Abstract: Background: The synthesis of novel heterocyclic derivatives has attracted considerable attention. The explosive growth of heterocyclic chemistry is emphasized by the large number of research publications, monographs, and reviews. The heterocyclic organic compounds are extensively disseminated in natural and synthetic medicinal chemistry and are vital for human life. Looking at the previous studies on quinazolinones derivatives, only limited informationis available on their mass spectral along with the preparation of novel quinazolin-4-(3H)-one derivatives. Objective: Objective of this study, was to synthesize a novel 2-Methyl-6, 7-dimethoxy-quinazolin-4-one was synthesized via the reaction between 2-Methyl-6, 7-dimethoxy-benzo-1,3-oxazin-4-one andhydrazine hydrate and study their electron impact ( EI ) mass spectral fragmentation. Method: The condensation of 2-amino-methyl-4, 5-dimethoxybenzoate with acetic anhydride yielded the cyclic compound 2-methyl-4, 5-disubstituted-1, 3-benzo-oxazine-4-one which further produce a novel 2,3-disubstituted quinazolin-4 ones via the reaction with hydrazine hydrate. The compounds synthesized were unequivocally confirmed by means of Infrared, Nuclear Magnetic Resonance (1H and 13C), Gas Chromatography Mass Spectrophotometer and Elemental analysis. Discussion: The molecular ion of m/z 235 fragment to give m/z 220 by loss of –NH group. The ion of m/z 220 was broken to give m/z 206 by losing CH2 group and fragment to m/z 177 by loss of HCO. This fragmented to m/z 162 by loss of –CH3 group and then m/z 136 by loss of CN group. The loss of O gave m/z 120 which fragment to give m/z 93 by loss of –HCN and finally gave m/z 65 by loss of CO group. Conclusion: The electron impact ionization mass spectra of compound 2show a weakmolecular ion peak and a base peak ofm/z 235resulting from a cleavage fragmentation. Compound 2 give a characteristic fragmentation pattern. From the study of the mass spectra of compound 2, it was found that the molecular ion had fragmented to the m/z 220. The final fragmentation led to ion of m/z 93 and ion of mass m/z 65, respectively.Abstract: Background: The synthesis of novel heterocyclic derivatives has attracted considerable attention. The explosive growth of heterocyclic chemistry is emphasized by the large number of research publications, monographs, and reviews. The heterocyclic organic compounds are extensively disseminated in natural and synthetic medicinal chemistry and are vit...Show More
Abstract: The aim of this study was to determine the thermal stability and shelf life of the extract together with the influence of extract concentration, temperature and pH variation of the acidic medium on the inhibition efficiency using 1.0 M Sodium hydroxide. The dried plant samples were ground, sieved using 0.25µm and then extracted with methanol using maceration method. The phytochemical constituents were analyzed using appropriate methods. The phytochemicals detected were: Alkaloid, saponin, flavnoid, tannin, terpenoid, steroid and cardiac glycoside. Weight loss experiment was performed to ascertain the stability and shelf life of the extract at different storage temperature and time respectively while polarization experiment was used to study the behaviour of the extract on mild steel corrosion at varying concentration of the extract, pH and temperature of the acidic media. It was found that the stability of the extract inhibition efficiency was affected by the mode of storage and the inhibition efficiency decreases with increase in storage temperature of the extract. The life span of the extract was found to be 60 days from its production stage, after this, there was reduction in the inhibition efficiency of the extract. Moreso, the corrosion rate of the mild steel in 1.0 M HCl, monitored by electrochemical measurement revealed that the corrosion rate decreases with increase in the pH, decrease in temperature and increase in concentration of the extract in the acidic solution.Abstract: The aim of this study was to determine the thermal stability and shelf life of the extract together with the influence of extract concentration, temperature and pH variation of the acidic medium on the inhibition efficiency using 1.0 M Sodium hydroxide. The dried plant samples were ground, sieved using 0.25µm and then extracted with methanol using ...Show More
Abstract: Theoretical study using mathematical analysis supported by Matlab code was created, for Silicon dioxide (SiO2) thin films on various substrate materials (Aluminium, quartz, and silicon), and different thicknesses. Reflectance and transmittance of the (SiO2) thin film is strongly dependent on the electromagnetic wavelength. Many physical results were obtained. The results obtained serve as an illustration of the feasibility of simple techniques in measuring precisely the reflectance and absorptance of the (SiO2) thin film with an error not exceeding 0.1%. The reflectance and absorptance characteristics of multilayer thin film are strongly dependent on the wavelength of the electromagnetic waves. The effects of various substrate materials on the reflectance characteristics have been investigated by evaluating the reflectance curves of SiO2 thin films with thickness in the range of (100-1000) nm. The amplitude and periodicity of reflectance and absorptance changed with wavelength. Also the periodicity of this variety change with the film thickness and with the substrate material. In multilayer thin-film devices, the amount of light reflected at each interface can be adjusted by adjusting many factors like film thickness and substrate materials. beams phase can be adjusted by changing the layer thickness. There are thus two parameters associated with each layer, thickness and refractive index difference between film and substrate materials, which can be chosen to give the required performance.Abstract: Theoretical study using mathematical analysis supported by Matlab code was created, for Silicon dioxide (SiO2) thin films on various substrate materials (Aluminium, quartz, and silicon), and different thicknesses. Reflectance and transmittance of the (SiO2) thin film is strongly dependent on the electromagnetic wavelength. Many physical results wer...Show More
