A Concise Synthesis of rac‐Ambrox® via the Palladium(0)‐Catalyzed Carboalkoxylation of an Allylic Ammonium Salt,as Compared to a Formaldehyde Hetero Diels–Alder Approach

Acidic cyclization of either the diethylallylamines 29b or 30 , followed by a 1.5 mol‐% Pd‐catalyzed carbomethoxylation of quaternized 31b , leads to the methyl ester 36a . This latter could also be obtained in optically pure form by carbomethoxylation of the corresponding (+)‐acetate. Final reduction‐cyclization may be conducted as earlier described, towards the desired odoriferous rac‐Ambrox® 38a , or its pure (?)‐enantiomer. Generation of a π‐allyl Pd complex from an allylic ammonium salt, followed by carboalkoxylation is novel. In only five chemical steps starting from farnesene 2 , the present work constitutes the most concise total synthesis of rac‐Ambrox® 38a to date.     

Influence and Enhancement of Damping Properties of Wire Rope Isolators for Naval Applications

Wire Rope Isolators (WRI) are well known and used for the protection of sensitive equipment against non-contact underwater explosions (UNDEX) on board Naval Ships, amongst others, which are extremely destructive and can comple`tely impair the ship’s combat capability.
Traditional WRI exhibit a number of definite advantages, such as large deflection capability, modularity and insensitivity to aggressive environment when proper materials are used. However, their inherent nonlinearity does not always provide the best solution in terms of shock attenuation. (Stiffening tension characteristics)
Fortunately, there are ways to overcome this problem, namely increasing their damping and/ or changing their aspect ratio. It is the purpose of this presentation to show how to overcome this problem and through analysis, by use of validated models of the shock testing machines. The existing technology will be briefly presented and HDWRI (high damping wire rope isolators) vs. conventional WRI responses will be compared on the US Navy shock testing machines of MIL-S-901D.
The US Navy standard MIL-S-901 defines a physical shock testing machine to impact the target before its approval. Different testing machines are used (LWSM, MWSM, FSP, and new DSSM) depending on the weight and size of the target, and on the deck frequency simulated.
The Socitec Group has developed a full model of the various shock testing machines using its in-house developed SYMOS software package. Currently, the Group is in the process of completing a model for the DSSM.     

Advantages and Drawbacks of Quantum Mechanical Static and Dynamic Approaches to Modelling Infrared Spectra

利用超简谐振动近似的有效二阶微扰法(VPT2)和变异微扰法(VCI-P)两种静态方法,以及在300和600K下的密度泛函分子动态轨线振动分析方法进行量子力学的振动计算. 比较了这四种方法对于基频跃迁频率和对应的中红外光谱在相同的B3LYP/6-31+G(d,p)基组描述电子结构前提下所得到的计算结果. 总结了对于半刚性和柔性分子的主要结果,并且对这些计算方法的优缺点进行了比较.     

Photo‐Rheometry/NIR Spectrometry: An in situ Technique for Monitoring Conversion and Viscoelastic Properties during Photopolymerization

Summary: A suitable rheometer for simultaneous dynamic mechanical analysis (DMA) and NIR (Near Infra‐Red) in situ analysis during UV curing was developed. The conversion and viscoelastic properties of a dimethacrylate/styrene‐based system were investigated. The results were plotted against both irradiation time and total average conversion. For the same conversion, a lower intensity delays the reaction but does not affect the viscoelastic properties.

A device for simultaneous photo‐rheology and NIR spectroscopy experiments.     

Chemical Variability and In Vitro Anti-Inflammatory Activity of Leaf Essential Oil from Ivorian Isolona dewevrei (De Wild. & T. Durand) Engl. & Diels

The chemical variability and the in vitro anti-inflammatory activity of the leaf essential oil from Ivorian Isolona dewevrei were investigated for the first time. Forty-seven oil samples were analyzed using a combination of CC, GC(RI), GC-MS and ¹³C-NMR, thus leading to the identification of 113 constituents (90.8–98.9%). As the main components varied drastically from sample to sample, the 47 oil compositions were submitted to hierarchical cluster and principal components analyses. Three distinct groups, each divided into two subgroups, were evidenced. Subgroup I−A was dominated by (Z)-β-ocimene, β-eudesmol, germacrene D and (E)-β-ocimene, while (10βH)-1β,8β-oxido-cadina-4-ene, santalenone, trans-α-bergamotene and trans-β-bergamotene were the main compounds of Subgroup I−B. The prevalent constituents of Subgroup II−A were germacrene B, (E)-β-caryophyllene, (5αH,10βMe)-6,12-oxido-elema-1,3,6,11(12)-tetraene and γ-elemene. Subgroup II−B displayed germacrene B, germacrene D and (Z)-β-ocimene as the majority compounds. Germacrene D was the most abundant constituent of Group III, followed in Subgroup III−A by (E)-β-caryophyllene, (10βH)-1β,8β-oxido-cadina-4-ene, germacrene D-8-one, and then in Subgroup III−B by (Z)-β-ocimene and (E)-β-ocimene. The observed qualitative and quantitative chemical variability was probably due to combined factors, mostly phenology and season, then harvest site to a lesser extent. The lipoxygenase inhibition by a leaf oil sample was also evaluated. The oil IC₅₀ (0.020 ± 0.005 mg/mL) was slightly higher than the non-competitive lipoxygenase inhibitor NDGA IC₅₀ (0.013 ± 0.003 mg/mL), suggesting a significant in vitro anti-inflammatory potential.     

Polymer and organic molecules ordered via epitaxy: geometrical and molecular interactions

Control of structural order at the molecular level for both conventional linear polymers and conjugated polymers with valuable opto‐electronic properties has major consequence on the macroscopic properties of these polymers. Though the traditional means of orientation of polymer was mechanical deformation, presently extensive works are concerned with a more controlled way of orientation: epitaxial crystallisation. Most of the first documented examples of epitaxial growth of conventional polymers on single crystals followed the well‐established geometrical rules of best matching. However, recent examples show off more subtle rules of selection. Analogous cases, following or breaking the matching rules, have been observed for diacetylenes ordered via epipolymerisation on single crystals. Hereafter, representative examples of the structural matching rules are depicted first, and then recent examples, which depart from the simple geometrical fitting, are described. The analysis of the former leads to define the subtle matching rules applying for polymers linked to their conformational adaptability. The analysis of the latter gives the opportunity to discuss the relative influence of geometrical and molecular interactions between the deposit and the substrate.