Noureddine Mazoir

Bioactive triterpene derivatives from latex of two Euphorbia species

We have investigated the antifeedant and toxic effects of 23 semisynthetic terpenoid derivatives obtained through chemical modifications of the major components of Euphorbia resinifera (alpha-euphol and alpha-euphorbol) and E. officinarum (obtusifoliol and 31-norlanostenol) latex on several insect species (Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi), their selective cytotoxicity on insect Sf9 and mammalian CHO cells and their phytotoxic effects on Lactuca sativa. The conversions focused mainly on positions 3,7,11, and 24 with several oxidizing agents. A total of 18 compounds affected S. littoralis growth (IGR). Our results support the importance of the C-3 substituent, suggest the involvement of the C-7 substituent and indicate that the C-3 hydroxyl is not essential for the IGR effect. Overall, Sf9 cells were more sensitive to the active compounds than CHO cells. All of these compounds had non selective moderate phytotoxic effects on radicle elongation of L. sativa.

Optimization of Allylic Oxidation of (1S,3R,8R)‐2,2‐Dichloro‐3,7,7,10‐tetramethyltricyclo[6,4,0,01,3]dodec‐9‐ene

Abstract The allylic oxidation of (1S,3R,8R)‐2,2‐dichloro‐3,7,7,10‐tetramethyltricyclo[6,4,0,01,3]dodec‐9‐ene into the corresponding enone with N‐bromosuccinimide (NBS), CrO3 and t‐BuOOH has been studied. A good yield and high selectivity were obtained in the presence of t‐BuOOH and a copper catalyst.

Antileishmanial and antitrypanosomal activity of triterpene derivatives from latex of two Euphorbia species.

The in vitro activity on Leishmania infantum promastigotes and Trypanosoma cruzi epimastigotes of 25 semisynthetic terpenoid derivatives has been evaluated. These compounds were obtained through chemical modifications of the major components of Euphorbia resinifera (α-euphol and α-euphorbol) and Euphorbia officinarum (obtusifoliol and 31-norlanosterol). Leishmaniasis and Chagas´ disease are major worldwide health problems. The drugs of choice for their treatment are still problematic in both cases, and therefore there is an urgent need to discover new drugs with high activity and low side effects. Natural products have become a key source of new drugs in the last years. The genus Euphorbia has been the subject of abundant phytochemical and pharmacological research because of its potential medical applications, but the antiparasitic effects of derivatives from plants of this genus are still unknown. Our results showed that 76% and 64% of the test compounds had antiparasitic effects on L. infantum and T. cruzi, respectively. The different activities on both parasites, especially their moderate effects on mammalian cells, indicate an interesting selective toxicity.

N-[4-Acetyl-5-methyl-5-(2-p-tolyl­prop­yl)-4,5-dihydro-1,3,4-thia­diazol-2-yl]acetamide

The title heterocyclic compound, C17H23N3O2S, was synthesized from 4-(4-methylcyclohex-3-enyl)pent-3-en-2-one, which was isolated from Cedrus atlantica essential oil. The thiadiazole ring adopts a flattened envelope conformation, with the flap sp 3-hybridized C atom lying 0.259 (1) Å out of the plane of the other four atoms. The screw-related molecules are linked into chains along the b axis by intermolecular N—H⋯O hydrogen bonds.

N-[4-Acetyl-5-isobutyl-5-(2-p-tolyl­prop­yl)-4,5-dihydro-1,3,4-thia­diazol-2-yl]acetamide ethyl acetate hemisolvate

The racemic title compound, a new terpenoid, C20H29N3O2S·0.5C4H8O2, was synthesized from Cedrus Atlantica essential oil. The compound crystallizes with a disordered ethyl acetate solvent molecule. The thiadiazole ring is almost planar, with a maximum deviation from the mean plane of 0.015 (2) Å for the C atom connected to the isobutyl group and has a puckering amplitude of 0.026 (2) Å. The dihedral angle between the benzene and thiadiazole rings is 18.32 (8)°. The crystal packing involves intermolecular N—H⋯O hydrogen bonds.

(±)-N-[4-Acetyl-5-methyl-5-(4-methyl­cyclo­hex-3-en­yl)-4,5-dihydro-1,3,4-thia­diazol-2-yl]acetamide

The new title thiadiazole compound, C14H21N3O2S, was semi-synthesized starting from 1-(4-methylcyclohex-3-enyl)ethanone, a natural product isolated from Cedrus atlantica essential oil. The stereochemistry has been confirmed by single-crystal X-ray diffraction. The thiadiazoline ring is roughly planar, although it may be regarded as having a half-chair conformation. The cyclohexenyl ring has a half-chair conformation. The most interesting feature is the formation of a pseudo-ring formed by four molecules associated through N—H⋯O hydrogen bonds around a fourfold inversion axis, forming an R 4 4(28) motif.

(4aS,10aS)-7-Hydr-oxy-8-isopropyl-1,1,4a-trimethyl-1,2,3,4,4a,9,10,10a-octa-hydro-phenanthrene: a new diterpenoid compound.

The new title diterpenoid compound, C20H30O, is a natural product isolated from Tetraclinis articulata wood via chloroform extraction. The asymmetric unit contains four molecules with the same S,S configuration, deduced from the chemical synthesis. Indeed, an overlay analysis, calculated using structure-matching software, shows that the four molecules can be superimposed. The central ring has a half-chair conformation, whereas the saturated ring displays a chair conformation.

Hemisynthesis of New Triterpene Derivatives using Oxidation by CrO3 and NaIO4‐(RuCl3, 3H2O)

Abstract Oxidation of triterpenes resulting from E. resinifera, E. officinarum, and their derivatives, using chromic anhydride (CrO3) and the system NaIO4‐(RuCl3,3H2O), gives carbonyl triterpenic compounds with high chemioselectivity.

(3S)-Tosyl-24-methyl-elemo-lanosta-8,24(31)-diene-7,11-dione

To a solution of 11 (1g, 1.68mmol) in 20ml of acetone, was added (0.50g, 0.85mmol) of chromic anhydride2.[...]

(1S,3R,8R,10R)-2,2-Di­bromo-3,7,7,10-tetra­methyl­tri­cyclo­[6.4.0.01,3]dodecan-9-one

The title compound, C16H24Br2O was synthesized by three steps from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from essential oil of the Atlas cedar (Cedrus atlantica). The molecule is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The six-membered ring shows a chair conformation. One C atom in the seven-membered ring and two methyl groups attached to the ring are disordered over two sets of sites, with an occupancy ratio of 0.658 (7):0.342 (7).