A New Preparation of 1,3,3‐Trimethylbicyclo[2.2.2]octan‐2,6‐dione,a Never Isolated Intermediate in a Total Synthesis of (+)‐Norpatchoulenol. Formal Total Synthesis of (±)‐Iso‐Norpatchoulenol

A new preparation and the isolation and spectroscopic characterization of 1,3,3‐trimethylbicyclo[2.2.2]octan‐2,6‐dione ( 3 ), a so far elusive key intermediate in the Liu–Ralitsch total synthesis of (+)‐norpatchoulenol ((+)‐ 1a ), is described. The preparation of 3 constitutes also a formal total synthesis of (±)‐iso‐norpatchoulenol ((±)‐ 1b ), since 3 is correlated to an intermediate in the Monti and co‐workers synthesis of (±)‐ 1b .     

Diastereoselective total synthesis of (+)-13-stemarene by fourth generation methods: a formal total synthesis of (+)-18-deoxystemarin

The problem of constructing diastereoselectively the C/D ring system of stemarane diterpenes from a bicyclo[2.2.2]octane intermediate was solved resulting in very simple synthesis of (+)-13-stemarene 1. The obtaining of the latter represents also a formal synthesis of (+)-18-deoxystemarin 2. In the key step, the epimeric mixture 10, dissolved in toluene, was converted by the action of TsOH into (+)-stemar-13-en-15-one 28.     

On the Diastereoselectivity of the Aqueous-Acid-Catalyzed Intramolecular Aldol Condensation of 3-Oxocyclohexaneacetaldehydes

The factors responsible for the diastereoselective formation of the 6-endo-hydroxybicyclo[2.2.2]octan-2-one by acid-catalyzed intramolecular aldol reaction of 3-oxocyclohexaneacetaldehydes have been investigated. This study, carried out on (1SR,4RS,6RS)-6-hydroxybicyclo[2.2.2]octan-2-one 1a , (1SR,4RS,6SR)-6-hydroxybicyclo[2.2.2]octan-2-one 1b , and 3,3-(ethylenedioxy)cyclohexaneacetaldehyde 2a , allowed to demonstrate the absence of intramolecular H-bonding in 1a as a stabilizing factor, and to ascertain the presence of unfavorable steric interactions in 1b .     

Search for high energy γ-rays emission in28Si,32S+64Ni dissipative reactions at about 5 MeV/amu incident energy

Photons emitted in the²⁸ Si+⁶⁴ Ni and³² S+⁶⁴ Ni reactions at 143 MeV and 156 MeV incident energy respectively, have been detected in coincidence with the ejected charged fragments. An array of 48 BaF₂ -rays detector and 6 solid state silicon detector telescopes have been used. Photon energy spectra measured in the energy range from 2 to 20 MeV in coincidence with ejectiles coming from deep inelastic reactions, are consistent with statistical emission from the reaction products.Thanks are due to Dr.T.Noorman for the suggestions in the statistical calculations and to Mr.C.Marchetta for the preparation of high quality targets.     

Stemodane Diterpenes and Diterpenoids: Isolation,Structure Elucidation,Biogenesis, Biosynthesis,Biological Activity,Biotransformations, Metabolites and Derivatives Biological Activity,Rearrangements

The scientific activity carried out over forty-five years on stemodane diterpenes and diterpenoids structure elucidation, biogenesis, biosynthesis, biological activity and biotransformations was reviewed.     

Strong enhancement of extremely energetic proton production in central heavy ion collisions at intermediate energy

The energetic proton emission has been investigated as a function of the reaction centrality for the system (58)Ni + (58)Ni at 30A MeV. Extremely energetic protons (E(NN)(p) > or = 130 MeV) were measured and their multiplicity is found to increase almost quadratically with the number of participant nucleons, thus indicating the onset of a mechanism beyond one- and two-body dynamics.     

Towards a better understanding of deep subthreshold photofission of238U

Deep subthreshold photofission data of²³⁸U are analysed. Spectroscopic properties of highly deformed states from experiments in the literature are introduced into a model calculation based on the doorway state formalism which is extended to fission at energies as low as the isomeric level. It is shown that starting from the results of a detailed analysis of the photofission measurements near the top of the fission barrier it is possible to describe the process in the energy range covered by the intermediate well in the double-humped deformation potential. In particular, the so-called “shelf effect” in the low energy photofission is reproduced in terms of delayed isomeric fission through a few undamped vibrational states localised in the pairing gap region above the isomer.     

Spectroscopic characterization of 6-hydroxy and 1-methyl-6-hydroxybicyclo[2.2.2]octan-2-one ethylene acetals and ethylene dithioacetals

6-endo- and 6-exo-Hydroxybicyclo[2.2.2]octan-2-one and 1-methyl-6-endo- and 6-exo-hydroxybicyclo[2.2.2]octan-2-one ethylene acetals and ethylene dithioacetals 1-4 have been characterized by 1D and 2D NMR methods.