Dimethyl sulfoxide-Phosgene

Dimethyl sulfoxide-Phosgene, 58 Palladium(II) trifluoroacetate, 236 Trimethylamine N-oxide, 325 Trimethylsilyl chlorochromate,... 

Dimethyl sulfoxide-Phosgene, 58 Methoxy(phenylthio)trimethylsilyl-me thane, 182... 

Related Reagents. Dimethyl Sulfoxide-Oxalyl Chloride Dimethyl Sulfoxide-Phosgene Dimethyl Sulfoxide-Tri-phosgene. 

Related Reagents. Dimethyl Sulfoxide-Acetic Anhydride Dimethyl Sulfoxide-Dicyclohexylcarbodiimide Dimethyl Sulfoxide-Methanesulfonic Anhydride Dimethyl Sulfoxide-Oxalyl Chloride Dimethyl Sulfoxide-Phosgene Dimethyl Sulfoxide-Phosphorus Pentoxide Dimethyl Sulfoxide-Sulfur Trioxide/Pyridine Dimethyl Sulfoxide-Tiifluoroacetic Anhydride Dimethyl Sulfoxide-Triphosgene. 

One potential activator for dimethyl sulfoxide that in practice turns out to be very poor, is phosgene. However, a related oxidation of alcohols using dimethyl sulfoxide does use phosgene for the preparation of a chloroformate (or carbonochloridate) such as (29). - This reacts with dimethyl sulfoxide to give, after spontaneous loss of carbon dioxide, an alkoxysulfonium salt (30) which upon treatment with tri-ethylamine fonns the carbonyl compound (Scheme 7). Relatively little use appears to have been made of this method. 

Flammable Liquid, Corrosive SAFETY PROFILE Poison by inhalation. Moderately toxic by ingestion. A human systemic irritant by inhalation. Violent hydrolysis reaction with water or steam produces heat, acetic acid, HCl, and other corrosive chlorides. May decompose during preparation. Dangerous fire hazard when exposed to heat or flame. Explosion hazard by spontaneous chemical reaction with dimethyl sulfoxide or ethanol. Also incompatible with PCI3. When heated to decomposition it emits highly toxic fumes of phosgene and Cl . To fight fire, use CO2 or dry chemical. See also CHLORIDES. 

The maiin domain of oxidation with dimethyl sulfoxide is the conver-sionofprimary alcoholsinto aldehydes andofsecondaryalcoholsintoketones. These reactions are accomplished under very mild conditions, sometimes at temperatures well below 0 °C. The reactions require the presence of acid catalysts such as acetic anhydride [713, 1008, 1009], trifluoroacetic acid [1010], trifluoroacetic anhydride [1011, 1012, 1013], trifluorometh-anesulfonic acid [1014], phosphoric acid [1015, 1016], phosphorus pentox-ide [1006, 1017], hydrobromic acid [1001], sulfur trioxide [1018], chlorine [1019, 1020], A -bromosuccinimide [997], carbonyl chloride (phosgene) [1021], and oxalyl chloride (the Swem oxidation) [1022, 1023, 1024], Dimethyl sulfoxide also converts sufficiently reactive halogen derivatives. into aldehydes or ketones [998, 999] and epoxides to a-hydroxy ketones at -78 °C [1014]. 

A modification of alcohol oxidation with dimethyl sulfoxide is the reaction of DMSO with alkyl chloroformates, which are formed from alcohols and phosgene (equations 220 and 221) [1021]. 

Barton devised a new method for the oxidation of primary alcohols to aldehydes involving in the first step conversion to the alkyl chloroformate (1) by adding a solution of the alcohol in ether to ether saturated with phosgene (15-20% w./v.) the solvent is removed at reduced pressure. If the alcohol is hindered, quinoline is added as catalyst and the quinoline hydrochloride removed by filtration. The next step, reaction with dimethyl sulfoxide, is attended with evolution of carbon... 

Dehydration Alumina (see also Dihydropyrane, preparation). Boric acid. Boron triSuoride. N-Bromoacetamide-Pyridine-SOj. Dicyclohexylcarbodiimide. Diketene. Dimethylform-amide-Thionyl chloride. Dimethyl sulfoxide. Ethylene chlorophosphite. Florisil. Girard s reagent. Hydrobromic acid. Iodine. Mesyl chloride-Sulfur dioxide. Methyl chlorosulfite. Methylketene diethylacetal. Naphthalene-d-sulfonic acid. Oxalic acid. Phenyl isocyanate. Phosgene. Phosphorus pentoxide. Phosphoryl chloride. Phthalic anhydride. Potassium bisulfate. Pyridine. Thionyi chloride. Thoria. p-Toluenesulfonic acid. p-Toluenesulfonyl chloride. Triphenylphosphine dibromide. 

However, the facile reaction between dimethyl sulfoxide and phosgene (see Section 10.6.5.1) makes this a questionable postulate. 

TRICHLORACETIC ACID (76-03-9) C2HCI3O2 Combustible liquid [flash point (solid material) >230°F/>110°C]. Generally stable if moisture is not present in elevated temperatures, this material, combined with H2O forms HCl and deadly phosgene gases. The aqueous solution is a strong acid. Incompatible wifli sulfuric acid, bases, ammonia, amines, dimethyl sulfoxide, iso-... 

HAZARD RISK Dangerous fire hazard when exposed to heat or flame contact with strong oxidizers may cause fire vapors may flow to distant ignition sources and flash back forms explosive mixtures with powdered sodium or phosphorus trichloride and sodium violent reaction with silver perchlorate and dimethyl sulfoxide closed containers exposed to heat may explode decomposition emits toxic gases of hydrogen chloride, phosgene, carbon monoxide, carbon dioxide NFPA Code H 2 F 3 R 0. 

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