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Optically pure bicyclo[3.3.0]octane-2,6-dione is easily obtained with a yield of 4% for each enantiomer from 1,5-cyclooctadiene in 5 steps, by resolution of the intermediate diol with menthyloxyacetic acid. Its CD is 60% larger than twice the CD of a corresponding monoketone indicating interactions between non-conjugated chromophores.

Alkynes R-CCH were obtained in good yield through a one-pot procedure by a sequence of reactions starting from a Wittig-type condensation of the aldehydes RCHO with the ylide derived from dibromomethyltriphenylphosphonium bromide 5. The same reactions could also be used to prepare the intermediate dibromoalkenes RCHCBr2, and in certain cases, the bromoalkynes R-CCBr.

Iodoalkynes RCCI were obtained in good yield through a one-pot procedure by reaction of the aldehydes RCHO with diiodomethyltriphenylphosphorane first generated in situ from iodoform, triphenylphosphine and t -BuOK.

The design of the smallest spheroarenes (C(N) molecules based on trivalent polyhedral framework, a class which subsumes fullerenes) of any point-group symmetry is presented. The role of Curie's principle is discussed. Some molecules whose carbon backbone is a nonplanar graph are described.

A simplified procedure is described for assigning Cahn-Ingold-Prelog descriptors to stereocentres in spheroalkanes (the CnHn molecules, with n even, based on trivalent, polyhedral carbon frameworks, a class which subsumes the fulleranes). By extension, similar descriptors can be found for the atoms of fullerenes and related carbon-only molecules. Assignment maps are given for chiral fullerenes C28 C76, C78, C84 and C140, and for a number of spheroalkanes. Cases of breakdown of the simple procedure for triangle-rich spheroalkane molecular graphs are discussed.

Two charged aminoxyls, ammonium (1-oxyl-2,5,5-trimethylpyrrolidin-2-yl)methanesulfonate and ammonium 2-methyl-2-[(N-(4-tert-butylphenyl)oxyl]propanesulfonate, obtained by methods easily adaptable to the preparation of various other aminoxyls are totally soluble in water but are partially associated in other solvents.

A novel 2∶1 (permethylated-β-cyclodextrin)–fullerene conjugate has been synthesised; highly soluble in cold water with formation of aggregates, it displays a negative solubility coefficient and has a partition coefficient between octanol and water (Log P = 1.58) in the suitable range for biological studies.

Two β-cyclodextrin–C60 conjugates ( 3 and 4 ) with a flexible linker at the secondary face of cyclodextrin are synthesized by a single reaction of 2-(ω-azidoundecanyl)-2-O-heptakis (2,3,6-tri-O-methyl)-β-cyclodextrin ( 2 ) and C60, both of which display satisfactory water solubility. Structural analyses show that 3 is a closed [5,6] aziridinofullerene, whereas 4 is a bis-adduct derivative. Using rhodamine B (RhB) as a guest molecule, the inclusion complexation behavior of 3 was investigated in aqueous solution.

The classical chemical structure theory (CST) provides “localised” qualitative models for the structure and reactivity of organic molecules, while, in addition to quantitative methods, the modern molecular orbitals (MO) theory provides “delocalised” qualitative models. In particular, these two theories provide two different descriptions of the ethylenic double bond, bent bonds and σ/π orbitals, respectively. In the framework of CST, a graphical model of aromaticity and antiaromaticity, related to a classical model of Woodward–Hoffmann rules, is presented. By application of Linnett's double-quartet theory, a new representation for benzene is proposed. It can be easily visualised when a new split representation of Linnett-type formulae is used.

Pyrimidinyl nitronyl nitroxides where the bis-N-oxy fragment is included in a six-membered ring were prepared from diacetonamine by a sequence of reactions including a Grignard reaction, a Ritter reaction and oxidation of the intermediate pyrimidine; the properties of the 2-phenyl-substituted representative are fully described.

The new oxaziridine nitroxide, 2,2,4,4,6-pentamethyl-7-oxa-1,3-diaza-bicyclo[4.1.0]heptan-3-oxyl, has been obtained in 90% yield by oxidation of 2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydro-pyrimidine with MCPBA in ether. This nitroxide is stable in the solid state or in non-protic solvents. It was converted to the known 2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydro-pyrimidine-1-oxyl by successive reduction with LiAlH4 and oxidation with Ag2O, with a reproducible yield of 16% from the starting tetrahydropyrimidine.

β,β,β-Trichloroethoxycarbonyl, a useful amino protecting group, reacts selectively on the less hindered amino group of diamines; further oxidation of the hindered amino group and removal of the masking group leads to amino-nitroxides.

Oxidation des Hydroxylamins (I) mit Bleitetraacetat in Methylenchlorid liefert, wie sich ESR-spektroskopisch nachweisen last, das Aminoxyl-π-Radikal (II), dessen Zersetzung zu p-Nitrodiphenylamin (III) sowie zum N-Oxid des (N-p-Nitrophenyl)-p-benzochinonimins (IV) fuhrt.

International audience; ConspectusThe chemical study of materials from natural history and cultural heritage, which provide information for art history, archeology, or paleontology, presents a series of specific challenges. The complexity of these ancient and historical materials, which are chemically heterogeneous, the product of alteration processes, and inherently not reproducible, is a major obstacle to a thorough understanding of their making and long-term behavior (e.g., fossilization). These challenges required the development of methodologies and instruments coupling imaging and data processing approaches that are optimized for the specific properties of the materials. This Account discusses how these characteristics not only constrain their study but also open up specific innovative avenues for providing key historical information. Synchrotron methods have extensively been used since the late 1990s to study heritage objects, in particular for their potential to provide speciation information from excitation spectroscopies and to image complex heritage objects and samples in two and three dimensions at high resolution. We examine in practice how the identification of key intrinsic chemical specificities has offered fertile ground for the development of novel synchrotron approaches allowing a better stochastic description of the properties of ancient and historical materials. These developments encompass three main aspects: (1) The multiscale heterogeneity of these materials can provide an essential source of information in the development of probes targeting their multiple scales of homogeneity. (2) Chemical alteration can be described in many ways, e.g., by segmenting datasets in a semiquantitative way to jointly inform morphological and chemical transformation pathways. (3) The intrinsic individuality of chemical signatures in artifacts triggers the development of specific strategies, such as those focusing on weak signal detection. We propose a rereading of the advent of these new methodologies for analysis and characterization and examine how they have led to innovative strategies combining materials science, instrument development, history, and data science. In particular, we show that spectral imaging and the search for correlations in image datasets have provided a powerful way to address what archeologists have called the uncertainty and ambiguity of the material record. This approach has implications beyond synchrotron techniques and extends in particular to a series of rapidly developing approaches that couple spectral and spatial information, as in hyperspectral imaging and spatially resolved mass spectrometry. The preeminence of correlations holds promise for the future development of machine learning methods for processing data on historical objects. Beyond heritage, these developments are an original source of inspiration for the study of materials in many related fields, such as environmental, geochemical, or life sciences, which deal with systems whose alteration and heterogeneity cannot be neglected.