Lewis acid 69 Nitric oxide

S / V CONTENTS Preface, Robert W. Hay. Structure and Function of Manganese-Containing Biomolecules, David C. Weather-bum. Repertories of Metal Ions as Lewis Acid Catalysts in Organic Reactions, Junghan Suh. The Multicopper-Enzyme Ascorbate Oxidase, Albrecht Messerschmidt. The Bioinorganic Chemistry of Aluminum, Tomas Kiss and Etelka Farkas. The Role of Nitric Oxide in Animal Physiology, Anthony R. Butler, Frederick Flitney and Peter Rhodes. Index. 

Anthraquinone itself is traditionally available from the anthracene of coal tar by oxidation, often with chromic acid or nitric acid a more modern alternative method is that of air oxidation using vanadium(V) oxide as catalyst. Anthraquinone is also produced in the reaction of benzene with benzene-1,2-dicarboxylic anhydride (6.4 phthalic anhydride) using a Lewis acid catalyst, typically aluminium chloride. This Friedel-Crafts acylation gives o-benzoylbenzoic acid (6.5) which undergoes cyclodehydration when heated in concentrated sulphuric acid (Scheme 6.2). Phthalic anhydride is readily available from naphthalene or from 1,2-dimethylbenzene (o-xylene) by catalytic air oxidation. 

Nitration of an aromatic ring138 to give ArNOa is most often carried out with nitric acid in sulfuric acid however, concentrated nitric acid, aqueous nitric acid, and nitric acid in polar organic solvents are also commonly used, as is preliminary nitrosation followed by oxidation of the aromatic nitroso compound (ArNO). Alkyl nitrates (R0N02) are also nitrating agents in the presence of some Bronsted and Lewis acids.139... 

There is considerable evidence that nitric oxide is a Lewis acid. In this type of interaction electron density is accepted into the 7r-antibonding molecular or-... 

Alkyl Nitrites. An exchange reaction (19) between NO and EtO NO proceeds through a BNO intermediate or transition state. The exchange is first-order in nitric oxide and first-order in alkyl nitrite. Two possible mechanisms were proposed (19), both of which involve NO behaving as a Lewis acid ... 

Resonance forms for the sulfite ion have not been included. There has been discussion concerning whether the compound should be considered a sulfonated hyponitrite (16) or a nitrosated hydroxylamine sulfonate (9). The compound can be prepared by nitrosating a sulfonated hydroxylamine (9). There is little to be gained by this dispute, for the structure is best described as in the above diagrams or in molecular orbital terminology. The reaction of sulfite ion and nitric oxide is best considered as a Lewis acid-base reaction in which nitric oxide behaves as the acid and sulfite ion as the donor. A reaction sequence can be formulated with the following equations ... 

Primary, Secondary, and Tertiary Amines. It has been demonstrated (12, 13) that nitric oxide behaves as a Lewis acid toward a large number of primary and secondary amines. The reactions with primary and secondary amines can be generalized by the following scheme ... 

TRIOXAPENTADECANE (112-73-2) C12H26O3 Combustible liquid (flash point 245°F/118°C oc autoignition temp 590°F/310°C Fire Rating 1). Reacts violently with oxidizers, permanganates, peroxides and hydroperoxides, ammonium persulfate, bromine dioxide, sulfuric acid, nitric acid, perchloric acid, and other strong acids Lewis acids including aluminum chloride, boron trifluoride, iron(III) chloride, niobium pentachloride, and ytterbium(III) triflate. Incompatible with acyl halides. 

NO" is also a strong Lewis acid and forms adducts with donors which do not oxidise readily, e.g. Me2SO. Formally the nitrosyl halides shown in 6 may be viewed as NO" adducts of the halide anions X. The independent chemistry of reduced nitric oxide (NO ) is limited, and it probably has an extremely short independent life in biological media [1, 6]. NO is a Lewis base, which is isoelectronic with O2 and formally forms adducts with Lewis acids such as giving angular HNO. 

SO2 and CO, CO2, N2O, NO2, and H2O. Lippard and coworkers also utilized the Lewis acid-base interaction for fluorescent detection of nitric oxide (NO). Fluorophores (dansylimidazole or dansylpiperazine) bind to the axial site of the metal center in a dirhodium tetracarboxylate complex. Displacement of fluorophores by NO causes a fluorescence change. 

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