Ozonolyse d'olefines perfluorees

We have obtained unusually stable secondaxy ozonides ($\text{2a-c}$) by heating neat perfluoroalkenes ($\text{1a-c}$) with ozone.     

Nouveaux trioxophosphetanes generateurs d'oxygene singulet a basse temperature

We have prepared phosphite ozonides $\text{1b}$–$\text{3b}$ which are efficient and clean singlet oxygene generators at low temperature.     

Constituents of local plants

Summary A thin-layer Chromatographic procedure was developed for the detection and determination of steroidal alkaloids in plant tissue. A set of conditions is described for the differentiation between the intimately related aglycones of various types. The determination of the natural glycosides depends essentially on the photometric measurement of their Chromatographic spots with reference to calibration curves.

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Bestandteile einheimischer PflanzenXV. Dünnschicht-chromatographischer Nachweis und Bestimmung von Steroidalkaloidglykosiden und -aglykonen in Pflanzengewebe

Zusammenfassung Verschiedene dünnschicht-chromatographische Systeme werden für den Nachweis und Trennung der Glykoside und Aglykone beschrieben. Die quantitative Bestimmung erfolgt durch direkte Photometrie der Flecken.

     

The Behavior of 3,3-Diphenylindan-1,2-dione Towards Phosphonium Ylides

Summary. The reaction of alkoxycarbonyl- and cyanomethylene(triphenyl)phosphoranes with 3,3-diphenylindan-1,2-dione in dry benzene at room temperature for about 5 h led to the formation of a mixture of (E)- and (Z)-diastereomers. On the other hand, treatment of the dione with acetylmethylene(triphenyl)phosphorane afforded a mixture of (E)-3,3-diphenyl-1-(2-oxo-2-methylethylidene)indan-2-one and unexpected product (E)-3-(3,3-diphenyl-2-oxoindan-1-ylidene)-4-(triphenyl-λ⁵-phosphanylidene)hexane-2,5-dione, whereas with benzoylmethylene(triphenyl)phosphorane gave a mixture of (E)-3,3-diphenyl-1-(2-oxo-2-phenylethylidene)indan-2-one, [(2R ^*,3S ^*)-3-benzoyl-8,8-diphenyl-3,8-dihydro-2H-indeno{2,1-b}furan-2-yl]phenylmethanone and 1,4-diphenyl-2-(3,3-diphenyl-2-hydroxy-3H-inden-1-yl)but-2-ene-1,4-dione. The reaction mechanisms are considered and structural assignments of the new compounds are based on spectroscopic evidence. The molecular structures of the two diastereomers and the unexpected product were elucidated by X-ray crystallography.     

An exact algorithm for the petrol station replenishment problem

In the petrol station replenishment problem (PSRP), the aim is to deliver petroleum products to petrol stations by means of an unlimited heterogeneous fleet of compartmented tank trucks. The problem consists of jointly determining quantities to deliver within a given interval, of allocating products to tank truck compartments and of designing delivery routes to stations. This article describes an exact algorithm which decomposes the PSRP into a truck loading problem and a routing problem. An algorithm which makes use of assignment, optimality tests and possibly standard ILP algorithm is proposed to solve the loading problem. The routing problem is handled using two different strategies, based either on a matching approach or on a column generation scheme. This algorithm was extensively tested on randomly generated data and on a real-life case arising in Eastern Quebec.     

Solving a vehicle-routing problem arising in soft-drink distribution

The problem studied in this article arises from the distribution of soft drinks and collection of recyclable containers in a Quebec-based company. It can be modelled as a variant of the vehicle routing problem with a heterogeneous vehicle fleet, time windows, capacity and volume constraints, and an objective function combining routing costs and the revenue resulting from the sale of recyclable material. Three construction heuristics and an improvement procedure are developed for the problem. Comparative tests are performed on a real-life instance and on 10 randomly generated instances.     

A Nucleophilic Addition of Acetone Enolate to ( E)-Alkyloxindolylideneacetates

The reaction of (E)-(2-oxo-1,2-dihydroindol-3-ylidene)acetic acid esters with dry acetone at 70°C in presence of aluminum oxide as a catalyst led to the formation of an addition product as a mixture of two isomers. When the same reaction was carried out in presence of morpholine as a base, the unexpected spiro-product was obtained beside the two isomers. Methylation of the latter with methyl iodide in acetone in presence of anhydrous potassium carbonate yielded the corresponding methylated products, whereas methylation of the starting material by the same procedure gave an N-methylated product and the unexpected dispiro-compound. The reaction mechanisms are considered and the structural assignments of the new compounds are based on the chemical and spectroscopic evidences. The structure of the dispiro-product was derived by X-ray analysis.     

KINETICS,MEDIUM, AND DEUTERIUM ISOTOPE EFFECTS IN THE ALKALINE DECOMPOSITION OF QUATERNARY PHOSPHONIUM SALTS III1 Tetraphenylphosphonium Chloride in Dimethylsulphoxide-Water Mixtures

Abstract

The reaction between tetraphenylphosphonium chloride and hydroxide or deuteroxide anions was studied kinetically in a series of dimethylsulphoxide-water mixtures at several temperatures. The rate is first-order in the phosphonium cation and second-order in the hydroxide or deuteroxide anions. The reaction shows a dramatic increase in rate, up to about 10¹⁰ times, as the DMSO content is increased. The rate enhancement is attributed to a considerable drop in activation energy affected not only through an increased desolvation of reactant anions, but also through an increase in solvation of the transition state, brought about by gradual addition of DMSO. The kinetic solvent deuterium isotope effect in 60% DMSO-40% D₂O is strongly dependent on temperature. The rate constant in the latter solvent mixture is represented by k ⁱ = 11.9 e ^?12700/RT l ² mole^?2 sec^?1 as compared to k ⁱ = 19.0 e ^?22500/RT l ² mole^?2 sec^?1 in the corresponding 60% DMSO-H₂O mixture. The thermodynamic parameters of activation show strong dependence on solvent composition and are related to structural changes and solvation power of the reaction medium.     

A tabu search heuristic for the split delivery vehicle routing problem with production and demand calendars

The purpose of this article is to propose a tabu search heuristic for the split delivery Vehicle Routing Problem with Production and Demand Calendars (VRPPDC). This new problem consists of determining which customers will be served by a common carrier, as well as the delivery routes for those served by the private fleet, in order to minimize the overall transportation and inventory costs. We first model this problem and then propose a simple decomposition procedure that can be used to provide a starting solution. Next, we introduce a new tabu search heuristic and we describe two new neighbor reduction strategies. Finally, we present the results of our extensive computational tests. According to these tests, our reduction strategies are efficient not only at reducing computing time but also at improving the overall solution quality.     

Constituents of local plants

Summary The sterol constituents of the unsaponifiable fractions derived from the fats of Cucurbita pepo and Sinapis arvensis seeds and that of Clerodendron inerm leaves were seemingly uniform by the conventional thin-layer chromatographic methods. The mass spectra of these sterols, however, indicated that they were mixtures of several components. A study of the fragmentation behaviour was useful in indicating the number of component sterols in a given mixture and in giving information about their probable structures. The examples given illustrate the utility of mass spectrometry in the analysis of sterol mixtures.

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Zusammenfassung Im Rahmen einer Untersuchungsreihe über Pflanzenbestandteile wurden die Sterine der Samen von Cucurbita pepo und Sinapis arvensis sowie der BlÄtter von Clerodendron inerm analysiert. Bei der üblichen Dünnschichtchromatographie erwiesen sich diese Sterine scheinbar als einheitlich, wogegen die Massenspektrometrie zeigte, da\ es sich um Mischungen mit mehreren Bestandteilen handelt. Aus dem Spaltungsverfahren konnten Schlüsse gezogen werden auf die Anzahl der Bestandteile einer Mischung und ihre wahrscheinliche Struktur. Die gegebenen Beispiele zeigen die Brauchbarkeit der Massenspektrometrie für die Analyse von Steringemischen.