S. L. Belagali

A method for the chromatographic resolution of tetrahydropyran-2-ones

Abstract The spirocyclic ortholactones prepared from certain tetrahydropyran-2-ones (valerolactones) and (1R)-1-phenylpropan-1,3-diol are readily separable by flash chromatography on silica gel. Hydrolysis of the resolved ortholactones then provides the pure homochiral lactones.

Synthetic and antibacterial studies on some new furanopeptides.

A series of new furanopeptides (3) are prepared by the coupling of arylsubstituted furoic acids (1) with amino acid methyl esters, di and tetra-peptide methyl esters using dicyclohexyl carbodiimide (DCC) as coupling agent. Some of the newly synthesized compounds are characterized on the basis of IR, 1H NMR, mass spectral data and elemental analysis. Some of the selected compounds are also tested for their antibacterial properties.

Guanidinyl benzothiazole derivatives: Synthesis and structure activity relationship studies of a novel series of potential antimicrobial and antioxidants

A series of N-phenyl-substituted and disubstituted guanidinyl benzothiazole derivatives 4a–4m were synthesized and characterized as novel antimicrobial and antioxidant agents. The in-vitro antioxidant activities of these compounds were evaluated and compared with commercial antioxidants, using ascorbic acid (AA) and employing 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid (ABTS) assay. The results showed that IC50 values of compounds 4a and 4m were similar to the IC50 values of the standard. This assay indicates the good activities of these compounds. In addition, the in-vitro antimicrobial activities of these compounds were evaluated and the results demonstrated that the compounds 4i and 4l exhibited excellent antimicrobial activities. Compounds 4c and 4i having electron withdrawing groups at p-position and compound 4l and 4m having electron donating groups at o-position showed better antimicrobial activities compared to the standard.Graphical Abstract

Synthesis and biological evaluation of Pseudostellarin D

Abstract Pseudostellarin D, a natural cyclic heptapeptide, was successfully synthesized and characterized by IR, 1 H NMR, 13 C NMR, FABMS and elemental analysis. The synthesized compound was evaluated for antibacterial, antifungal, anti-inflammatory and anthelmintic activities.

Characterization of Polyaniline for Optical and Electrical Properties

Semiconductors have the conducting properties in between conductors and insulators. They have wide range of applications in the field of electronics and communications. Silicon compounds are mainly used as semiconducting materials, but the method of production is costly. Hence, the organic semiconductors can be considered, because of cheap raw materials for synthesis and their mode of construction or design. The organic semiconductors like polyaniline (Pani) can be considered because of its aromatic ring and lone pair of electrons on nitrogen for conducting electricity. It is a cheap, easily synthesizable and environmentally stable compound, with exciting electrochemical, optical and electrical properties. The synthesis was done by oxidation of aniline using hydrochloric acid and ammonium persulphate (APS), which forms an emeraldine salt. It was characterized by FT-IR, XRD, SEM NIR and UV-Vis Spectrophotometer.

Synthesis and biological evaluation of pseudostellarin B.

A new potent bioactive cyclic peptide pseudostellarin B has been synthesised. The structure was elucidated by elemental analyses, IR, 1H NMR, 13C NMR and FAB mass spectral data. The synthesised compound was also screened for its antibacterial, antifungal, antiinflammatory and anthelmintic activities.

Synthesis, characterization, and biological study of phenylalanine amide derivatives

In the present study, a series of amide derivatives of 4-nitro-l-phenylalanine were synthesized with good yield from 4-nitro-l-phenylalanine and substituted anilines using propylphosphonic anhydride (T3P®) as coupling reagent and were characterized through the IR, LC–MS, 1H and 13C NMR spectral studies. The isolated products were screened for antimicrobial and antioxidant activities. Some of the compounds showed Microsporum gypsuem activity or were active against Candida albicans, also a few of compounds showed antibacterial activities. The resultant compounds screened for anti-oxidant activity, which showed good activity for DPPH scavenging and ABTS assay methods and others had moderately activity. Some amide compounds act as metal chelating ligands with Fe2+ ions.Graphical abstract

Synthesis of a new cyclic peptide, Pseudostellarin G

A new biologically active cyclic peptide, Pseudostellarin G was synthesized and the structure was established on the basis of analytical, IR, NMR and mass spectral data. The newly synthesized compound was screened for its antimicrobial and pharmacological activities.

Synthesis of Benzothiazolyl Guanidinyl Derivatives and their In-Vitro Antimicrobial and Antioxidant Activity

Background: Compounds containing CN3 groups are named as guanidine derivatives, which have a rich history in biological and bio-inspired activity. Many guanidine moieties are reported for the antimicrobial activity. Present study aims to the enhancement of bio-activity of the guanidine subunits by conjugating with benzothiazole. Methods: A new series of benzothiazole guanidines have been synthesized from the reaction of thiourea derivatives of 6-substituted benzothiazoles with different substituted anilines in presence of HgCl2. The synthesized compounds were characterized through FT-IR, mass and 1H NMR spectral techniques. The synthesized compounds were screened for the Antimicrobial activity by disc diffusion method and antioxidant activity was assigned by DPPH and ABTS assay. Results: The products were screened for antimicrobial activity. They were found to exhibit moderate to potent activity against the tested microorganisms and have shown minimum inhibition concentration of 1.56 µg/mL for Candida albicans, 0.78 µg/mL for Aspergillus niger, 25 µg/mL for S. aureus and 12.5 µg/mL for E. coli. The derivatives were also tested for antioxidant DPPH and ABTS assays and they were found to have significant activities compared to the standards. Conclusion: In the present work, a new series of benzothiazole guanidinyl derivatives were synthesized in good yields by employing HgCl2 reagent. Synthesized compounds were screened for antimicrobial and antioxidant activities and compounds containing p-methoxy, o-hydroxy showed better antioxidant activities and antimicrobial activities.

Study of Adsorption Phenomena by Using Almond Husk for Removal of Aqueous Dyes

Among air and soil, water pollution is considered as an important one. Deterioration of water resources by the addition of various pollutants leads to the major threat to water quality and use of water for domestic purpose which leads to unaesthetic. For the plants, animals and human beings dyes are considered as most hazardous among various water pollutants. The present paper describes the adsorption behaviour of adsorbent almond husk with respect to dyes of Crystal violet, Bromocresol green, Pararosaniline and Victoria blue was investigated. The batch method was used and parameters like pH, adsorbent dosage, contact time and initial and final concentration of dyes were studied. Adsorbent used to be effective, with total removal of all dyes of 90, with higher percentage removal from bromocresol green 97.5, Crystal violet 96.9, Pararosaniline 95.6 and Victoria blue 95. Almond husk was an effective adsorbent with maximum percentage removal of 97.5 bromocresol green. Adsorbent was analysed by the instrument of scanning electron microscopy and Fourier infrared spectroscopy. In the present study almond husk almond husk was studied as a very good adsorbent for the removal of dyes from the aqueous media. Isotherm model of Langmuir, Freundlich and Dubinin-Radushkevich were considered to be favourable.