Structure électronique de quelques dérivés nitrés insaturés (méthode L.C.A.O. améliorée)

The electronic structure of Nitro-,p- andm-dinitro-,s-trinitro-benzene, nitro-ethylene, mono-, and dinitro-butadien have been calculated by an improved LCAO method.     

NMR of some benzodiazepine drugs: Structure elucidation with lanthanide-induced shifts of N-1 substituted benzodiazepinones

Two 1,4-benzodiazepinones of psychopharmacological interest, pinazepam (2) and prazepam (3), were studied in solution by ¹³C and ¹H NMR. ¹H variable-temperature experiments showed that the seven-membered ring exists in a simple pseudo-boat form at room temperature, but the energy barrier is higher in 3 (ΔG_405°c = 82.8 kJ mol^?1) than in diazepam (1). Moreover, upon addition of LSR, the boat conformation is retained in the lanthanide ion-substrate complex, as with 1 in the solid state. Using a concentration-dependent shift technique and a computer-assisted LIS method, the conformations of the N-branched side-chain were investigated. Two preferred orientations were found for the propargyl group of 2, while three unequally populated conformations of the cyclopropyl moiety of 3 are distributed preferentially in the sterically unhindered space around the complex.     

Magallanesine: an isoindolobenzazocine alkaloid

$\text{Berberis darwinii}$ Hook.(Berberidaceae) has yielded magallanesine ($\text{1}$), the first known isoindolobetizazocine alkaloid.     

Amperometric bienzyme electrode for l-carnitine

An electrochemical sensor with two soluble enzymes allows assay of 0.1–10 mM, l- carnitine with an accuracy of 2%. The assay takes about 2 min. The first enzyme, carnitine dehydrogenase, catalyzes the oxidation of l-carnitine by NAD⁺. The NADH formed is oxidized by hexacyanoferrate(III) in a reaction catalyzed by diaphorase, and the hexacyanoferrate(II) produced is oxidized by electrolysis at 0.3 V. The sensor can be used for several days.     

La tablette babylonienne AO 17264 du musée du louvre et le problème des six frères

This tablet contains only one problem, that of dividing a Trapezium in six parts, equal two by two, and determined by the length of their sides. The solution is given in terms of nineteen integers. How was this solution found? Analysis of the text shows that the initial trichotomy of the trapezium was produced by an arbitary calculation, that the calculator probably tried, without success, to provide a minimal solution, and that pythagorean triplets were central. We thus have instructive evidence about the ambitions and limits of Babylonian mathematics.     

Thermodynamic behaviour of some glycol—water mixtures. Excess and partial volumes

Densities of water—glycol (mono- di-, tri- and tetraethyleneglycol) mixtures have been measured over the entire composition range at 298. 15 K. Mixtures involving monoethyleneglycol (MEG) have also been studied at different temperatures from 308.15 to 288.15 K. Deviations, V^E, from ideal volumes of mixing have been calculated: negative values are observed for all systems. They increase with the number of ether functions present in the organic molecule; a slight dependence of V^E towards temperature has been shown in the water—MEG mixtures. Partial molal volumes have also been calculated for both components of each system; they exhibit an extremum in the water-rich region.     

Revised structures for fumaritridine and fumaritrine: Two indenobenzazepine type alkaloids

Fumaritridine and fumaritrine are not spirobenzylisoquinolines. Rather, they are indenobenzazepines so that fumaritridine is represented by expression $\text{10}$ and fumaritrine by $\text{11}$. Treatment of dihydroparfumine ($\text{6}$) and dihydroparfumidine ($\text{7}$) uith trifluoroacetic anhydride folloued by quenching with methanol gives $\text{10}$ and $\text{11}$, respectively.