Spectroscopy: An Important Tool for Structural Illustration of Heterocyclic Drugs
Abstract
Spectroscopy is the investigation and measurement of spectra produced by matter interacting with or emitting electromagnetic radiation. Originally, spectroscopy was defined as the study of the interaction between radiation and matter as a function of wavelength. Now, spectroscopy is defined as any measurement of a quantity as a function of wavelength or frequency. During a spectroscopy experiment, electromagnetic radiation of a specified wavelength range passes from a source through a sample containing compounds of interest, resulting in absorption or emission. During absorption, the sample absorbs energy from the light source. During emission, the sample emits light of a different wavelength than the source’s wavelength.
In absorption spectroscopy, the sample’s compounds are excited by the electromagnetic radiation provided by a light source. Their molecules absorb energy from the electromagnetic radiation, become excited, and jump from a low energy ground state to a higher energy state of excitation. A detector, usually a photodiode, on the opposite side of the sample records the sample’s absorption of wavelengths, and determines the extent of their absorption. The spectrum of a sample’s absorbed wavelengths is known as its absorption spectrum, and the quantity of light absorbed by a sample is its absorbance.
Each molecule within a sample will only absorb wavelengths with energies corresponding to the energy difference of the present transition. In simpler terms, this means that a molecule that jumps from ground state 1 to excited state 2, with an energy difference of ΔE, will allow other wavelengths to pass through until it can absorb radiation from a wavelength that corresponds to ΔE. Light that passes through to the photodiode without any absorption is called Stray Radiant Energy, or stray light. Absorption that occurs due to an energy difference between the two states is called an absorption line, and a collection of absorption lines creates an absorption spectra. The frequency of each absorption line in an absorption spectra tells us about the sample’s molecular structure, and can be influenced by factors such as stray light, environmental temperature, and electromagnetic fields.
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2. Valverde MG, Torroba T (2005) Sulfur-Nitrogen Heterocycles. Molecules 10: 318-320.
3. Liu RS (2001) Synthesis of oxygen heterocycles via alkynyltungsten compounds. Pure Appl Chem 73: 265.
4. Abdel-Hafez SH (2008) Selenium containing heterocycles: Synthesis, Dnti-inflDmmDtory, analgesic and anti-microbial activities of some new 4- cyanopyridazine-3 (2H) selenone derivatives. Eur J Med Chem 43: 1971.
5. Mittal A (2009) Synthetic Nitroimidazoles: Biological Activities and Mutagenicity Relationships. Sci Pharm: 77: 497-520.
6. Nagalakshmi G (2008) Synthesis, antimicrobial and DntiinflDmmDtory activity of 2, 5-disubstituted-1, 3, 4-oxadiazoles. Indian J Pharm Sci 70: 49-55.
7. Nekrasov DD (2001) Biological Activity of 5-and 6-Membered Azaheterocycles and Нeir Synthesis from 5-Aryl-2, 3-Dihydrofuran-2, 3- diones. Chem Heterocycl Compd: 37: 263-275.
8. Sperry JB, Wright DL (2005) Furans, thiophenes and related heterocycles in drug discovery. Curr Opin Drug Discov Devel 8: 723-740.
9. Polshettiwar V, Varma RS (2008) Greener and expeditious synthesis of bioactive heterocycles using microwave irradiation. Pure Appl Chem 80: 777.
10. Katritzky AR (1992) Heterocyclic chemistry: An academic subject of immense industrial importance. Chem Heterocycl Compd 28: 241-259.
11. Katritzky AR, Drum CA (1984) In Comprehensive Heterocyclic Chemistry. In: Katritzky AR, Rees CW (eds.), Pergamon Press, Oxford, New York, USA, p. 47.
12. Grimmett M, Ross M (1997) Imidazole and benzimidazole synthesis. Academic Press, Massachusetts, United States.
13. Brown EG (1998) Ring Nitrogen and Key Biomolecules: Нe Biochemistry of N-Heterocycles. Kluwer Academic Press, Netherland.
14. Pozharskii AF, Soldatenkov AT, Katritzky AR (1997) Heterocycles in life and society. John Wiley and Sons, UK.
15. Gilchrist TL (1985) Heterocyclic Chemistry. Нe Bath Press, UK.
16. Congiu C, Cocco MT, Onnis V (2008) Design, synthesis, and in vitro antitumor activity of new 1, 4-diarylimidazole-2-ones and their 2-thione analogues. Bioorg Med Chem Lett 18: 989.
17. Venkatesan AM, Agarwal A, Abe T, Ushirogochi HO, Santos D, et al. (2008) 5, 5, 6-Fused tricycles bearing imidazole and pyrazole 6- methylidene penems as broad-spectrum inhibitors of β-lactamases. Bioorg Med Chem 16: 1890-1902.
18. Nakamura T, Kakinuma H, Umemiya H, Amada H, Miyata N, et al. (2004) Imidazole derivatives as new potent and selective 20-HETE synthase inhibitors. Bioorg Med Chem Lett 14: 333.
19. Han MS, Kim DH (2001) (وٴect of zinc ion on the inhibition of carboxypeptidase A by imidazole-bearing substrate analogues. Bioorg Med Chem Lett 11: 1425.
20. Emami S, Foroumadi A, Falahati M, Lotfali E, Rajabalian S, et al. (2008) 2-Hydroxyphenacyl azoles and related azolium derivatives as antifungal agents. Bioorg Med Chem Lett 18: 141.
21. Ujjinamatada RK, Baier A, Borowski P, Hosmane RS (2007) An analogue of AICAR with dual inhibitory activity against WNV and HCV NTPase/ helicase: synthesis and in vitro screening of 4-carbamoyl-5-(4, 6- diamino-2, 5-dihydro-1, 3, 5-triazin-2-yl) imidazole-1-β-dribofuranoside. Bioorg Med Chem Lett 17: 2285.
22. Shingalapur RV, Hosamani KM, Keri RS (2009) Synthesis and evaluation of in vitro anti-microbial and anti-tubercular activity of 2-styryl benzimidazoles. Eur J Med Chem 44: 4244.
23. Vijesh AM, Isloor AM, Telkar S, Peethambar SK, Rai S, et al. (2001) Synthesis, characterization and antimicrobial studies of some new pyrazole incorporated imidazole derivatives. Eur J Med Chem 46: 3531.
24. Venkateswarlu P, Sunkaraneni SB (2005) Polyheterocyclic systems: Synthesis and biological activity of novel heterocyclic annelated compounds from 2, 3, 4, 5-tetrahydro-1-benzazepin-5-one. Indian J Chem 44B: 1257.
25. James GC, Sherman N (1992) In: Microbiology: A Laboratory Manual. (3rd edn.) Нe Benjamin/Cummings Publishing Company, California.
26. Noolvi M, Agrawal S, Patel H, Badiger A, Gaba M, et al. (2011) Synthesis, antimicrobial and cytotoxic activity of novel azetidine-2-one derivatives of 1H-benzimidazole. Arabian J Chem 7: 219-226.
27. Ozkay Y, Isikdag I, Incesu Z, Akalin G (2010) Synthesis of 2-substitutedN-[4-(1-methyl-4, 5-diphenyl-1H-imidazole-2-yl) phenyl] acetamide derivatives and evaluation of their anticancer activity. Eur J Med Chem 45: 3320.
28. Zhang D, Wang G, Zhao G, Huo L (2011) Synthesis and cytotoxic activity of novel 3-(1H-indol-3-yl)-1H-pyrazole-5-carbohydrazide derivatives. Eur J Med Chem 46: 5868-5877.
29. Kamal A, Prabhakar S, Ramaiah MJ, Reddy PV, Reddy CR, et al. (2011) Synthesis and anticancer activity of chalcone-pyrrolobenzodiazepine conjugates linked via 1, 2, 3-triazole ring side-armed with alkane spacers. Eur J Med Chem 46: 3820.
30. Zhang Y, Zhong H, Wang T, Geng D, Zhang M (2012) Synthesis of novel 2, 5-dihydrofuran derivatives and evaluation of their anticancer activity. Eur J Med Chem 48: 69.
31. Yong A, Liang YJ, Liu JC, He HW, Chen Y, et al. (2012) Synthesis and in vitro antiproliferative evaluation of pyrimido[5,4-c]quinoline-4-(3H)-one derivatives. Eur J Med Chem 47: 206.
32. Chitra S, Paul N, Muthusubramanian S, Manisankar P, Yogeeswari P, et al. (2011) Synthesis of 3-heteroarylthioquinoline derivatives and their in vitro antituberculosis and cytotoxicity studies. Eur J Med Chem 46: 4897.
33. Kurumurthy C, Rao PS, Swamy BV, Kumar GS, Rao PS, et al. (2011) Synthesis of novel alkyltriazole tagged pyrido [2, 3-d] pyrimidine derivatives and their anticancer activity. Eur J Med Chem 2011: 46, 3462.
34. Balbi A, Anzaldi M, Macciò C, Aiello C, Mazzei M, et al. (2011) Synthesis and biological evaluation of novel pyrazole derivatives with anticancer activity. Eur J Med Chem 46: 5293.
35. Abou-Seri SM (2010) Synthesis and biological evaluation of novel 2, 4′-bis substituted diphenylamines as anticancer agents and potential epidermal growth factor receptor tyrosine kinase inhibitors. Eur J Med Chem 45: 4113.
