Roger W. Read

Bio: Roger W. Read is an academic researcher from University of New South Wales. The author has contributed to research in topics: Alkyl & Meisenheimer complex. The author has an hindex of 19, co-authored 72 publications receiving 998 citations.

Trifluoromethanesulfonic anhydride–4-(N,N-dimethylamino)pyridine as a reagent combination for effecting Bischler–Napieraiski cyclisation under mild conditions: application to total syntheses of the Amaryllidaceae alkaloids N-methylcrinasiadine, anhydrolycorinone, hippadine and oxoassoanine

Abstract: A combination of triflic anhydride and 4-(N,N-dimethylamnino)pyridine effects Bischler–Napieraiski cyclisation of β-phenethytearbamates and β-phenethylamides under very mild conditions.

Explosive Meisenheimer complexes formed by addition of nucleophilic reagents to 4,6-dinitrobenzofurazan 1-oxide

Abstract: The reaction between 4,6-dinitrobenzofurazan 1-oxide (1) and a number of nucleophilic oxygen and nitrogen reagents has been studied. The exceptional electrophilic power of (1) leads to formation of 1 : 1 Meisenheimer complexes as the general reaction observed. Ammonia and hydrazine also form bis-adducts in the presence of excess (1). All the adducts were isolated as stable, but highly explosive, cystalline solids, and have been characterized by micro-analysis and spectroscopy. The adducts from N3- and I- have been observed spectroscopically but not isolated. The monomethoxy adduct (8) undergoes a novel internal oxidation-reduction to form a gem-dimethoxybenzofurazan complex(6).

Synthesis and functionalization of indoles through palladium-catalyzed reactions

Abstract: The substituted indole nucleus [indole is the acronym from indigo (the natural dye) and oleum (used for the isolation)] is a structural component of a vast number of biologically active natural and unnatural compounds. The synthesis and functionalization of indoles has been the object of research for over 100 years, and a variety of well-established classical methods are now available, to name a few of them, the Fisher indole synthesis, the Gassman synthesis of indoles from N-halo-anilines, the Madelung cyclization of N-acyl-o-toluidines, the Bischler indole synthesis, the Batcho-Leimgruber synthesis of indoles from o-nitrotoluenes and dimethylformamide acetals, and the reductive cyclization of o-nitrobenzyl ketones.1 In the last 40 years or so, however, palladiumcatalyzed reactions, generally tolerant of a wide range of functionalities and therefore applicable to complex molecules, have achieved an important place in the arsenal of the practicing organic chemist. Since the invention of an industrial process for the palladium-catalyzed production of acetaldehyde from ethylene in the presence of PdCl2 and CuCl2, an everincreasing number of organic transformations have been based on palladium catalysis. Almost every area of the organic synthesis has been deeply influenced by the profound potential of this versatile transition metal, modifying the way organic chemists design and realize synthetic processes.2,3 Because of its catalytic nature, palladium-catalyzed synthesis can provide access to fine chemicals, agrochemical and pharmaceutical intermediates, and active ingredients in fewer steps and with less waste than classical † In memory of Prof. Bianca Rosa Pietroni, a colleague and very close friend. * To whom correspondence should be addressed. Phone: + 39 (06) 4991-2785. Fax: + 30 (06) 4991-2780. E-mail: sandro.cacchi@ uniroma1.it. 2873 Chem. Rev. 2005, 105, 2873−2920

Inhibition of quorum sensing in Pseudomonas aeruginosa biofilm bacteria by a halogenated furanone compound.

Abstract: Novel molecular tools have been constructed which allow for in situ detection of N-acyl homoserine lactone (AHL)-mediated quorum sensing in Pseudomonas aeruginosa biofilms. The reporter responds to AHL activation of LasR by expression of an unstable version of the green-fluorescent protein (Gfp). Gfp-based reporter technology has been applied for non-destructive, single-cell-level detection of quorum sensing in laboratory-based P. aeruginosa biofilms. It is reported that a synthetic halogenated furanone compound, which is a derivative of the secondary metabolites produced by the Australian macroalga Delisea pulchra, is capable of interfering with AHL-mediated quorum sensing in P. aeruginosa. It is demonstrated that the furanone compound specifically represses expression of a PlasB-gfp reporter fusion without affecting growth or protein synthesis. In addition, it reduces the production of important virulence factors, indicating a general effect on target genes of the las quorum sensing circuit. The furanone was applied to P. aeruginosa biofilms established in biofilm flow chambers. The Gfp-based analysis reveals that the compound penetrates microcolonies and blocks cell signalling and quorum sensing in most biofilm cells. The compound did not affect initial attachment to the abiotic substratum. It does, however, affect the architecture of the biofilm and enhances the process of bacterial detachment, leading to a loss of bacterial biomass from the substratum.