Hammett Spectral Correlations in some Aryl 1,3-Oxazine-4-Thione Derivatives

Abstract

A series of some aryl 1,3-oxazine-4-thione derivatives have been synthesized by 1-methyl imidazole catalyzed three component one pot synthetic method in room temperature. The purities of these thiones were studied by their physical constants and spectroscopic data. The infrared and 13 C NMR spectral data of CN and CS were correlated with Hammett substituent constants, F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituent on the spectral data was studied.Keywords: 1,3-oxazine-4-thiones; IR spectra; 13 C NMR spectra; Hammett correlation INTRDUCTIONAryl 1,3-oxazine-4-thiones are pharmaceutical important heterocycles [1,2] [21]. The spatial arrangement of protons such as cis and trans of organic stereo chemical compounds [22] were studied using NMR spectra. Currently chemists and spectroscopic researchers [23][24][25][26][27][28][29] have paid much more interest for correlation of spectral data with Hammett substituent constants. Thirunarayanan and Ravi [30] have studied the effect of substituents of some pyrazoline-1-ethanones. Substituent effects on the spectral group frequencies of 9H-fluorenayl bromides were studied by Thirunarayanan [31]. Sakthinathan et al., have investigated the effect of substituents on naphthyl based pyrazoline derivatives [32]. Sasikala et al.,[22] have evaluated the effect of substituents and antimicrobial activities of some 5-bromo-2-thienyl based pyrazolines. The spectral correlation of infrared and nuclear magnetic resonance spectra of E-imines have been predicted by Sakthinathan et. al. and Suresh et al.,[33,34]. Thirunarayanan and Sekar have investigated the substituent effects on the IR and NMR spectral frequencies of some 3-(3,4-

Spectral Correlations and Antimicrobial Activities of some 1-Pyrenyl Chalcones

“…While seeking these parameters in multi-regression, with F and R Swain-Lupton's [33] constants, they gave satisfactory correlations with the chemical shifts of (δ, ppm ) Hα and Hβ. The multi correlation equations are given in 17-20. δH α (ppm) = 7.530(±0.221) + 0.069(±0.044)σ I + 0.826(±0.566) σ R … (17) (R = 0.951, n = 9, P > 95 %) δH α (ppm) = 7.562(±0.218) + 0.006(±0.004)F + 0.693(±0.521)R … (18) (R = 0.948, n = 9, P > 90 %) δH β (ppm) = 7.950(±0.200) + 0.382(±0.040)σ I + 0.575(±0.051)σ R … (19) (R = 0.952, n = 9, P > 95 %) δH β (ppm) = 8.019(±0.195) + 0.271(±0.039)F + 0.624(±0.467)R … (20) (R = 0.950, n = 9, P > 95 %)…”

“…The Crossed-Aldol [2], Claisen Schmidt [3], Knovenagal [4] and Wittig [5] reactions are important for the synthesis of enones. Many catalyst were used for proceedings the above said reactions namely, EtOH-NaOH [6], MeOH-KOH [7], EtOH-KOH [8], MgCl 2 [5], silica-sulphuric acid [9], anhydrous zinc chloride [10], clay [11], Hydrotalcite [12], ground chemistry catalysts-grinding the reactants with sodium hydroxide [13], aqueous alkali in lower temperature [14], solid sulphonic acid from bamboo [15], barium hydroxide [16] anhydrous sodium bicarbonate [17], microwave assisted synthesis [18], flyash: water [19], fly-ash: H 2 SO 4 [20], fly-ash: PTS [21], NaOH-CTABr [22], SiO 2 -H 3 PO 4 [23], SOCl 2 [24] and sulfated titania [25]. The spectral data of these E-chalcones were useful for prediction of ground state equilibration like s-cis and s-trans conformers.…”