- Ru-NHC-Catalyzed Asymmetric Hydrogenation of 2-Quinolones to Chiral 3,4-Dihydro-2-Quinolones
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Direct enantioselective hydrogenation of unsaturated compounds to generate chiral three-dimensional motifs is one of the most straightforward and important approaches in synthetic chemistry. We realized the Ru(II)-NHC-catalyzed asymmetric hydrogenation of 2-quinolones under mild reaction conditions. Alkyl-, aryl- and halogen-substituted optically active dihydro-2-quinolones were obtained in high yields with moderate to excellent enantioselectivities. The reaction provides an efficient and atom-economic pathway to construct simple chiral 3,4-dihydro-2-quinolones. The desired products could be further reduced to tetrahydroquinolines and octahydroquinolones.
- Daniliuc, Constantin,Glorius, Frank,Hu, Tianjiao,Lückemeier, Lukas
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supporting information
p. 23193 - 23196
(2021/09/25)
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- Phenothiazine and amide-ornamented novel nitrogen heterocyclic hybrids: synthesis, biological and molecular docking studies
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The synthesis of novel hybrids, namely, phenothiazine and amide-ornamented nitrogen heterocycles (25-34) has been accomplished utilizing a multi-step synthetic protocol and the structures have been established based on physical and spectral techniques. Of these, the hybrids possessing meta-nitro (26), para-fluoro (28), meta- and para-methyl (31), ortho-bromo (33) and ortho- and para-dimethyl (34) phenyl carboxamide scaffolds exhibited superior anti-inflammatory profiles over the standard diclofenac sodium. A hybrid integrated with a para-fluorophenyl carboxamide moiety (28) showed the highest DPPH radical scavenging activity among the chemical entities synthesized. Furthermore, the results of anticancer evaluations implied that the hybrid tethered with a phenyl carboxamide structural unit (29) exerted superior activity when compared with other hybrids against the pancreatic cancer cells SW1990 and AsPC1. Molecular docking between the hybrid 29 and B-cell lymphoma 2 reflects its appreciable binding affinity (-8.84 kcal mol-1). The results revealed that these chemical entities can serve as potent biological agents and/or efficient intermediates for the construction of potent biological agents.
- Iniyaval, Shunmugam,Karuppasamy, Ayyanar,Lim, Wei-Meng,Mai, Chun-Wai,Padmavathy, Krishnaraj,Ramalingan, Chennan,Sivaramakarthikeyan, Ramar
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p. 4049 - 4060
(2020/03/19)
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- Phenothiazine and amide-ornamented dihydropyridines: Via a molecular hybridization approach: Design, synthesis, biological evaluation and molecular docking studies
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A series of novel phenothiazinyldihydropyridine dicarboxamides 7a-7j was synthesized by adopting a multi-step synthetic strategy and characterized through physical and spectral techniques. Among them, the chemical entities with para-fluoro (7d), ortho-bromo and-fluoro (7f and 7i), ortho- A nd para-methyl (7e) and meta- A nd para-methoxy (7h) substituents exhibited either similar or superior anti-inflammatory activities with respect to the standard drug diclofenac sodium. Besides, the chemical entities with ortho-bromo and-fluoro substituents as well as meta-nitro substituents (7f, 7g and 7i) showed enhanced radical scavenging activities when compared to standard ascorbic acid. Furthermore, anticancer studies revealed that the meta- A nd para-chloro-substituted molecule 7a exerted the best activity against all the pancreatic cancer cells tested. Also, appreciable binding affinity (-8.10 kcal mol-1) was observed during molecular docking between B-cell lymphoma 2 and 7a. The structural diversifications of the potent chemical entities besides further exploration in connection with the biological profiles of the same are underway.
- Sivaramakarthikeyan, Ramar,Iniyaval, Shunmugam,Padmavathy, Krishnaraj,Liew, Hui-Shan,Looi, Chin-King,Mai, Chun-Wai,Ramalingan, Chennan
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p. 17046 - 17057
(2019/11/14)
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- Silver(I)-catalyzed tandem approach to β-oxo amides
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A facile and efficient AgI-catalytic approach is reported for the first time to synthesize β-oxo amides from β-oxo esters a with broad substrate scope in good to excellent yields. Crossover and in situ NMR studies confirmed that the reaction occurred through a new pathway and not by the traditional condensation reaction. The key advantages of this method are the readily available starting materials, the air-stable reaction, the simple protocol, and the environmental friendliness. A new, catalytic approach to the synthesis of β-oxo amides from β-oxo esters with a broad substrate scope in good to excellent yields was developed. In situ NMR spectroscopy and crossover experiments confirmed the reaction mechanism.
- Vandavasi, Jaya Kishore,Hsiao, Cheng-Tien,Hu, Wan-Ping,Boominathan, Siva Senthil Kumar,Wang, Jeh-Jeng
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supporting information
p. 3171 - 3177
(2015/05/13)
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- Synthesis, screening for antitubercular activity and 3D-QSAR studies of substituted N-phenyl-6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydro-pyrimidine-5-carboxamides
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Multi-drug resistance to commonly used antitubercular drugs has propelled the development of new structural classes of antitubercular agents. This paper reports the synthesis, evaluation and 3D-QSAR analysis of a set of substituted N-phenyl-6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxamides as antitubercular agents. Substituted acetoacetanilides were reacted with various aromatic aldehydes and urea which yielded the tetrahydropyrimidine derivatives with a phenyl carbamoyl group at C5 position, and with various substitutions on the 4-phenyl and the N-phenyl aromatic rings. All compounds were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv strain. The QSAR models were generated on a training set of 23 molecules. The molecules were aligned using the atom-fit and field-fit techniques. The CoMFA and CoMSIA models generated on the molecules aligned by the atom-fit method show a correlation coefficient (r2) of 0.98 and 0.95 with cross-validated r2(q2) of 0.68 and 0.58, respectively. The 3D-QSAR models were externally validated against a test set of 7 molecules for which the predictive r2 (rpred2) is recorded as 0.41 and 0.32 for the CoMFA and CoMSIA models, respectively. The CoMFA and CoMSIA contours helped to design some new molecules with improved activity.
- Virsodia, Vijay,Pissurlenkar, Raghuvir R.S.,Manvar, Dinesh,Dholakia, Chintan,Adlakha, Priti,Shah, Anamik,Coutinho, Evans C.
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p. 2103 - 2115
(2008/12/23)
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- Method for preparing 4-hydroxycinnolines in a pH controlled system
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In the preparation of a 4-hydroxycinnoline wherein the diazonium salt of a 2-aminoacetophenone in aqueous solution is allowed to undergo cyclocondensation, the improvement that comprises maintaining the pH of the solution between about 4.0 and 8.5 during the cyclocondensation.
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