Organic Chemistry

Pulverized leaves of red and yellow varieties of Caesalpina pulcherrima yielded 0.50 and 0.52% v/w of essential oils on hydrodistillation. GC and GC-MS analyses of the oils revealed the presence of fifty eight and fifty three compounds in the oil of red and yellow varieties respectively. Percentage compositions of oxygenated monoterpenes in the oil of red and yellow varieties were 70.4 and 85.1%. Sesquiterpenes constituted 28.8% of the leaf oil of red variety, while 5.1% of the oil of yellow variety was sesquiterpenes. The principal constituents of the oil of red variety were; ?-terpinene (44.4%), germacrene B (14.3%), myrcene (5.6%), allo-ocimene (5.9%), ?-caryophylene (5.1%) and ?-pinene (4.2%). Major compounds identified in the oil of yellow variety were; citronellal (58.0%), geranial (17.5%), ?-caryophylene (5.1%), linalool (2.5%) and ?-terpineol (2.3%). With the abundance of ?-terpinene and citronellal in the oils of red and yellow varieties, the oils are of ?-terpinene and citronellal chemotypes respectively.

The effects of substituents and solvents have been studied through the absorption spectra of nearly twelve meta,para and ortho-substituted N-Pheny maaleimide in the range of 200-400 nm. The effects of substituents on the absorption spectra of compounds under investigation are interpreted by correlation of absorption frequencies with simple and extended Hammett equations. With the help of Kamlet equation the effect of solvent polarity and hydrogen bonding on the absorption spectra are interpreted and the results are discussed.

During the synthesis of bis - benzothiazols via condensation of 2-aminothiophenol and oxalic, malonic acids an interesting product was obtained during the workup of the reaction products, which upon characterization by spectroscopic methods was found to be bis-(2-aminophenyl) disulfide (NH2PhSSPhNH2).

The novel ligand, 5-((N,N-diphenylamino)methyl)-8-hydroxyquinoline (DPMHQ) was synthesized by reaction of 5-chloromethyl-8-hydroxyquinoline (CMQ) hydrochloride with N,N-diphenylamine. Metal complexes of DPMHQ were synthesized with Cu(II), Co(II), Ni(II), Mn(II), Zn(II) and Cd(II) salts. The ligand DPMHQ and all its metal complexes were further investigated for elemental content, IR-NMR spectral features, metal: ligand ratio and magnetic properties. The samples were also screened for antifungal activities.

Aqueous media containing heavy metals from industries are directly or indirectly discharged into the environment to cause pollution and threat to human life. The bio-polymer chitin was synthesised using local snail shell to study the adsorption of lead, zinc and nickel from aqueous solution. The synthesis of chitin involves the following stages: (i) pre-concentration, (ii) demineralization, (iii) deprotonization and (iv) deacetylation. Chitin is characterized using analytical technique such as Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron microscope (SEM) and X-ray fluorescence (XRF) to confirm the presence of chitin. This study shows the effect of pH, time, and adsorbent dosage removal efficiency of the metals in solution. The concentrations of Pb2+, Ni2+ and Zn2+ absorbed under different conditions was evaluated using atomic adsorption spectroscopy (AAS). The result shows that the optimum pH adsorption for Pb2+, Ni2+ and Cu2+ using chitin was found to be at pH 2 for the all metals (Pb2+, Ni2+ and Zn2+) with percentage removal efficiency (92.5%, 82.4%, 80%). The synthesized chitin has a potential of an adsorbent for the removal of heavy metals in aqueous solution.

Cyclotriphosphazenes are prominent inorganic N-heterocycles.They consist of six-membered ring structures of alternating phosphorus and nitrogen atoms. The tetravalent phosphorus atoms carry two exocyclic substituents, which can be widely varied enabling fine-tuning of the size and shape of the molecular periphery. This study involved the synthesis and characterization of hexa (diethanolamino) cyclotriphosphazene by an enveremently and friendly system catalyst consist of clay layered called Maghnite-H+ (Algerian MMT) and diethyl ether. The effect of different synthesis parameters such as amount of catalyst, effect of time, temperature and solvent are discussed.

Osthol, 7-methoxy-8-(3-methylbut-2-enyl) coumarin, was isolated from the root parts of Prangos pabularia and was subjected to modification in the isopentenyl side chain to get an aldehyde 2- Methyl-4-(7-methoxy-2-oxo-2H-chromen-8-yl)-but-2-en-1-al (1). The structures of osthol and compound 1 were elucidated on the basis of MS, IR, 1H and 13C-NMR spectroscopy. Compound 1 on bio-evaluation displayed significant antimicrobial and antifungal activity.

The 4-benzylidene-2-(4-methoxyphenyl)oxazol-5(4H)-one (B) has been prepared from cyclocondensation reaction between hippuric acid (A) with p-anisaldehyde. A series of 4-benzylidene-1-(substitued-2-benzothiazolyl)-2-(4-methoxyphenyl)-1H-imidazol-5(4H)-one (D1-6) have been synthesized from 2-amino substituted benzothiazole (C1-6) by condensation reaction with 4-benzylidene-2-(4-methoxyphenyl)oxazol-5(4H)-one (B). The synthesized compounds were characterized by IR, 1H-NMR, 13C-NMR and Mass spectral data. All the compounds were screened for their antibacterial and antifungal activities.

A highly efficient and expedient protocol for the synthesis of hydrazones catalyzed by citric acid is investigated via reaction of hydrazine hydrate with different carbonyl compounds. The use of inexpensive, non-hazardous easily available citric acid as a catalyst for the synthesis hydrazones employing grinding technique is reported. The structures of the synthesized compounds are established on the basis of physical, chemical and spectral data.

ABSTRACT A series of anthracene-based microporous polymers (AMPs) bridged by imide links were successfully prepared by conventional nucleophilic substitution reaction between several 9,10-dihydro-9,10-ethanoanthracenes and cheaper 2,3,5,6-tetrachlorophalonitrile (instead of fluoro-monomer)1. AMPs display a BET surface area in the range of 811-988 m2 g–1, and reversibly adsorb 1.59 wt. % H2 at 1.09 bar/77 K. The enhanced microporosity, in comparison to other organic microporous polymers prepared from (5,5’,6,6’-tetrahydroxy-3,3,3’,3’-tetramethylspirobisindane)2 originates from the macromolecular shape of framework, as dictated by the anthracene units, which helps to reduce intermolecular contact between the extended planar struts of the rigid framework. The impressive hydrogen adsorption capture of these materials verified by Horvath?Kawazoe (HK) and NLDFT analyses of low-pressure nitrogen adsorption data.