Modelling the signal delivered by a population of first-order neurons in a moth olfactory system

A statistical model of the population of first-order olfactory receptor neurons (ORNs) is proposed and analysed. It describes the relationship between stimulus intensity (odour concentration) and coding variables such as rate and latency of the population of several thousand sex-pheromone sensitive ORNs in male moths. Although these neurons likely express the same olfactory receptor, they exhibit, at any concentration, a relatively large heterogeneity of responses in both peak firing frequency and latency of the first action potential fired after stimulus onset. The stochastic model is defined by a multivariate distribution of six model parameters that describe the dependence of the peak firing rate and the latency on the stimulus dose. These six parameters and their mutual linear correlations were estimated from experiments in single ORNs and included in the multidimensional model distribution. The model is utilized to reconstruct the peak firing rate and latency of the message sent to the brain by the whole ORN population at different stimulus intensities and to establish their main qualitative and quantitative properties. Finally, these properties are shown to be in agreement with those found previously in a vertebrate ORN population

Synthesis and applications of chiral polyether macrocycles

A single-step methodology was previously developed to transform unsaturated polyether macrocycles into chiral crown ethers (dr > 98:2). This tandem amidation-olefin transposition process involving aromatic amines under basic conditions was further explored and used for different applications during this PhD. First, development of a new methodology with aliphatic amines, by preformation of the bis-amides and subsequent olefin transpositions, afforded new chiral crown ethers. Then, cryptands were obtained thanks to a late-stage functionalization of some chiral crown ethers. These new receptors exhibited a heteroditopic character toward salts made of sodium and linear anions in particular, which was demonstrated by 1H NMR spectroscopy and solid state structure analysis. Finally, when chiral crown ethers are synthesized with certain fluorescent aromatic amides (pyrene, perylene, NMI or fluorene derivatives), a strong excimer fluorescence was measured due to the spatial proximity of the fluorescent arene moieties. The study of the chiroptical properties of these enantiopure macrocycles proved to be a rare examples of allied +/- ECD and on/off CPL reversible switches

From reactive carbenes to chiral polyether macrocycles in two steps – synthesis and applications made easy?

Chiral polyether macrocycles are versatile molecules. For their preparation, original two-step procedures were recently developed and present the advantages of high concentration conditions and simple starting reagents (stable diazo reagents, small cyclic ethers, aliphatic or aromatic amines). Enantiopure materials are readily afforded by CSP-HPLC on a semi-preparative scale. Flexibility and adaptability in the macrocyclic design are provided by a large selection of amines to choose from while the ring size and chemical nature are controlled by the choice of 5 to 7-membered cyclic ether precursors. Such macrocycles have already been used as asymmetric catalysts, mono and ditopic receptors, fluorescent sensors and probes, and chiroptical reversible switches

FUNCTIONALIZED POLYETHER MACROCYCLIC COMPOUNDS AND USE THEREOF AS LUMINESCENT MARKERS

The invention relates to chiral enantioenriched functionalized polyether macrocyclic compounds displaying bright circularly polarized light emission and use thereof as luminescent markers

Stereoselective deconjugation of macrocyclic α,β-unsaturated esters by sequential amidation and olefin transposition: application to enantioselective phase transfer catalysis

The stereoselective synthesis of chiral macrocycles bearing two aliphatic amide functional groups is reported. After the amidation mediated by TBD, a guanidine derivative, the olefin transposition step is performed with a slight excess of t-BuOK. The products are afforded in moderate to good combined yields (up to 59%) and with an excellent syn diastereoselectivity (dr > 49 : 1). Introducing enantiopure α-branched substituents was possible and it resulted in mixtures of diastereomers, which could be tested as phase-transfer catalysts using the formation of a phenylalanine analog as a test reaction (up to 43% ee). A clear matched–mismatched situation was observed in the two diastereomeric series

Kinetics of Rh(II)-Catalyzed α-Diazo-β-ketoester Decomposition and Application to the [3+6+3+6] Synthesis of Macrocycles on Large Scale and Low Catalyst Loadings

In the context of [3+6+3+6] macrocyclization reactions, precise kinetics of α-diazo-β-ketoester decomposition were measured by in situ infrared (IR) monitoring. Dirhodium complexes of Ikegami–Hashimoto type—and perchlorinated phthalimido derivatives in particular—performed better than classical achiral complexes. Clear correlations were found between speciation among dirhodium species and catalytic activity. With these results, novel cyclohexyl-derived catalysts were developed, affording good yields of macrocycles (up to 78%), at low catalyst loadings (from 0.01 mol % to 0.001 mol %) and on a large scale (from 1 g to 20 g)

Efficient Synthesis of Ditopic Polyamide Receptors for Cooperative Ion Pair Recognition in Solution and Solid States

Following a late-stage functionalization strategy, a series of heteroditopic cryptand receptors were prepared in three steps only from 1,4-dioxane. As evidenced by 1H NMR spectroscopic and solid state analyses, these polyamide–crown ether conjugates present general ion pair binding capacity towards salts of monovalent cations and linear triatomic anions

Dataset of Organic & Biomolecular Chemistry_Aliphatic amide macrocycles

AbstractNMR, IR, MS and X-ray files for the article entitled: Stereoselective deconjugation of macrocyclic α,β-unsaturated esters by sequential amidation and olefin transposition: application to enantioselective phase-transfer catalysi

One-Step Synthesis of Diaza Macrocycles by Rh(II)-Catalyzed [3 + 6 + 3 + 6] Condensations of Morpholines and α-Diazo-β-ketoesters

Selective formation of oxonium ylides from morpholines and α-diazo-β-ketoesters was achieved. This was applied to the high-concentration (0.5 M) dirhodium-catalyzed (0.1 mol %) [3 + 6 + 3 + 6] synthesis of 18-membered ring diaza macrocycles (46%–72%). Late-stage functionalization of these derivatives is demonstrated. Mechanistic evidence for a novel (undesired) diazo decomposition pathway is also reported