The methylation of N-cyano N-methyl hydrazones: A new access to 2-aminoimidazoles through an in situ 1,3,4-triaza cope rearrangement

The reaction of 1-methyl-1-cyanohydrazones with methyl trifluoromethane sulfonate allows the direct preparation of 2-(methylamino)-1-methyl imidazoles as their triflic acid salts. The reaction pathway is believed to involve the formation of the 1-cyano-1,2-dimethyl ene-hydrazine derivative, which then undergoes a [3,3] rearrangement at room temperature, followed by an in situ cyclisation. None of the intermediates could be isolated or observed by H-1 NMR. Thus, the 2-(methylamino)-1-methyl imidazoles are obtained in good to average yields In two steps from the corresponding ketones and 1-methyl-1-cyanohydrazine

Benzimidazolo-diazepines From 1,3-dienes and Arenediazocyanides Through a 1,3,4-tri-aza-cope Rearrangement

Cyclic and bicyclic 1-cyano-2-arylhydrazines were prepared from arene diazocyanides and 1,3-dienes. Some of them rearrange at room temperature through a 1,3,4-triaza-Cope rearrangement, followed by an intramolecular cyclisation, to afford benzimidazolo-diazepines in moderate yields. When the competitive retro Diels-Alder reaction is made impossible by reduction of the cycloadducts, the rearrangement takes place at higher temperatures, with excellent yields, to previously unknown benzimidazolo-diazepines

5-Aminopyrazoles from enolisable ketones and 1-cyano-1-alkylhydrazines.

The reaction of enolisable ketones with 1-alkyl-1-cyanohydrazines leads to the corresponding cyanohydrazones. These compounds cyclise under thermal or mildly basic conditions, furnishing the corresponding 5-aminopyrazoles in good yield. In some cases, the hydrazones cannot be isolated and the pyrazole derivatives are directly obtained. Hydrazone-enehydrazine tautomerism was observed, bat no subsequent [3,3]rearrangement. (C) 1997, Elsevier Science Ltd

Glycomimetic, orally bioavailable LecB inhibitors block biofilm formation of Pseudomonas aeruginosa

International audienceThe opportunistic Gram-negative bacterium Pseudomonas aeruginosa is a leading pathogen for infections of immuno-compromised patients and those suffering from cystic fibrosis. Its ability to switch from planktonic life to aggregates, forming the so-called biofilms, is a front-line mechanism of antimicrobial resistance. The bacterial carbohydrate binding protein LecB is an integral component and necessary for biofilm formation. Here, we report a new class of drug-like low molecular weight inhibitors of the lectin LecB with nanomolar affinities and excellent receptor binding kinetics and thermodynamics. This class of glycomimetic inhibitors efficiently blocked biofilm formation of P. aeruginosa in vitro while the natural monovalent carbohydrate ligands failed. Furthermore, excellent selectivity and pharmacokinetic properties were achieved. Notably, two compounds showed good oral bioavailability, and high compound concentrations in plasma and urine were achieved in vivo

Developments in international bioenergy trade

The aim of this paper is to present a synthesis of the main developments and drivers of international bioenergy trade in IEA Bioenergy Task 40 member countries, based on various country reports written by Task 40 members. Special attention is given to pellet and ethanol trade. In many European countries such as Belgium, Finland, the Netherlands, Sweden and the UK, imported biomass contributes already significantly (between 21% and 43%) to total biomass use. Wood pellets are currently exported by Canada, Finland and (to a small extent) Brazil and Norway, and imported by Sweden, Belgium, the Netherlands, and the UK. In the Netherlands and Belgium, pellet imports nowadays contribute to a major share to total renewable electricity production. Trade in bio-ethanol is another example of a rapidly growing international market. With the EU-wide target of 5.75% biofuels for transportation in 2010 (and 10% in 2020), exports from Brazil and other countries to Europe are likely to rise as well. Major drivers for international bioenergy trade in general are the large resource potentials and relatively low production costs in producing countries such as Canada and Brazil, and high fossil fuel prices and various policy incentives to stimulate biomass use in importing countries. However, the logistic infrastructure both in exporting and importing countries needs to be developed to access larger physical biomass volumes and to reach other (i.e. smaller) end-consumers. It is concluded that international bioenergy trade is growing rapidly, far beyond what was deemed possible only a few years ago, and may in the future in some Task 40 countries surpass domestic biomass use, especially for specific applications (e.g. transport fuels). (c) 2008 Elsevier Ltd. All rights reserved.32871772