Chalcones as versatile synthons for the synthesis of 5- and 6-membered nitrogen heterocylces

Chalcones belong to the flavonoid family which constitutes one of the major classes of naturally occurring oxygen heterocyclic compounds. The alpha,beta-unsaturated carbonyl system of chalcones possesses two electrophilic reactive centers allowing them to participate in addition reactions via attack to the carbonyl group (1,2-addition) or involving the beta-carbon (1,4-conjugate addition), leading to the synthesis of promising bioactive heterocyclic compounds. The purpose of this review is to present a systematic survey of the most recent literature that uses chalcones in the synthesis of biologically active 5- and 6-membered nitrogen heterocycles such as pyrroles, indoles, isoxazoles, imidazoles, pyrazoles, indazoles, triazoles, tetrazoles, pyridines and pyrimidines. Efficiency, easy-to-handle and cheap reagents, alternative heating conditions and greener protocols will be highlighted. In this review we will cover the literature since the beginning of the 21st century in more than 400 publications.PEst-C/QUI/UI0062/2013 FCOMP-01-0124-FEDER-03729

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

Synthesis and characterization of phosphine substituted organometallic chalcones

The current focus in organometallic chalcones is based upon their synthesis, eloectrochemical properties, diverse biological behavior and their facet towards a new field “bioorganometallics’’ concerning both organometallic and coordination chemistry . The organometallic chalcones can be used as precursor for the synthesis of various other important biologically active heterocyclic compounds. Ferrocene based derivatives which are one of the most extensively studied among metallocenes has also been reported for their application to materials particularly in designing molecular sensors, molecular ferromagnet, electrochemical agent, molecular switch and non-linear optical material. Recently, phosphine chemistry has gained attention due to their tremendous applications and aspects in the field of bioorganometallics. In view of their enormous prospect we carried out the synthesis and characterization of phosphine substituted multimetallic organometallic chalcone. The electrochemical and biological properties of synthesized organometallic chalcone is under investigation

Exploration of the chemistry and biological properties of pyrimidine as a privileged pharmacophore in therapeutics

The pyrimidine moiety is one of the most widespread heterocycles in biologically occurring compounds, such as nucleic acids components (uracil, thymine and cytosine) and vitamin B1. Due to its prebiotic nature to living cells in biodiversity, it is an highly privileged motif for the development of molecules of biological and pharmaceutical interest. This present work deals with the exploration of chemistry and medicinal diversity of pyrimidine which might pave way to long await discovery in therapeutic medicine for future drug design

Exploration of the Chemistry and Biological Properties of Pyrimidine as a Privilege Pharmacophore in Therapeutics

The pyrimidine moiety is one of the most widespread heterocycles in biologically occurring compounds, such as nucleic acids components (uracil, thymine and cytosine) and vitamin B1. Due to its prebiotic nature to living cells in biodiversity, it is an highly privileged motif for the development of molecules of biological and pharmaceutical interest. This present work deals with the exploration of chemistry and medicinal diversity of pyrimidine which might pave way to long await discovery in therapeutic medicine for future drug design

Article Heteroaryl Chalcones: Design, Synthesis, X-ray Crystal Structures and Biological Evaluation

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X-ray analysis of different starch granules

Crystal sizes and lattice distortion parameters for root, pulse and cereal starch granules have been determined using observed X-ray diffraction reflections by Fourier method. Enthalpy for the formation of the lattice in root, pulse and cereal starches has been estimated and compared. It is found that the crystal size is normally high in root starch compared to pulse and cereal starches

Short Review on Thiazole Derivative

Thiazole is aromatic, heterocyclic organic compound that have five membered molecular ring structures C3H3NS. Thiazole was first described by Hantzch and Weber in 1887. Prop confirmed its structure in 1889. The numbering of thiazole starts from sulphur atom.  Numerous reports have appeared in the literature which highlights their chemistry and pharmacological uses. There is larger Pi-electron delocalization in thiazoles as compared to corresponding oxazoles and hence have greater aromaticity which is evidenced by the chemical shift of the ring protons in proton NMR spectroscopy indicating strong diamagnetic current. Mostly researches have maintained their interest in nitrogen and sulphur containing heterocyclic compounds through decades of historical development of organic. This paper aims to review the antimicrobial activities of thiazole during the past decades. Keywords: Thiazole, Heterocyclic compounds, Oxazoles Biological activities,&nbsp

A REVIEW ON PYRAZOLINE DERIVATIVES AS ANTIMICROBIAL AGENT

At present, there is a lot of research about the pyrazoline heterocyclic compound, its ring structure is being changed and new derivatives are being made, many of which have antimicrobial activity over the derivatives. Pyrazoline is the five-member heterocyclic ring which have two N atoms in nearby position and contains two endocyclic double bonds. Noteworthy consideration has been concentrated on pyrazolines and pyrazoline derivative due to their important pharmacological action. Some replaced pyrazolines have been stated near retain particular important pharmacological actions as antimicrobial, antifungal, antineoplastic, antidepressant, insecticidal, anticonvulsant, anti-inflammatory, antibacterial and antitumor properties