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The essential oils of six Myrtaceae species were investigated for their chemical composition and antimicrobial activity. The volatile oils were characterized by four common components i-e α-pinene, 1,8cineole, p-menth-1-en-8-ol and caryophyllene. The Eugenia jambolana essential oil was found rich in α-pinene (54.74%) followed by Callistemon citrinus (34.19 %), Myrtus communis (30.73 %), Melaleuca genistifolia (10.19 %) and Melaleuca alternifolia (4.47 %). Callistemon citrinus contained 1,8-cineole in appreciable amount (28.85 %) followed by Melaleuca alternifolia (26.35 %) and Myrtus communis (20.00 %). Melaleuca genistifolia oil contained highest concentration of p-menth-1-en-8-ol (14.66 %) among oils while Callistemon citrinus and Myrtus communis contained p-menth-1-en-8-ol in comparable amounts (10.69 and 9.68 %) respectively. Syzygium caryophyllatum had high content of caryophyllene (96.42 %) while it is found in minor amounts in other selected species (0.01-2.23 %). All the oils showed good antimicrobial activity against all tested microorganisms. Eugenia jambolana exhibited high antibacterial activity among the oils whereas Syzygium caryophyllatum showed hightest activity against all tested fungal strains. TEOP 18 (4) 2015 pp 950 -956 950

The root-infecting fungi can be controlled by pelleting seeds with biocontrol agents as it is safe and effective method. Additionally, plant growth was promoted more by this method. © 2015 Society of Chemical Industry.

Apart from its numerous biological activities like antidiabetic, anti-inflammatory, antimicrobial, pyrazine moiety plays an important role in luminescent materials. Its role in luminescent materials is due to its highly electron deficient nature specially when it is in the centre along the mainstay of extended π-conjugated systems. Similarly, new liquid crystalline compounds are being made constantly where the central benzoaromatic moiety is being replaced with the heterocycles including pyrazine due to their more variable nature. Pyrazine derivatives can also be used in supramolecular assemblies due to their efficient hydrogen bonding, protonation and complexation properties. Keeping in view the enormous applications of pyrazine derivatives we planned to synthesize new extended iminobenzoates with pyrazine moieties at the terminal positions. The planned iminobenzoates with terminal pyrazine moieties were prepared following standard procedures. The pyrazine-2-carbohydrazide (1) and 5-methylpyrazine-2-carbohydrazide (2) were prepared by refluxing their methyl esters with hydrazine hydrate in methanol. The esters (3a–3f) were synthesized by reacting 4-hydroxybenzaldehyde with differently substituted acid halides in tetrahydrofuran in the presence of triethyl amine. The target compounds that is, iminobenzoates with the pyrazine moieties at terminal positions (4a–4l), were obtained in good to excellent yields by the reaction of the hydrazides with the esters at reflux. The synthesized compounds were fully characterized using different spectroanalytical techniques including FT-IR, NMR, Mass, elemental analysis and single crystal X-ray diffraction analysis. The paper describes the synthesis of novel iminobenzoates following easy methods while utilizing commercially available starting materials. The synthesized iminobenzoates may possibly be converted to compounds with luminescent and liquid crystalline properties after making suitable changes to the pyrazine moieties. Properly substituted pyrazines on both sides, capable of further suitable extensions, may result in compounds with such properties.

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