting materials under aerobic conditions. A few control experiments and deuterium labeling studies were carried out to understand the mechanism of the dehydrogenative coupling reactions, which indicate that both copper and the coordinated azo-aromatic ligand participate in a cooperative manner during the catalytic cycle.
- Das, Siuli,Sinha, Suman,Samanta, Deepannita,Mondal, Rakesh,Chakraborty, Gargi,Branda?, Paula,Paul, Nanda D.
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p. 10160 - 10171
(2019/08/20)
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- Dehydrogenative Synthesis of Quinolines, 2-Aminoquinolines, and Quinazolines Using Singlet Diradical Ni(II)-Catalysts
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Simple, straightforward, and atom economic methods for the synthesis of quinolines, 2-aminoquinolines, and quinazolines via biomimetic dehydrogenative condensation/coupling reactions, catalyzed by well-defined inexpensive and easy to prepare singlet diradical Ni(II)-catalysts featuring two antiferromagnetically coupled singlet diradical diamine type ligands are described. Various polysubstituted quinolines, 2-aminoquinolines, and quinazolines were synthesized in moderate to good yields from different low-cost and readily accessible starting materials. Several control experiments were carried out to get insight into the reaction mechanism which shows that the nickel and the coordinated diamine ligands participate in a synergistic way during the dehydrogenation of alcohols.
- Chakraborty, Gargi,Sikari, Rina,Das, Siuli,Mondal, Rakesh,Sinha, Suman,Banerjee, Seemika,Paul, Nanda D.
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p. 2626 - 2641
(2019/02/26)
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- DIARYLUREAS AS CB1 ALLOSTERIC MODULATORS
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The present invention provides novel diarylurea derivatives (compounds of formula (I)) and their uses. The compounds of the present invention are demonstrated to be allosteric modulators of the CB1 receptor, and therefore useful for the treatment of diseases and conditions mediated by CB1.
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Paragraph 69; 72; 95
(2018/12/02)
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- Novel Diarylurea Based Allosteric Modulators of the Cannabinoid CB1 Receptor: Evaluation of Importance of 6-Pyrrolidinylpyridinyl Substitution
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Allosteric modulators of the cannabinoid CB1 receptor have recently been reported as an alternative approach to modulate the CB1 receptor for therapeutic benefits. In this study, we report the design and synthesis of a series of diarylureas derived from PSNCBAM-1 (2). Similar to 2, these diarylureas dose-dependently inhibited CP55,940-induced intracellular calcium mobilization and [35S]GTP-γ-S binding while enhancing [3H]CP55,940 binding to the CB1 receptor. Structure-activity relationship studies revealed that the pyridinyl ring of 2 could be replaced by other aromatic rings and the pyrrolidinyl ring is not required for CB1 allosteric modulation. 34 (RTICBM-74) had similar potencies as 2 in all in vitro assays but showed significantly improved metabolic stability to rat liver microsomes. More importantly, 34 was more effective than 2 in attenuating the reinstatement of extinguished cocaine-seeking behavior in rats, demonstrating the potential of this diarylurea series as promising candidates for the development of relapse treatment of cocaine addiction.
- Nguyen, Thuy,German, Nadezhda,Decker, Ann M.,Langston, Tiffany L.,Gamage, Thomas F.,Farquhar, Charlotte E.,Li, Jun-Xu,Wiley, Jenny L.,Thomas, Brian F.,Zhang, Yanan
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p. 7410 - 7424
(2017/09/22)
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- Quinoline derivatives and their use
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The invention discloses a quinoline derivative and a usage thereof, a compound with a structure as shown in a formula (I) and or a pharmaceutically acceptable salt of the compound. The compound or the pharmaceutically acceptable salt thereof disclosed by the invention can be applied to the field of preparation of drugs for preventing or treating tumors.
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Paragraph 0099-0101; 0189; 0190; 0204; 0205
(2017/03/14)
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- Meta-Selective CAr-H Nitration of Arenes through a Ru3(CO)12-Catalyzed Ortho-Metalation Strategy
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The first example of transition metal-catalyzed meta-selective CAr-H nitration of arenes is described. With the use of Ru3(CO)12 as the catalyst and Cu(NO3)2·3H2O as the nitro source, a wide spectrum of arenes bearing diversified N-heterocycles or oximido as the directing groups were nitrated with meta-selectivity exclusively. Mechanism studies have demonstrated the formation of a new 18e-octahedral ruthenium species as a key ortho-CAr-H metalated intermediate, which may be responsible for the subsequent meta-selective electrophilic aromatic substitution (SEAr). Moreover, this approach provides a fast-track strategy for atom/step economical synthesis of many useful pharmaceutical molecules.
- Fan, Zhoulong,Ni, Jiabin,Zhang, Ao
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supporting information
p. 8470 - 8475
(2016/07/26)
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- Efficient Synthesis of Quinolines via a Knoevenagel/Staudinger/aza-Wittig Sequence
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A simple and efficient method for the construction of quinoline derivatives from 2-azidobenzaldehyde and various carbonyl compounds was developed. The process involves a Knoevenagel condensation of 2-azidobenzaldehyde with carbonyl compound and subsequently an intramolecular normal Staudinger/aza-Wittig reaction to form the quinolone ring in satisfactory yields.
- Qu, Feng,He, Ping,Hu, Ruo-Fei,Cheng, Xiao-Hong,Wang, Song,Wu, Jing
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p. 2802 - 2809
(2015/12/23)
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- Synthesis of 2-substituted quinolines from alcohols
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A facile and economic method for the construction of 2-substituted quinolines by AgOTf-catalyzed 2-aminobenzyl alcohol and alkyne/ketone or 2-aminophenethyl alcohol and aldehyde has been developed. The electronic properties of the substituents on the alkyne, ketone, and aldehyde were investigated. It was found that molecules with both electron-donating and -withdrawing substituents were perfectly suitable substrates for this transformation, and the expected products were obtained in moderate to excellent yields. Moreover, the use of inexpensive starting materials and environmentally benign oxidants makes this atom efficient method particularly attractive.
- Xu, Xuefeng,Zhang, Xu,Liu, Wenming,Zhao, Qiang,Wang, Zhiqiang,Yu, Lintao,Shi, Fu
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supporting information
p. 3790 - 3792
(2015/06/08)
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- Unexpected and divergent reactions of N -formyl-1,2-dihydroquinolines with sodium azide: Highly chemoselective formation of 2-substituted quinolines and isoxazolo[4,3- c ]quinolines
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Efficient and divergent synthesis of 2-substituted quinolines and isoxazolo[4,3-c]quinolines was achieved from N-formyl-1,2-dihydroquinolines with the aid of sodium azide. The synthesis is substituent-dependent. Thus N-formyl-1,2-dihydroquinolines with a hydrogen atom at the 3-position afforded 2-substituted quinolines in good to excellent yields, while with a 3-formyl group, N-formyl-1,2-dihydroquinolines unexpectedly gave isoxazolo[4,3-c] quinolines in high yields. Georg Thieme Verlag Stuttgart.
- Su, Weike,Yu, Jingbo,Li, Zhenhua,Zheng, Bei
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supporting information; experimental part
p. 1281 - 1284
(2010/07/03)
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