Organic Chemistry

The ultrasonic velocity, density and viscosity have been measured for the binary liquid mixture of polyvinyl alcohol+ water has been measured as a function of the composition of 303,308,313and318 K. The experimental data have been used to calculate some parameters namely, acoustic impedance (z), adiabatic compressibility (?), intermolecular free length (Lf), and relative association (RA). The results are discussed and interpreted in terms of structural and specific interactions that predominated by intermolecular hydrogen bonding.

A Coumarin derivative, 4-ethoxy-6-((hydroxymethoxy)methyl)-2H-chromen-2-one, was isolated from the stem bark of Jatropha multifida, and its structure was elucidated from UV, IR, MS and 2D NMR spectra. The compound has 1-oxygenated structure with a lactone moiety.

Ten new heterocyclic moiety containing Schiff bases have been synthesized by the condensation of 4,5-diazafluoren-9-one with substituted amines by using SnCl₂ as a catalyst under solvent free condition. The Schiff bases were obtained in good yields and easy to isolate. Some synthesized products were characterized by IR, NMR and MASS and also tested for antibacterial activities by disc diffusion method.

A simple, efficient and cost-effective method has been developed for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones by a one-pot three component cyclocondensation reaction of ethyl aceteoacetate, aromatic aldehydes, and urea/thiourea using sodium nitrate as catalyst. The significant advantages of the present protocol are simplicity, high yields, no chromatographic separation, eco-friendliness and recoverability of the catalyst.

Nigeria is one of the countries of the world with a variety of oil seeds, therefore the potential of Nigeria leading Africa, and the world at large, in the area of seeds oil production was examined by evaluating the oil yield and physicochemical qualities of oil extracted from Citrullus lanatus from the southern region of the country. The lipid content of Citrullus lanatus seeds was found to be 57.26%. The iodine, saponification, acid, free fatty acid, peroxide, specific gravity, refractive index and pH, were analysed using standard procedures and values were found to be 114.94g I₂/100g, 220.19 mgKOH/g, 7.09 mgKOH/g, 4.512%, 20.00 meq/kg, 0.913, 1.35, and 4.45 respectively. The oil contains five main fatty acids: palmitic, stearic, oleic, linoleic are linolenic acids, but the most abundant fatty acid is linoleic with a value of 64.15% which is used industrially as a drying agent in gloss paint. Due to their high oil yield and abundance, oils from Citrullus lanatus seeds may be considered as Nigeria potential asset for soap production and other industrial applications.

An efficient one-pot protocol to generate 4-arylmethyleneisoxazol-5-one derivatives from ethyl acetoacetate, hydroxylamine hydrochloride, and various aromatic aldehydes using sodium azide catalyst in water as environmentally benign solvent has been developed.

Comparative study of O-butylation of phenols under Liquid-Liquid biphasic versus solid-liquid-liquid and Liquid-Liquid-Liquid triphasic phase transfer catalysis has been carried out. 1-Butyl bromide was used as an alkylating agent. Tetrabutyl ammonium hydrogen sulphate was used as Phase transfer catalyst. The rates of reaction were enhanced under the triphasic PTC as compared to the Liquid-Liquid PTC.

Mild and efficient synthesis of 5, 7-dihydroxy-6-methoxy-2-phenyl-4H-chromen-4-one (Oroxylin A) has been reported. MEM is used as protecting group to get Oroxyline A. Screening of protecting groups and solvents system are described in detail. Optimal reaction conditions towards achieving maximum selectivity are discussed. Oroxylin A is characterized by NMR and Mass spectroscopy.

Some aryl chalcones [E-2-Propen-1-ones] have been synthesized using Fly-ash:water catalyzed solvent free Crossed-Aldol reaction between aryl methyl ketones and aryl aldehydes. The yield of chalcones is more than 60%. The purities of these chalcones are checked by their physical constants and spectral data published literature in earlier. The insect antifeedant activities of chalcones have been studied using 4th instar larvae Achoea Janata L.

In this paper, the synthesis of 2-alkenylthieno[3,2-b]thiophene by direct [Pd]-[Cu]-[Ag] catalyzed C-H activation of thieno[3,2-b]thiophene with various alkenes was described. The structures of products 3a-f as well as the site-selectivity of the Heck-type cross-coupling reaction were clarified by NMR and MS analyses.