Browsing by Author "Achur, R."

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Synthesis and biological evaluation of new imidazo[2,1-b][1,3,4]thiadiazole-benzimidazole derivatives
(2015) Ramprasad, J.; Nayak, N.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.; Peethambar, S.K.; Achur, R.; Kumar, H.S.S.
In this report, we describe the synthesis and biological evaluation of a new series of 2-(imidazo[2,1-b][1,3,4]thiadiazol-5-yl)-1H-benzimidazole derivatives (5a-ac). The molecules were analyzed by 1H NMR, 13C NMR, mass spectral and elemental data. The structure of one of the pre-final compounds, 6-(4-methoxyphenyl)-2-(4-methylphenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (4d) and that of a target compound, 2-[2-methyl-6-(4-methyl phenyl) imidazo[2,1-b][1,3,4]thiadiazol-5-yl]-1H-benzimidazole (5aa) were confirmed by single crystal XRD studies. All the target compounds were screened for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Seven (5c, 5d, 5l, 5p, 5r, 5z and 5aa) out of twenty nine compounds showed potent anti-tubercular activity with a MIC of 3.125 ?g/mL. A p-substituted phenyl group (p-tolyl or p-chlorophenyl) in the imidazo[2,1-b][1,3,4]thiadiazole ring and/or a chloro group in the benzimidazole ring enhance anti-tuberculosis activity whereas a nitro group in the benzimidazole ring reduces the activity. In the antibacterial screening, compounds 5i, 5w and 5ac showed promising activity against the tested bacterial strains. Further, antifungal and antioxidant activities of these molecules were also investigated. In the cytotoxicity study, the active antitubercular compounds exhibited very low toxicity against a normal cell line. 2015 Elsevier Masson SAS.
Synthesis and biological evaluation of new imidazo[2,1-b][1,3,4]thiadiazole-benzimidazole derivatives
(Elsevier Masson SAS infos@masson.fr 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2015) Ramprasad, J.; Nayak, N.; Udayakumar, U.; Yogeeswari, P.; Sriram, D.; Peethambar, S.K.; Achur, R.; Santosh Kumar, H.S.S.
In this report, we describe the synthesis and biological evaluation of a new series of 2-(imidazo[2,1-b][1,3,4]thiadiazol-5-yl)-1H-benzimidazole derivatives (5a-ac). The molecules were analyzed by 1H NMR, 13C NMR, mass spectral and elemental data. The structure of one of the pre-final compounds, 6-(4-methoxyphenyl)-2-(4-methylphenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (4d) and that of a target compound, 2-[2-methyl-6-(4-methyl phenyl) imidazo[2,1-b][1,3,4]thiadiazol-5-yl]-1H-benzimidazole (5aa) were confirmed by single crystal XRD studies. All the target compounds were screened for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Seven (5c, 5d, 5l, 5p, 5r, 5z and 5aa) out of twenty nine compounds showed potent anti-tubercular activity with a MIC of 3.125 ?g/mL. A p-substituted phenyl group (p-tolyl or p-chlorophenyl) in the imidazo[2,1-b][1,3,4]thiadiazole ring and/or a chloro group in the benzimidazole ring enhance anti-tuberculosis activity whereas a nitro group in the benzimidazole ring reduces the activity. In the antibacterial screening, compounds 5i, 5w and 5ac showed promising activity against the tested bacterial strains. Further, antifungal and antioxidant activities of these molecules were also investigated. In the cytotoxicity study, the active antitubercular compounds exhibited very low toxicity against a normal cell line. © 2015 Elsevier Masson SAS.
Synthesis of new pyrazole-triazole hybrids by click reaction using a green solvent and evaluation of their antitubercular and antibacterial activity
(2016) Nayak, N.; Ramprasad, J.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.; Kumar, H.S.S.; Peethambar, S.K.; Achur, R.
A new series of pyrazole-based 1,2,3-triazole derivatives (6a-x) were synthesized by employing click reaction using a 2:1 mixture of PEG-400 and water as green solvent. The synthesized intermediate and final compounds were characterized by 1H NMR, 13C NMR, and mass spectra and elemental analysis techniques. The structure of one of the final compounds, 6a was evidenced by single crystal X-ray diffraction study. Among the twenty-four compounds, five compounds (6a, 6b, 6d, 6f, and 6g) showed significant antitubercular activity against Mycobacterium tuberculosis H37Rv with a minimum inhibitory concentration (MIC) ? 6.25 ?g/mL. The 4-(((5-(4-Chlorophenyl)-1-phenyl-1H-pyrazol-3-yl)methoxy)methyl)-1-cyclohexyl-1H-1,2,3-triazole (6g) was the most potent compound of the series, which showed a MIC of 3.13 ?g/mL. The cytotoxicity study of active anti-TB compounds on normal Vero cells revealed that the compounds are non-toxic with a high selectivity index (>37). Most of the pyrazole-1,2,3-triazole derivatives with a 4-chlorophenyl substitution at position-5 of the pyrazole ring showed a better anti-TB activity than the corresponding 4-bromophenyl or 4-methoxyphenyl substituted derivatives. The target compounds were also evaluated for their in vitro antibacterial activity and six compounds (6a, 6c, 6d, 6e, 6l, and 6w) showed promising inhibition activity against four tested strains. Springer Science+Business Media Dordrecht 2015.
Synthesis of new pyrazole-triazole hybrids by click reaction using a green solvent and evaluation of their antitubercular and antibacterial activity
(Springer Netherlands, 2016) Nayak, N.; Ramprasad, J.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.; Santosh Kumar, H.S.S.; Peethambar, S.K.; Achur, R.
A new series of pyrazole-based 1,2,3-triazole derivatives (6a-x) were synthesized by employing click reaction using a 2:1 mixture of PEG-400 and water as green solvent. The synthesized intermediate and final compounds were characterized by 1H NMR, 13C NMR, and mass spectra and elemental analysis techniques. The structure of one of the final compounds, 6a was evidenced by single crystal X-ray diffraction study. Among the twenty-four compounds, five compounds (6a, 6b, 6d, 6f, and 6g) showed significant antitubercular activity against Mycobacterium tuberculosis H37Rv with a minimum inhibitory concentration (MIC) ? 6.25 ?g/mL. The 4-(((5-(4-Chlorophenyl)-1-phenyl-1H-pyrazol-3-yl)methoxy)methyl)-1-cyclohexyl-1H-1,2,3-triazole (6g) was the most potent compound of the series, which showed a MIC of 3.13 ?g/mL. The cytotoxicity study of active anti-TB compounds on normal Vero cells revealed that the compounds are non-toxic with a high selectivity index (>37). Most of the pyrazole-1,2,3-triazole derivatives with a 4-chlorophenyl substitution at position-5 of the pyrazole ring showed a better anti-TB activity than the corresponding 4-bromophenyl or 4-methoxyphenyl substituted derivatives. The target compounds were also evaluated for their in vitro antibacterial activity and six compounds (6a, 6c, 6d, 6e, 6l, and 6w) showed promising inhibition activity against four tested strains. © Springer Science+Business Media Dordrecht 2015.