The condensation of F-alkyl hydrazinoalcohols 1 and N-Acyl, F-alkyl hydrazides 6 with β-diketones 2 allowed a convenient synthesis of new pyrazoles 3, 4, 7 et 8.
I. Mastouri, A. Baklouti
hydrazinoalcohols, hydrazide, F-alkylated pyrazoles
The ethanolic extract of Aloe vera leaf skin was fractionated by liquid-liquid partition using hexane, ethyl acetate, chloroform-ethanol and butanol. The total phenolic content of the four different fractions were determined by Folin-Ciocalteu method and their antioxidant activity was essayed through some in vitro models such as the antioxidant capacity by phosphomolybdenum method, β-carotene bleaching method, radical scavenging activity using 2,2-diphenyl-1-picryl hydrazyl (DPPH) assay and reducing power assay. The chloroform-ethanol fraction showed the highest total phenolics (40.500 ± 0.041 µg gallic acid equivalents/g of extract), the highest scavenging activity and the greatest reducing power, followed by ethyl acetate, butanol and hexane extracts. However, the hexane fraction showed the highest antioxidant capacity (471.300 ± 0.013) and the highest antioxidant activity coefficient (AAC) by the β-carotene bleaching method.
S. Miladi, M. Damak
Antioxidant activity, Aloe vera leaf skin, total phenols, DPPH, Reducing power, β-carotene
New pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidines 3a-i have been synthesized through the cyclocondensation of 5-amino-4-iminopyrazolopyrimidines 2a-c and a series of electrophilic species incorporating one carbon unit.
A. Romdhane, B. Trimeche, S. Hammami, R. Gharbi, M.A. Hamza, Z. Mighri
5-amino-4-iminopyrazolopyrimidines, electrophilic species, pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidines
The essential oil composition of the leaf of Juniperus phoenicea from region of Medenine (The south of Tunisia) was investigated by GC, GC-MS. 27 constituents were identified correspond to 84.63% of the total oil. The major components are α-Pinene (59.11%), Linalool (3.3%), Germacrene D (1.55%) and Germacrene B (3.22%). Antioxidant action of this essential oil is proved in vegetal oil (soybean) and was effective in stabilizing lard against oxidation. Its activity is compared to that of δ-tocopherol. This oil has been tested for antimicrobial activity against two bacteria (Klebsiella oxytoca, Lactobacillus plantarum), yeast (Saccharomyces cereviseae) and fungi (Geotrichum candidum). Insecticidal properties of Juniperus phoenicea essential oil were investigated against Tribolium confusum insect pest of stored grains. This oil exhibited an interesting antifeedant activity. A preliminary study showed that this oil presented high toxicity against this insect.
N. Bouzouita, F. Kachouri, M. Ben Halima, M.M. Chaabouni
Juniperus phoenicea, Essential oil, Antioxidant activity, Antimicrobial activity, Insecticidal activity
Asymmetric hydrogenations of an achiral β-keto ester using a chiral diphosphine-ruthenium catalyst to set the hydroxyl function in a stereo controlled manner were used in key-step towards the total synthesis of both enantiomers of secondary alcohols with excellent enantioselectivity (>99% ee) and high yields.
R. Touati, B. Ben Hassine
Asymmetric hydrogenation, atmospheric pressure, β-hydroxy esters, 1,3-diols, monotosylate 1,3-diols, secondary alcohols
The butanolic extract of Eryngium dichotomum Desf. aerial parts afforded a Cyclohexenone glycoside 1, flavone glycoside : Naringenine 7-O-α-L-Rhamnopyranosyl-(1→2)-O-β-D-glucopyranoside 2, Sugar: β-Dfructofuranose 3, 2-O-methyl-α-D-fructofuranose 4, Sucrose 5 and D-mannitol 6. Their structures were principally elucidated by spectroscopic procedures and chemical data. These natural substances are signalled for the first time in Eryngium dichotomum Desf.
S. Nacef, H. Ben Jannet, M.A. Hamza, Z. Mighri
Cyclohexenone glycoside, Flavone glycoside, Sugar, Eryngium dichotomum, NMR
Substitution reaction of E-branched Baylis-Hillman bromides with sodium benzenesulfinate in absolute ethanol at room temperature, produces in SN2 process and high stereoselectivity, the corresponding allyl phenyl sulfinates in good yields.
S. Khamri, T. Turki, H. Amri
Baylis-Hillman derivatives, nucleophilic substitution, allyl phenyl sulfones
Our understanding of the properties of porous crystalline materials is largely based on studies of zeolites and other inorganic substances. The advent of new analogues, including purely molecular networks, has created opportunities to base knowledge of porous materials on a broader foundation. We have used permeable molecular crystals of tetrakis(3,5-dihydroxyphenyl)silane (1) to show how the exchange of guests depends on both structure and morphology. Specifically, exchange is faster in polymorphs with wider channels and in crystalline morphologies with well-developed faces that cut the channels.
O. Saied, T. Maris, S.F. Zalzal, J.D. Wuest
Crystal engineering, porous molecular networks, guests exchange, polymorphism, hydrogen bond
Rss feed of the category