Introduction: Heterocyclic chemistry is avery important branch of organic chemistry. Heterocyclic compounds are of verymuch interest in our daily life. Many natural products, vitamins, biomoleculesand wide variety of drugs have Heterocycles existing in them. The same appliesfor biologically active compounds, such as antitumor, antibiotic,anti-inflammatory, antimalarial, antidepressant, anti-HIV, antimicrobial,antibacterial, antiviral, antifungal, antidiabetic, herbicidal, fungicidal, andinsecticidal agents which all have heterocycles in them. Some important applications in materials sciencecontains most of the heterocycles such as fluorescent sensor, plastics,dyestuff, brightening agents, information storage, and analytical reagents. Theheterocyclic ring comprises the core of the active moiety or pharmacophore1-4.
It is well known that anumber of heterocyclic compounds containing nitrogen and sulphur exhibit a widevariety of biological activities. The pyrazole scaffold has attracted a greatdeal of interest due to its contributions in biological and pharmacologicalfields. Pyrazole derivativeshave found in pharmaceuticals, agrochemicals and other applications. Thiazolenucleus is known to exhibit various pharmacological profiles such asanti-inflammatory, 5, 6 antimicrobial, 7- 9 antiviral, 10 antitumor, 11antioxidant, 12 activities etc.
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Pyrene is a polycyclic aromatic hydrocarbon (PAH) offormula is C16H10. It is aflat aromatic system consisting of fourfused benzene rings. Pyrene is a colorless solid, solid and solutionshave a little blue fluorescence 13. Pyrene forms during incompleteburning of organic materials. Pyrene was first separated from coaltar by pyrolysis of acetylene and hydrogen 14.
It is generated in a widerange of burning conditions, particularly wood burning; gasoline fuel exhaust;coal tar and asphalt; and cigarette smoke. Pyrene moiety is considered as one of the most usefulscaffolds for the construction of fluorogenic chemo-sensors for a diversity ofimportant chemical species.Pyrene shows a high fluorescence (FL) quantum yield in solution and efficientexcimer formation.
15,16. It has been used to define solvent environments dueto sensitivity of fluorescence emission spectrum to solvent polarity. Pyrenemoieties are widely used as fluorogenic units due to their relatively efficientexcimer formation and emission 17.
Pyrene has a long singlet lifetime whichallowed it to be used as the fluorophore. Also, the emission of pyrene hasvibrational band structure. Pyrene and its derivatives found in manyapplications in electronics, photovoltaic cells and sensors. Infact, pyrene exhibits electrochemicaland photophysical properties, which have results in its usage in different scientificareas. Therefore, we will try tosynthesize a new series of anchored nitrogen-containing heterocyclesincorporating pyrene moiety as fluorescent and photochromic compounds.