- Microwave-assisted synthesis of bis(N-substituted thiazol-2-amine) derivatives and their biological activities
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New 4,4′-(4,6-dimethoxy-1,3-phenylene)-bis(N-substituted thiazol-2-amine) derivatives 5a-j were synthesized from 1,1′-(4,6-dimethoxy-1,3-phenylene)-bis(2-bromoethanone) 3 and substituted thioureas 4a-j under conventional and microwave irradiation conditio
- Baba, N.H. Kumar,Ashok,Rao, Boddu Ananda,Sarasija, Madderla,Murthy,Srinivasarao, Vankadari,Parthasarathy, Tigulla
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- Microwave Assisted Synthesis and Biological Activity of Novel Bis{2-[2-(substituted benzylidene)hydrazinyl]thiazole} Derivatives
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Abstract—New 4,4'-(4,6-dimethoxy-1,3-phenylene)bis{2-[2-(substituted benzylidene)hydrazinyl]thiazole} derivatives (5a–5j) have been synthesized from the corresponding 1,1'-(4,6-dimethoxy-1,3-phenylene)bis(2,2- dibromoethanone) and substituted thiosemicarbazones by the conventional method and under microwave irradiation. Structures of the synthesized compounds were characterized by FT-IR, 1H, and 13C NMR and Mass spectra. The products were evaluated for their in vitro antibacterial activity against Gram-positive and Gramnegative stains. Some of the compounds 5b, 5f, 5h demonstrated high activity against B. subtilis (+ve), compound 5c exhibited high activity against E. coli (–ve) and P. aeruginosa (–ve) stains. Among the titled compounds also evaluated for their in vitro antimycobacterial activity, the product 5b demonstrated pronounced antimycobacterial activity against M. bovis stain.
- Kumar Baba,Ashok,Rao, Boddu Ananda,Sarasija, Madderla,Murthy
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p. 580 - 586
(2018/04/24)
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- Microwave assisted synthesis of some novel bis-(2-substituted imidazole[2,1-b] [1,3,4] thiadiazole) derivatives and their biological activities
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A new series of 6,6'-(4,6-dimethoxy-1,3-phenylene)bis (2- substituted imidazo[2,1-b] [1,3,4]thiadiazole) derivatives (5a-5h) were synthesized from corresponding 1,1'-(4,6-dimethoxy-1,3-phenylene)bis(2-bromoethanone) and substituted 1,3,4-thiadiazol-2-amine under conventional and microwave irradiation conditions. The structures of all the synthesized compounds were characterized by Fourier transform infrared,1H nuclear magnetic resonance (NMR),13C NMR, mass, and elemental analysis. All products were subjected to in vitro antibacterial and antimycobacterial evaluation. Some of the compounds exhibit good activities against Staphylococcus aureus (+ve), Bacillus subtilis (+ve) strains, and Mycobacterium bovis strain.
- Kumar Baba,Ashok,Rao, Boddu Ananda,Sarasija, Madderla,Murthy
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p. 163 - 168
(2018/09/14)
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- Synthesis and antimicrobial activity of bischalcone derivatives
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Several bischalcones (2a-h and 5a-e) and flavones (3a-f) were synthesized and evaluated for their antimicrobial actions. Bischalcones were prepared by condensing 1,1′-(4,6-dimethyl-1,3-phenylene)diethanone (1) or 1-(5-acetyl-2,4-dimethoxyphenyl)-1-ethanone (4) with arylaldehydes. Bischalcones were cyclized in presence of iodine to give corresponding flavones (3a-f). An alternative route to synthesize the flavones consisted in preparing the diester derivatives (6a-f) of (1) with different aromatic acids, which could be converted to β-diketones followed by cyclization to give the corresponding flavones. However, all the attempts in this direction were unsuccessful and it could not be possible to proceed beyond diester stage; six diester derivatives (6a-f) were synthesized. The structures of the synthesized compounds were assigned on the basis of 1H NMR, mass spectral data and microanalyses results. The antimicrobial screening was performed at a concentration of 100 μg/mL by cup plate method; the compounds inhibiting growth of one or more of the microorganisms were further tested for their minimum inhibitory concentration (MIC) by turbidity method. Preliminary antimicrobial results revealed that the compounds 2a-h and 3a-f were significant in their antibacterial and antifungal activities. MICs results showed that the compound 2f exhibited very good activity against E. coli, P. aeruginosa, and C. albicans with MIC-12.5 μg/mL. Similar type of activity was shown the compound 3a against S. aureus and C. albicans with MIC-12.5 μg/mL. Another compound, 3f, was active against P. aeruginosa and C. albicans with MIC-12.5 μg/mL. Methylation of the two chelated hydroxyls (5a-e) significantly reduced the activity. However, oxidative cyclization of bischalcones resulted in compounds (3a-f) which were found to be considerably active. Diesters (6a-f) were insignificant in their antimicrobial activities.
- Husain, Asif,Ahmad, Aftab,Mkhalid, Ibraheem Ahmed I.,Mishra, Ravinesh,Rashid, Mohd
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p. 1578 - 1586
(2013/07/26)
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- Leukotriene B4 Receptor Antagonists: The LY255283 Series of Hydroxyacetophenones
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A series of hydroxyacetophenones was prepared for evaluation as leukotriene B4 (LTB4) receptor antagonists, culminating in 1-oxy>phenyl>ethanone (compound 35, LY255283).Using an assay for inhibition of specific LTB4 binding to human PMN, we found that substitution of a nonpolar substituent in the 5-position was required for activity.Best activity was realized with hydrogen in the 3-position, hydroxyl in the 2-position, short chain alkyl ketone in the 1-position, and a six- or eight-carbon chain linking the oxygen in the 4-position with an unsaturated terminal function.Compound 35, having an IC50 of 87 nM in the binding assay, was chosen for further preclinical evaluation.
- Herron, David K.,Goodson, Theodore,Bollinger, Nancy G.,Swanson-Bean, Dorothy,Wright, Ian G.,et al.
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p. 1818 - 1828
(2007/10/02)
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