Showing papers by "Govindasamy Mugesh published in 2002"
TL;DR: The differences in the stability and reactivity of the organochalcogen compounds derived from various substrates are described in terms of electronic and stereochemical properties of donor atoms.
Abstract: Chiral and achiral organochalcogen compounds bearing a heteroatom in close proximity are easily accessible via the directed aromatic lithiation route. The lithium chalcogenolates prepared by the insertion of selenium or tellurium into the C-Li bond are used to synthesize various chalcogen compounds such as Se/Te, N donor ligands, dichalcogenides, monomeric metal chalcogenolates, and macrocycles. The differences in the stability and reactivity of the organochalcogen compounds derived from various substrates are described in terms of electronic and stereochemical properties of donor atoms.
163 citations
TL;DR: In this article, a series of diaryl ditellurides with and without coordinating amino/imino groups are synthesized by using either the Grignard route or the heteroatom-directed aromatic lithiation route.
83 citations
TL;DR: Treatment of this compound with aromatic thiols and thiobenzoxazole in the presence of NEt3 affords areneselenenyl sulfides that are stable towards disproportionation reactions, and the high reactivity of the selenenyl iodide with the seenol suggests that a reduced selenol group may react with the E−SeI intermediate to produce a diselenide without any thiol cosubstrate.
Abstract: Enzyme mimetic studies on the crucial intermediate (E-SeI) of the iodothyronine deiodinase cycle have been carried out by using an areneselenenyl iodide stabilized by intramolecular Se···N interactions. Treatment of this compound with aromatic thiols and thiobenzoxazole in the presence of NEt(3) affords areneselenenyl sulfides that are stable towards disproportionation reactions. The structures of three of the areneselenenyl sulfides were determined by X-ray crystallography. In one case, in the absence of NEt 3 , a diselenide can be formed rather than the selenenyl sulfide. The areneselenenyl iodide also reacts with a related selenol to produce the corresponding diselenide, and this reaction is found to be much faster than that with thiols. The high reactivity of the selenenyl iodide with the selenol suggests that a reduced selenol group (R'-SeH) may react with the E-SeI intermediate to produce a diselenide (E-Se-Se-R') without any thiol cosubstrate. The intermediacy of selenenyl sulfides during the reduction of selenenyl iodide by thiols and its possible relevance to the iodothyronine deiodinase catalytic cycle is also described.
36 citations
TL;DR: A structure - activity correlation between natural GPx and some existing mimics is described, in an attempt to draw some general concepts for the development of new mimics.
Abstract: Among the organoselenium compounds that mimic the action of the natural enzyme glutathione peroxidase (GPx), there are certain basic differences in the activity, substrate specificity and mechanism. These differences arise mainly from the nature of the substituents near the reaction center, and stability and reactivity of the intermediates. As an attempt to draw some general concepts for the development of new mimics, a structure - activity correlation between natural GPx and some existing mimics is described.
9 citations
TL;DR: C9H7NO2Se as discussed by the authors has an intramolecular Se⋯O contact of 2.5614Õ(15)ÕA and an intermolecular SE contact of 3.271Ò(2)ÒA.
Abstract: The title compound, C9H7NO2Se, displays an intramolecular Se⋯O contact of 2.5614 (15) A and an intermolecular Se⋯N contact of 3.271 (2) A. The molecule is approximately planar, the substituents being rotated by ca 5° out of the ring plane.
4 citations
TL;DR: In this paper, the differences in the stability and reactivity of the organochalcogen compounds derived from various substrates are described in terms of electronic and stereochemical properties of donor atoms.
Abstract: Chiral and achiral organochalcogen compounds bearing a heteroatom in close proximity are easily accessible via the directed aromatic lithiation route. The lithium chalcogenolates prepared by the insertion of selenium or tellurium into the C-Li bond are used to synthesize various chalcogen compounds such as Se/Te, N donor ligands, dichalcogenides, monomeric metal chalcogenolates, and macrocycles. The differences in the stability and reactivity of the organochalcogen compounds derived from various substrates are described in terms of electronic and stereochemical properties of donor atoms.
1 citations