Rajkumar Joshi

Synthesis and in vitro antibacterial activity of new steroidal thiosemicarbazone derivatives

We investigated the antibacterial activity of some new steroidal thiosemicarbazone derivatives, prepared from the reaction of cholest-5-en-7-one with thiosemicarbazides, in ethanol in the presence of a few drops of HCl at 80 degrees C in high yield. All the compounds have been characterized by means of elemental analyses, IR, 1H NMR and mass spectroscopic data, to find an effective antibacterial agent. The antibacterial activity was first tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) of compounds was determined. The results showed that the steroidal thiosemicarbazones derivatives inhibit growth of both types of the bacteria (Gram-positive and Gram-negative). The acetoxy and chloro derivatives of cyclopentyl and cyclohexyl amine thiosemicarbazones were found to have more antibacterial activity than the other derivatives.

Status and challenges of municipal solid waste management in India: A review

Abstract The abysmal state of and challenges in municipal solid waste management (MSWM) in urban India is the motivation of the present study. Urbanization contributes enhanced municipal solid waste (MSW) generation and unscientific handling of MSW degrades the urban environment and causes health hazards. In this paper, an attempt is made to evaluate the major parameters of MSWM, in addition to a comprehensive review of MSW generation, its characterization, collection, and treatment options as practiced in India. The current status of MSWM in Indian states and important cities of India is also reported. The essential conditions for harnessing optimal benefits from the possibilities for public private partnership and challenges thereof and unnoticeable role of rag-pickers are also discussed. The study concludes that installation of decentralized solid waste processing units in metropolitan cities/towns and development of formal recycling industry sector is the need of the hour in developing countries like India.

Organotin(IV) oxo -homoscorpionate: preparation, spectroscopic characterization and antimicrobial properties

An oxo-homoscorpionate ligand [potassium bis(phthalato)borate] (KL) was prepared by solid state reaction of potassium borohydride and phthalic acid (1 : 3 molar ratio). The ligand is uninegative and can be a bi, tri and tetra-dentate chelating agent. The di- and tri-organotin(IV) complexes of this ligand are formed by replacement of chloride in R2SnCl2 and (R = methyl, butyl and R′ = phenyl and butyl). The ligand and all its complexes were characterized by elemental analyses and spectral studies (IR, 1H, 13C, 119Sn NMR and ESI mass spectra). Spectroscopic data reveal that all the complexes are hexacoordinate; the diorganotin complexes have trans octahedral geometry while the triorganotin complexes are distorted octahedral geometry. The toxicity of these organotin(IV) derivatives on selected microbes was considered. The compounds exhibit antibacterial (Bacillus anthracius and Escherichia coli) and antifungal (Candida albicans and Penicillium italicum) activities in vitro. The ligand shows less toxicity towards the microorganisms and its toxicity significantly increased after complexation with organotin(IV). Triorganotin derivatives (R3SnL) of the ligand are more effective compared to diorganotin derivatives (R2SnL2).

Antimicrobial studies of newly synthesized organotin(IV) complexes of dihydrobis(2-mercaptothiazolinyl)borate

Four organotin(IV) complexes of dihydrobis(2-mercaptothiazolinyl)borate were synthesized and characterized by elemental analysis and spectroscopic techniques (IR, 1H-NMR, 13C-NMR, 11B-NMR, and 119Sn-NMR). All the compounds were screened against bacterial, fungal, and cyanobacterial strains. Among the complexes, triorganotin(IV) complexes show better inhibition growth as compared to diorganotin(IV) complexes.

Structural and antimicrobial studies of potassium hydrotris(2-mercaptobenzathiazolyl)borate and its organotin(IV) derivatives

Potassium hydrotris(2-mercaptobenzathiazolyl)borate (KL) was formed by the solid state reaction of potassium borohydride and 2-mercaptobenzathiazoline. This ligand was reacted with R n SnCl4−n (R  = methyl, butyl and phenyl, n  = 2 and 3) in dichloromethane and four different neutral organotin(IV) complexes were obtained. All compounds were characterized by elemental analyses, FT-IR and multinuclear NMR (1H, 13C, 11 B and 119Sn) spectroscopy. Spectroscopic data indicate the six-coordinated nature of tin in its di and triorganotin(IV) complexes. To check the toxic potential of the ligand and its organotin(IV) complexes, selected bacterial (E. coli, S. epidemidis and S. dysenteriae) and fungal (A. niger, C. albicanes and A. flaves) species were screened. The results were compared with standard drugs kinamycine and miconazole for bacterial and fungal activity, respectively. The toxicity of the organotin(IV) complexes depends on the number and nature of organic groups attached to the tin atom; triorganotin(IV) complexes exhibit better inhibition than diorganotin(IV) complexes. All compounds were also screened on the cyanobacterial strains (Aulosira fertillissma, Anabaena variabilis, Anabaena species and Nostoc muscorum). Results show that the compounds inhibit the growth of organisms at very low concentration.

Municipal solid waste as a source of energy

Air, water and soil contamination is the major source generated from municipal solid wastes. In current scenario air, water, and soil are polluted because of the uninhibited decomposition of solid wastes. The systematic treatment of municipal solid wastes leads to the economical source of energy. Appropriate municipal waste management (MSW) strategy be implemented to minimize environmental impact and subsequent energy recovery. In this mini review report we have discussed about the technological aspects of energy production from MSW. Overall energy potential and future prediction has also been reported.