Chemoenzymatic synthesis of α-halogeno-3-octanol and 4- or 5-nonanols. Application to the preparation of chiral epoxides

A study of the microbiological reduction of different α-halogenoketones (4-chloro-3-octanone, 4-chloro-5-nonanone, 5-bromo-4-nonanone and 5-chloro-4-nonanone) with several strains of microorganism showed great difficulty in reducing ketone functions located in the middle of carbon chains. However, by choosing the appropriate microorganism, several enantiomerically pure diastereoisomers of the corresponding halohydrins have been obtained and were transformed into chiral epoxides.     

Étude des restes pour les suites de Van Der Corput généralisées

We get the asymptotic behaviour of the remainder function with respect to the Van Der Corput generalized sequences construted in a previous paper (in Bulletin de la S.M.F, n^o 109, 1981). As a consequence, we obtain the intervals [0, a] for which the remainder is bounded. Moreover, we give an explicit formula for the remainder with respect to the Van Der Corput sequence in the r-adic system.     

Clinical investigations of catecholaminergic systems using liquid chromatography with electrochemical detection

Catecholamine levels in body fluids are reliable biochemical markers of several types of tumors, cardiovascular diseases and hereditary and metabolic disorders. Reversed-phase liquid chromatography with electrochemical detection (RPLC-EC) is now the method of choice for catecholamine analysis.     

Tetraazamacrocycles lipophiles : synthese et application a l'extraction de Cu (II), Cd (II) et Pb (II)

The synthesis of three lipophilic n-dodecyl tetraazacycloalkanes is described. Extraction of Cu(II), Cd(II) and Pb(II) is related.     

Unexpected formation of rearrangement and fragmentation products during the thermal activation of pyrazolino diazepines

Ionic and radical mechanistic steps are postulated in order to explain the formation of the rearrangement-, the isomerization- and the fragmentation-products isolated during the thermal treatment of pyrazolo-diazepines.     

Optimization of a binary transcoding single filter used for character recognition

We propose a new type of optical filter for character recognition. We intend to show that a unique optimized filter is suitable for binary transcoding of an alphabetical set. The unique filtering consists of a multiplexing from a superposition of holographic filters. Synthesis can be implemented either by analog holography or by numerical holography. A verification obtained from a limited alphabet is presented.     

Action du N-bromosuccinimide sur les dioxolannes en série bicyclo [2.2.1 ]heptanique. Limitation des transpositions de wagner-meerwein

Vicinal benzoyloxy-trans-bicyclo [2.2.1] heptanic bromhydrins, otherwise difficult to obtain are formed from N-bromosuccinimide and norbornanes bearing a 2-aryl-1,3 dioxolane skeleton. The greater stability of the intermediate dioxolenium ion reduces the tendency towards both Wagner-Meerwein rearrangement and neighbouring group participation by chlorine, processes usually observed when a less stable intermediate is involved. Nevertheless, methoxycarbonyl neighbouring group participation and Wagner Meerwein rearrangment occur in methoxycarbonylbicyclo [2.2.1]heptane and in a bornanic compound respectively.