A simple, efficient and highly diastereoselective one-pot three-component synthesis of functionalized 2,6-disubstituted-4-tosyloxytetrahydropyrans was performed. The synthesis features an optimized Prins cyclization in which an aromatic homoallylic alcohol, an aromatic/aliphatic aldehyde, and p-toluenesulfonic acid (catalyst and reagent) are reacted in the presence of molecular sieves (MS) 4 Å ...

We have developed a new method to prepare 4-acetoxy substituted 5(4H)-oxazolones by direct oxidation of N-benzoyl amino-acids using hypervalent iodine. The method is efficient, economical and easy to perform for the synthesis of quaternary substituted amino acid derivatives. We used online FTIR monitoring techniques to analyze the reaction, and gave a plausible reaction mechanism.

One of the leading power companies in Denmark, Elsam Kraft A/S, has proposed a vision of the Danish energy sector (end of 2004), with a working title ’’From petrol to REtrol’’ (originally ‘‘From benzin to VEnzin’’, vedvarende = renewable, in Danish). The vision points to changes in the energy sector from being based on combined production of electricity and heat to one based on combined product...

The assessment of behavioral changes produced by prenatal or early postnatal exposure to potentially noxious agents requires both the designing of ad hoc tests and the adaptation of tests for adult animals to the characteristics of successive developmental stages. The experience in designing tests is still more limited than in the adaptation of tests, but several tests have already proven their...

An application of so-called perception-based logical deduction in the modeling of an economic analysis given in natural language is presented. Fuzzy IF-THEN rules and theory of evaluating linguistic expressions are used, and possibilities of automated reasoning are outlined.

Let G∞ = (C d m)∞ denote the graph whose set of vertices is {1, . . . ,m}d, where two distinct vertices are adjacent iff they are either equal or adjacent in Cm in each coordinate. Let G1 = (C d m)1 denote the graph on the same set of vertices in which two vertices are adjacent iff they are adjacent in one coordinate in Cm and equal in all others. Both graphs can be viewed as graphs of the d-di...

Let t(n, d) be the minimum number t such that there are t of the n lattice points {(x1, . . . , xd) : 1 ≤ xi ≤ n} so that the ( t 2 ) lines that they determine cover all the above n lattice points. We prove that for every integer d ≥ 2 there are two positive constants c1 = c1(d) and c2 = c2(d) such that for every n c1n d(d−1)/(2d−1) ≤ t(n, d) ≤ c2n log n. The special case d = 2 settles a proble...

Article history: Received 21 April 2008 Received in revised form 13 May 2009 Accepted 14 May 2009 Available online 27 May 2009 This paper assumes that the decision makers of OPEC (or at least of its core members) are interested in both profits and political payoffs (support, popularity, being a hero of the Arab or Islamic street, etc.). The oil weapon, i.e. a reduction of output is the most pow...

abstract in the 7th and 8th centuries of hijri, kish island had been the maritime trade center of the persian gulf under the reign of  bani gheisar government, and any changes in this area has affected the neighboring areas and further lands. the objective of this essay is to study the economic changes of kish island and its excellent position in the maritime trade of the persian gulf, oman sea...