Oxidizing agents selenium trioxide

Methyl-2-vinylbenzofurans also undergo cycloaddition with acetylenic dienophiles, but ready aromatization of the products is blocked by the angular methyl group. It can, however, be achieved by oxidizing agents, such as selenium dioxide or chromium trioxide, or even by exposure to air (Scheme 35). Mechanisms for these reactions have been postulated. 

Liriodenine can also be prepared by oxidation of the aporphine unshinsunine (Id) 14 16) or roemerine (le) with chromium trioxide in pyridine 14). Other oxidizing agents which afford hriodenine from ushinsunine are acidic potassium permanganate, selenium dioxide, and selenium 15). A superior method involves the air oxidation of a potassium tertiary butoxide in i-butyl alcohol solution of anonaine (If) 17). 

SELENIUM TRIOXIDE (13768-86-0) OjSeNoncombustible solid. Violent reaction with water, forming selenic acid. A strong oxidizer. Violent reaction with many substances including reducing agents, hydrides, nitrides, and sulfides cyanides, esters, combustible materials, active metals, organic substances, aldehydes, alkenes, carboxylic acids, isocyanates, and thiocyanates. Attacks most metals in the presence of moisture. 

Chromium trioxide and certain other chromium(VI) compounds are useful as strong oxidizing agents in the laboratory, but appropriate precautionary measures should be taken when conducting these reactions. Chromium trioxide has been reported to react violently with a variety of substances, including readily oxidized organic compounds such as acetone, acetaldehyde, methanol, ethanol, diethyl ether, ethyl acetate, acetic acid, and DMF, and violent reactions may also occur on reaction with alkali metals, gaseous ammonia, phosphorus, and selenium. 

Sulfur trioxide is produced from the catalytic oxidation of the dioxide. Its trigonal planar structure requires three resonance structures to describe. The very short S-0 bond distances seem to indicate that there are strong dir-fm interactions in addition to the expected delocalized fnr bonds. It is a powerful oxidizing agent. Although selenium and tellurium are less stable in the +6 oxidation state than is sulfur, both Se03 and Te03 can be prepared. 

ACETATO MERCURIOSO (Spanish) (21908-53-2) A strong oxidizer. Violent reaction with reducing agents, acetyl nitrate, diboron tetrafluoride, disulfur dichloride, combustible materials, fuels, hydrazine hydrate, hydrogen peroxide, hydrogen trisulfide, hypophospho-rous acid, methanethiol, phospham. sodium-potassium alloy, sulfur, sulfur trioxide. Incompatible with alcohols, alkali metals, ammonium nitrate, diboron tetrafluoride, hydrazinium nitrate, hydrogen sulfide, nitroalkanes, rubidium acetylide, selenium oxychloride. Forms heat-, friction-, or shock-sensitive explosives with anilinium perchlorate, chlorine, phosphorus,. sulfur, magnesium, potassium, sodium-potassium alloy. May increase the explosive or thermal sensitivity of nitromethane, nitroethane, 1-nitropropane and other lower nitroalkanes, silver azide, hydrazinium perchlorate. Slowly decomposes on exposure to air. 

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