A. Auhmani

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.

6-Hydr­oxy-7-isopropyl-1,1,4a-trimethyl-2,3,4,4a,10,10a-hexa­hydro­phenanthren-9(1H)-one

The title compound, C20H28O2, commonly named Sugiol, is a natural oxygenated diterpene that we have isolated for the first time from a hexane extract of the fruits of Juniperus Oxycedrus L. Its X-ray crystal structure determination confirms an abietane skeleton which was predicted by spectroscopic analysis, mainly by 1H and 13C NMR. The cyclohexane ring adopts a flattened chair conformation, while the cyclohexene ring adopts an envelope conformation. The molecules are linked through O—H⋯O hydrogen bonds to form a zigzag chain extending parallel to the c axis.

Cyclopropanation reactions on α-cis-himachalene and a β-himachalene

The crystallographic structures of 2a,3a,7a,15a-tetrabromocarbene-himachalane, C17H24Br4, (3), 2a,3a,7a,15a-tetrachlorocarbene-himachalane, C17H24Cl4, (4), and 6a,7a-dichlorocarbene-himachal-2-ene, C16H24Cl2, (5), resulting from cyclopropanation reactions of the C═C double bonds of α-cis-himachalene and β-himachalene, are reported.

(1S,3S,8R,9S,10R)-9,10-Ep­oxy-3,7,7,10-tetra­methyl­tri­cyclo­[6.4.0.01,3]dodeca­ne

The title compound, C16H26O, was synthesized by treating (1S,3S,8R)-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodec-9-ene with metachloroperbenzoic acid. The molecule is built up from two fused six- and seven-membered rings. The six-membered ring has a half-chair conformation, whereas the seven-membered ring displays a boat conformation. In the crystal, there are no significant intermolecular interactions present.

(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,3S,8R,9S)-3,7,7,10-Tétraméthyl-9-[(1S,3S,8R,9S)-3,7,7-triméthyl-10-méthylène­tri­cyclo[6,4,0,01,3]dodéc-9-yl­oxy]­tri­cyclo[6,4,0,01,3]­dodéc-10-ène

The stereochemistry of the product resulting from the rearangement of (1S,3R,8R,9R,10R)-9,10-epoxy-3,7,7,10-tetramethyltricyclo[6,4,0,01,3]dodecane has been established by X-ray crystallography. The molecule, C32H50O, is composed of two distinct parts linked by a dioxo bond. In each part of the molecule, the conformation of the six-membered ring is imposed by the position of the double bond.

Electrochemical Studies of Monoterpenic Thiosemicarbazones as Corrosion Inhibitor for Steel in 1 M HCl

We have studied the inhibitory effect of some Monoterpenic Thiosemicarbazones on steel corrosion in 1 M HCl solution. The potentiodynamic polarization and electrochemical impedance spectroscopy were used. The Monoterpenic Thiosemicarbazones have inhibited significantly the dissolution of steel. The inhibition efficiency increased with increasing inhibitor concentration and also with the increase in temperature (293–323 K). Furthermore, the results obtained revealed that the adsorption of inhibitor on steel surface obeys Langmuir adsorption model and the thermodynamic parameters such as enthalpy and activation energy were determined. The scanning electron microscopy combined with dispersive X-ray spectroscopy examinations were used to see the shape of the surface morphology and to determine the elemental composition. Scanning electron microscope (SEM) images show that the surface damage decreases when the inhibitor is added. The quantum chemical calculations using density functional theory (DFT) were performed in order to provide some insights into the electronic density distribution as well as the nature of inhibitor-steel interaction.

(4bS,8aS)-1-Isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octa-hydro-phenan-thren-2-yl benzoate.

The title compound, C27H34O2, was hemisynthesized through direct benzoylation of the naturally occurring meroterpene totarol. The central fused six-membered ring has a half-chair conformation, whereas the terminal six-membered ring displays a chair conformation. The dihedral angle between the fused benzene ring and the benzoyl benzene ring is 73.05 (14)°. The S,S chirality of the molecule is consistent with the synthetic pathway, and confirmed by the refinement of the Flack parameter.

Absolute configuration of (1S,3R,8R)-10-bromo­methyl-2,2-di­chloro-3,7,7-tri­methyl­tri­cyclo­[6.4.0.01,3]dodec-9-ene

The absolute configuration of the title compound, C16H23BrCl2, has been deduced from the chemical pathway and fully confirmed by refinement of the Flack and Hooft parameters. The six-membered ring adopts a half-chair conformation, whereas the seven-membered ring is a twisted chair. The molecular packing within the crystal is stabilized only by van der Waals interactions.

1,4a-Dimethyl-6-methyl­ene-5-(5,5,6,6-tetra­cyano-2-methyl­cyclo­hex-2-enylmeth­yl)deca­hydro­naphthalene-1-carboxylic acid: a trans-communic acid derivative

In the search for cancer chemopreventive agents, we have studied the Diels–Alder reaction of trans-communic acid with tetracyanoethylene in the presence of SiO2 as catalyst. The title cycloadduct, C26H30N4O2, was obtained in 75% yield. The molecules are arranged in pairs through O—H⋯O hydrogen bonds, forming an R 2 2(8) ring motif. Both the fused cyclohexyl rings adopt a chair conformation, whereas the nonfused ring adopts a half-chair conformation.