Synthesis and Antimicrobial Activity of 1,2-Benzothiazine Derivatives

© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).A number of 1,2-benzothiazines have been synthesized in a three-step process. Nine chalcones 1-9 bearing methyl, fluoro, chloro and bromo substituents were chlorosulfonated with chlorosulfonic acid to generate the chalcone sulfonyl chlorides 10-18. These were converted to the dibromo compounds 19-27 through reaction with bromine in glacial acetic acid. Compounds 19-27 were reacted with ammonia, methylamine, ethylamine, aniline and benzylamine to generate a library of forty-five 1,2-benzothiazines 28-72. Compounds 28-72 were evaluated for their antimicrobial activity using broth micro dilution techniques against two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), and two Gram-negative bacteria (Proteus vulgaris and Salmonella typhimurium). The results demonstrated that none of the compounds showed any activity against Gram-negative bacteria, P. vulgaris and S. typhimurium, however compounds 31, 33, 38, 43, 45, 50, 53, 55, 58, 60, 63 and 68 showed activity against Gram-positive bacteria, Bacillus subtilis and Staphylococcous aureus. The range of MIC and MBC was 25-600µg/ml; though some of the MIC and MBC concentrations were high indicating weak activity. Structure activity relationship studies revealed that the compounds with a hydrogen atom or an ethyl group on the nitrogen of the thiazine ring exerted antibacterial activity against Gram-positive bacteria. The results also showed that the compounds where the benzene ring of the benzoyl moiety contained a methyl group or chlorine or bromine atom in the para position showed higher antimicrobial activity. Similar influences were identified where either a bromine or chlorine atom was in the meta position.Peer reviewedFinal Published versio

The crystal structure, morphology and mechanical properties of diaquabis(omeprazolate)magnesium dihydrate

The crystal structure of diaqua¬bis(omeprazolate)magnesium dihydrate (DABOMD) in the solid state has been determined using single-crystal X-ray diffraction. Single crystals of DABOMD were obtained by slow crystallization in ethanol with water used as an antisolvent. The crystal structure shows a dihydrated salt comprising a magnesium cation coordinating two omeprazolate anions and two water molecules (W1) that are strongly bound to magnesium. In addition, two further water molecules (W2) are more weakly hydrogen-bonded to the pyridine nitro¬gen atom of each omeprazolate anion. The crystal structure was utilized to estimate key material properties for DABOMD, including crystal habit and mechanical properties, which are required for improved understanding and prediction of the behaviour of particles during pharmaceutical processing such as milling. The results from the material properties calculations indicate that DABOMD exhibits a hexagonal morphology and consists of a flat slip plane through the (100) face. It can be classed as a soft material based on elastic constant calculation and exhibits a two-dimensional hydrogen-bonding framework. Based on the crystal structure, habit and mechanical properties, it is anticipated that DABOMD will experience large disorder accompanied by plastic deformation during milling

A Fast, Stability-Indicating, and Validated Liquid Chromatography Method for the Purity Control of Lercanidipine Hydrochloride in Tablet Dosage Form

A robust, sensitive, and stability-indicating rapid resolution liquid chromato-graphy method for the simultaneous determination of process impurities and degradation products of lercanidipine hydrochloride in pharmaceutical dosage form was developed and validated. The chromatographic separation was performed on the Zorbax SB C18 [(50 × 4.6) mm] 1.8 μm column, using gradient elution of a potassium dihydrogen phosphate buffer (pH 3.5, 0.01 M) and acetonitrile. The flow rate was 1.0 ml/min and UV detection was performed at 220 nm. The method was further evaluated for its stability-indicating capability by hydrolytic, oxidative, thermal, thermal with moisture, and photolytic degradation studies. All acceptance criteria of the International Conference on Harmonization guidelines for validation were covered in the method validation. This method can be used for purity control during manufacture and real time stability studies. A shorter run time of 10 minutes and good solution stability for at least 48 hours allowed the quantification of more than 50 samples per day with comparatively lower costs than existing methods

Synthesis of heterocyclic and non-heterocyclic entities as antibacterial and anti-HIV agents

1871-18793,4-dimethoxy-1-[{(2-aryl/alkyl amino)-2-oxoethyl} amino]-ethylbenzene 4a-o and 2-[{2-(3,4-dimethoxy phenyl ethyl amino)-2-oxo ethyl}amino]-4,6-diaryl pyrimidines 5a-o have been synthesized and tested for their antibacterial and anti-HIV activities against different microorganisms. The structures of novel synthesized compounds have been established on the basis of elemental analyses, 1H NMR, IR and mass spectral data

Exploring antimicrobial and antimycobacterial potential of novel quinazoline based thiazolidin-4-ones

260-271To affiliate multiple bioactivities in a compact heteronuclei, two series of N-phenyl acetamides and thiazolidin-4-ones based quinazolines have been synthesized. The in vitro antimicrobial efficacy of the synthesized analogs has been assessed against two Gram-positive bacteria, six Gram-negative bacteria and four fungi. Furthermore, the final analogs have also been screened against Mycobacterium tuberculosis H37Rv in order to explore the antituberculosis activity. Results of the antimicrobial screening has shown that a majority of compounds exhibit significant antibacterial and noticeable antifungal activities, with minimum inhibitory concentrations 3.12–50 μg/mL against several microorganisms. Some of the synthesized analogs have also elicited noticeable inhibitory action against M. tuberculosis H37Rv strain. The best results are observed amongst the thiazolidinone substituted analogs. The structures of the synthesized analogs are corroborated on the basis of IR, 1H and 13C NMR, mass spectrometric and elemental analysis

Design, synthesis and antimicrobial screening of s-Triazinyl piperazine and piperidine derivatives

A series of ten 2,4,6-trisubstituted s-triazines have been synthesized selectively with nucleophilic reagents such as 4-amino benzonitrile, 8-hydroxy quinoline and different piperazine as well as piperidine substituents on the C-6 position of s-triazine ring. The title compounds were then examined for their in vitro microbial activity against 2 gram –Ve bacteria (E. Coli, P. Aeruginosa), 2 gram +Ve bacteria (S. Aerues, B. subtilis) and 2 fungal species (C. Albicans and A. niger). The most of the synthesized compounds have shown potent anti-bacterial and anti-fungal activities. Structure of final scaffolds has been affirmed by means of IR, 1H NMR, 13C NMR and elemental analysis.Keywords: 2,4,6-trichloro-1,3,5-triazine, 8-hydroxy quinoline, 4-amino benzonitrile, anti microbial activity

2-(Quinolin-4-ylthio)-1,3,4-oxadiazole derivatives: Design, synthesis, antibacterial and antifungal studies

1318-1324A series of novel <span style="mso-bidi-font-weight: bold">hybrid 2-(7-chloroquinolin-4-ylthio)-5-(substituted)-1,3,4-oxadiazole derivatives have been designed, synthesized which contains different pharmacophores like quinoline and 1,3,4-oxadiazole linked via sulfur atom. All the newly synthesized derivatives have been characterized by IR, 1H NMR, 13C NMR spectral and elemental analysis. Further, All the final synthesized scaffolds have been subjected to in vitro antimicrobial activity against several bacteria (E.coli<span style="mso-bidi-font-weight: bold">, P.aeruginosa, S.aureus, S.pyogenus) and fungi (C.albicans, A.niger, A.clavatus) using broth dilution technique. Among the compounds tested, compounds 3f substituted with coumarin analogue and 3b with amine group at second position of phenyl to oxadiazole moiety are found to be most potent. </span

Studies on Synthesis of Pyrimidine Derivatives and their Pharmacological Evaluation

1,3,4-Oxadiazoles were associated with broad spectrum of biological activities including antituberculosis, anticonvulsant, anti-inflammatory, insecticidal, antifungal, analgesic and antitumor properties. Morpholine derivatives find their wide spectrum of antimicrobial activity and exhibit anthelmintic, bactericidal and insecticidal activity. Pyrimidine derivatives are also reported to possess antibacterial, antimicrobial, antifungal, anticancer and anticonvulsant activities. Encouraged by this observations we decided to synthesised novel pyrimidine derivatives

Synthesis and Studies of 1-[2-(Aryl Amino-2-Oxo Ethyl) Amino]-4-(N-Methyl Piperazino)-Benzene Derivatives

1-[2-(Aryl Amino-2-Oxo Ethyl) Amino]-4-(N-Methyl Piperazino)-Benzene Derivatives were synthesized. The synthesized compounds were screened for their antibacterial activities against S.aures and E.coli by cup plat method. From screening result some compounds found highly active against both Gram-positive and Gram-negative bacteria while other compounds possess feeble to moderate activity

Novel s-Triazinyl Schiff Base/Chalcone Congeners: Rational, Synthesis, Antimicrobial and Anti-TB Evaluation

ABSTRACT The occurrence of Multi Drug Resistant (MDR) infectious microbial strains has been increased upto alarming level which affects the public health worldwide. To cure this problem, a library of striazinyl derivatives comprising schiff base or chalcone motif have been rationalized, synthesized and screened for their in vitro antibacterial activity against five bacterial strains (Staphylococcus aureus MTCC 96, Bacillus subtilis MTCC 441, Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 741 and Klebsiella pneumoniae MTCC 109) and four fungal strains (Aspergillus niger MTCC 282, Aspergillus fumigates MTCC 343, Aspergillus clavatus MTCC 1323, Candida albicans MTCC 183) using broth dilution technique. All the newly synthesized scaffolds were further evaluated for their in vitro anti-TB efficacy against the tubercular strain (Mycobacterium tuberculosis H37Rv) using Lowenstein-Jensen MIC method. All the derivatives were well characterized by IR, 1 H NMR, 13 C NMR, elemental analysis as well as mass spectroscopy