The reaction of 1,3-dipolar cycloaddition of 2-diazopropane 1 with enones 2a-d at 0°C, has led to Δ2-pyrazolines 4a-d. Pyrazolenines 5a-d resulted, in a good yield, from oxidation of Δ2-pyrazolines 4a-d by MnO2.
H. Hammami, Y. Ben Dhia, A. Khemiss
2-diazopropane, 1,3-dipolar cycloaddition, Δ2-pyrazolines, pyrazolenines
From the leaves of the plant Ajuga pseudoiva a new neo-clerodane diterpenoid, Hativene D, has been isolated. Its structure was established by spectroscopic means. The antifeedant activity of this compound has been studied against Egyptian cotton leafworm Spodoptera littoralis (Boisd.) (Lepidoptera) by application of the leaf disk method. This substance exhibited an interesting activity even at 1 ppm. Structure-activity relationship is discussed. The antibacterial effect of this neo-clerodane has been also tested.
H. Ben Jannet, M.H. Oueslati, A. Chaari, M.T. Martin, A. Loukaci, M.J. Simmonds, Z. Mighri
Ajuga pseudoiva, Lamiacea, clerodane diterpenoid, Hativene D, anti-insect, antibacterial
This research is a contribution to the synthesis of functionalized dibenzo-pyridino-18-crown-6 (DB-P-18-C-6). The functions bromo and nitro were fixed on the aromatic rings. New di and tri substituted derivatives of DB-P-l8-C-6 were synthesized. The substituted crowns were characterized by 1H-NMR, IR, U.V, MS and elemental analysis. Likewise, we have tested these crowns for their complexing properties for alkali cations by the determination of extraction equilibrium constants (Ke) and the complexation constants (Kc). The determination of pKa for these compounds was realized by different methods and in different solvent systems.
A. Ben Hadj Amor, F. Meganem
Dibenzo-pyridino-18-crown-6, Synthesis, Fictionalisation, Extraction, Acidity
Three compounds, previously identified in other natural sources, have been isolated for the first time from the fruit barks of Periploca laevigata (Asclepiadaceae): oleanolic acid 1, maslinic acid 2 and β-sitosterol-3-β-D-glucoside 4. β-amyrine 3 has been also re-isolated. Their structures have been established by spectroscopic procedures.
F. Hichri, O. Hammouda, H. Ben Jannet, Z. Mighri, P.J.M. Abreu
Periploca laevigata, Asclepiadaceae, Triterpenoids, Sterol, NMR
New caprolactams and related compounds were synthesized via Beckmann rearrangements and subsequent Diels-Alder additions starting from ketone oximes of isophorone derivatives. The reactions were activated by microwave irradiation and the results were compared to those obtained under conventional heating. Anyhow, microwave activation was more efficient as compared to conventional heating, every conditions equal elsewhere.
Y. El Barkaoui, A. El Louzil, A. Loupy, M. Soufiaoui, S. Fkih-Tetouani
Microwave, isophorone, caprolactames, azipines, rearrangement de Beckmann, addition de Diels-Alder
The condensation of guanidine, aminobenzimidazole and 5-amino-1,2,4-triazole with 2- dialkylaminomethylpropenenitriles constitute a highly regiospecific reaction and an original route for synthesis of new dihydropyrimidines, dihydropyrimidobenzimidazoles and dihydrotriazolopyrimidines.
F. Yaccoubi, M.L. El Efrit, H. Zantour
dihydropyrimidines, dihydropyrimidobenzimidazoles, dihydrotriazolopyrimidines
This article deals with olive oil and has for objects to study the evolution of acidic and triglyceridic composition during maturity and the interrelation between the palmitic acid (16:0) and oleic acid (C18:1) and linoleic acid (C18:2) on the one hand and between these three acids and the 12 triglycerids (LLL, OLLn, OLL, OOLn, PLL, OOL, POL, PPL, OOO, P00, PPO and SOO) of others part. The results obtained showed a stability of oleic acid, a reduction of the palmitic acid and an increase of linoleic acid during the process of maturity. They also revealed that this process is accompanied by a decrease in percentage of POL, PPL and POO and an increase of the percentage of OLL. As for links of dependence, the statistical calculations done, showed a strong relation of dependence between the palmitic acid and the two other acids combined (oleic and linoleic) (r2 = 0,952) and between the palmitic acid and the linoleic acid (r2 = 0,736 ). The linear relation between the palinitic acid and the oleic acid is rather weak (r2 = 0,36). Otherwise, these calculations revealed the very important relation of dependence existing between every fatty acid and triglycerids corresponding to it. In fact, the factors of determination are superior than. 0,84.
A. Lazez, B. Karray, M. Ayadi, M. Khlif, M. Cossentini
olive oil, maturity, fatty acids, triglycerids, relation of dependence
A new synthetic route is reported for siderophores APn having pyrocatechol groups located α to each carboxylic acid of a α,ω-linear diacid. The use of a benzyl group for protecting a phenolic hydroxide allows an easy deprotection by hydrogenolysis and gives a better yield for the multistep synthesis. An improved synthetic procedure for preparing the intermediate 2-benzyloxyphenol (pyrocatechol monobenzylether), by solid-liquid phase transfer catalysis, is reported (K2CO3, Aliquat, xylene; yield = 75%).
M. Ismaïl, A. Zinelabidine, F. Mhenni, R. Gallo
siderophores, protecting group, hydrogenolysis, ether cleavage, Phase Transfer Catalysis (PTC)
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