Sun-reactive Skin Type in 4912 French adults participating in the SU.VI.MAX study

Phototype classifications were initially developed in an attempt to predict the skin reactions of patients to phototherapy and are now widely used to advise individuals with regard to sun protection. A transversal study was conducted on the SU.VI.MAX cohort to estimate the frequency of sun-reactive skin features in a large, general adult population-based sample, and to describe the associations between these features. The data were collected 3 years after the beginning of the SU.VI.MAX nutritional intervention study on 4912 volunteers (2868 women aged 35-60 years and 2044 men aged 45-60 years). A multiple correspondence analysis was performed to study the associations between the features. The results showed that these features correspond to a one-dimensional phenomenon, which allowed us to establish a score to summarize skin sensitivity to sun exposure. Furthermore, we found a link between gender and phototype using the Césarini classification (phototype > or = IV: 37% of women, 47% of men). The analysis of the relationship with sun-reactive skin features and the score revealed the same trend. Phenotypic evaluation appears to be a good estimator of skin sensitivity to sun exposure for clinical screening or for use in research, and is easy to collect at a lower cost. Moreover, the sun sensitivity difference between gender should be considered in education about photoprotection.     

Towards schizozygine: synthesis of 15α-hydroxystrempeliopine

15α-Hydroxystrempeliopine (6), a model hexacyclic base for our planned total synthesis of schizozygine (2), has been synthesized using a Zn-mediated reductive rearrangement of indolenine 14 as the key step. The structure and relative stereochemistry of 6 were assigned by a combination of COSY, NOESY, HSQC and HMBC correlations.     

Why Does Pivalaldehyde (Trimethylacetaldehyde) Unexpectedly Seem More Basic Than 1‐Adamantanecarbaldehyde in the Gas Phase? FT‐ICR and High‐Level Ab Initio Studies

Fourier transform ion cyclotron resonance spectroscopy (FT ICR) techniques, including collision-induced dissociation (CID) methodology, were applied to the study of the gas-phase protonation of pivalaldehyde (1) and 1-adamantanecarbaldehyde (2). A new synthetic method for 2 was developed. The experiments, together with a thorough computational study involving ab initio and density functional theory (DFT) calculations of high level, conclusively show that upon monoprotonation in the gas phase, compound 1 yields monoprotonated methyl isopropyl ketone 3. The mechanism of this gas-phase acid-catalyzed isomerization is different from that reported by Olah and Suryah Prakash for the reaction in solution. In the latter case, isomerization takes place through the diprotonation of 1.     

On the mechanism of phthalimidine formation via o-phthalaldehyde monoimines. New [1,5]-H sigmatropic rearrangements in molecules with the 5-aza-2,4-pentadienal skeleton

[reactions: see text] Condensation reaction of o-phthalaldehyde with primary amines is a classical method for the synthesis of phthalimidines. Although the intermediacy of the corresponding monoimines has been occasionally proposed, the mechanism of their transformation into phthalimidines remains to be elucidated. We present here theoretical evidence supporting a three-step mechanistic pathway for that transformation involving the [1,5]-H sigmatropic rearrangement of the aldehydic proton leading to an intermediate (aminovinyl)ketene as the key step. Other alternative routes have been calculated to be energetically less favorable. Similar transformations of related imino aldehydes enclosing a 5-aza-2,4-pentadienal skeleton via [1,5]-H shifts are also studied.     

The Unusual Transformation of an Aromatic 1<Emphasis Type="Italic">H</Emphasis>-Imidazole into a Non-Aromatic 2<Emphasis Type="Italic">H</Emphasis>-Imidazole

2H-Imidazole derivative 5 has been synthesized and characterized by the X-ray diffraction (XRD) method. The compound crystallizes in the monoclinic space group Cc with cell parameters a = 19.398(1), b = 8.890(1), c = 10.247(1), β = 110.76(1), Z = 4. The molecules are inter-linked through C–H⋅sO and C–H⋅sπ interactions forming infinite chains.     

Electrochemistry of copper complexes with macrocyclic polyamines containing pyrazole units

The voltammetric behaviour of bi- and mono-nuclear complexes formed in solution by Cu(2+) with three polyazacyclophanes containing pyrazole units in aqueous solution is described. Cyclic and square wave voltammetric responses at glassy carbon electrodes indicate that the reduction of copper-macrocycle complexes in solution takes place in two successive one-electron per Cu transfer processes coupled with preorganization and protonation reactions that mimic the behaviour of superoxide dismutase. The electrochemistry of ternary Cu(2+)-receptor-dopamine complexes exhibits significant differences with respect to the protection of the neurotransmitter from post-electron transfer cyclization reactions.     

Synthesis and 1H NMR studies of paramagnetic nickel(II) complexes containing bis(pyrazolyl)methane ligands with dendritic substituents

The substituted bis(pyrazolyl)methane ligands RCH(3,5-Me2pz)2(R=SiMe3, CH2Ph, G1, G2, and G3; Gn=Fréchet-type dendritic wedges of generation n) have been prepared starting from H2C(3,5-Me2pz)2. Reaction of these didentate ligands with [NiBr2(DME)] is a straightforward procedure that allows the synthesis of the nickel(II) complexes [NiBr2{RCH(3,5-Me2pz)2}]. The molecular structure of compound (R=CH2Ph) has been determined by X-ray diffraction studies. The nickel centre coordinates two bromine and two nitrogen atoms in a tetrahedral environment, and the metallacycle Ni(NN)2C adopts a boat conformation with the benzyl group in an axial position. 1H NMR studies have been carried out to characterize these paramagnetic nickel compounds in solution. Valuable information about the disposition of the ligands and dendritic wedges in solution has been obtained thanks to the influence of the paramagnetic centre on the proton resonances.     

Very efficient, reusable copper catalyst for carbene transfer reactions under biphasic conditions using ionic liquids

[reaction: see text] The complex {[HC(3,5-Me(2)pz)(3)]Cu(NCMe)}BF(4) catalyzes the transfer of the :CHCO(2)Et unit from ethyl diazoacetate to several saturated and unsaturated substrates with very high yields and under biphasic conditions using the ionic liquid [bmim][PF(6)] and hexane as the reaction medium. The catalyst has been tested for several cycles of recovery and reuse without any loss of activity.     

Electrocatalytical properties of polymethylferrocenyl dendrimers and their applications in biosensing

The electrochemical characterization of polymethylferrocenyl dendrimers deposited onto a platinum electrode and their applications as hydrogen peroxide and glucose sensor are described. The redox dendrimers consist of flexible poly(propileneimine) dendrimer cores functionalised with octamethylferrocenyl units. Amperometric biosensors for glucose were prepared by immobilization of glucose oxidase onto these modified electrodes. The influence of the dendrimer generation and the thickness of the dendrimer layer, the effect of the substrate concentration, and the interferences and reproducibility on the response of the sensors were investigated.