Diphosgene Chloroformate

Phosgene, as well as the easier to handle diphosgene (chloroformic acid trichloromethyl ester) or triphosgene (carbonic acid bis(trichloromethyl) ester) transform primary, secondary and tertiary amides and thioamides to chloromethyleneiminium chlorides (25 equation 15), whereby the reaction with thioamides is of broader scope and proceeds with fewer side reactions. The amide chlorides derived from primary and secondary amides can lose HCl, giving nitriles or imidoyl halides, respectively. /V-Sub-stituted formamides can be converted to isonitriles via amide halides. ... 

Diakyl carbamyl chlorides Diakyl aluminum hydrides Diborane Dibromoketone Dichloromethyl chloroformate Diphosgene Fuming nitric acid Gngnard reagents Hydrides nonvolatile... 

Trichloromethyl chloroformate (diphosgene) is used as a safe substitute for highly toxic phosgene gas. The latter is generated in situ by addition of catalytic amounts of tertiary amines or amides, or active carbon. Diphosgene also disproportionates to 2 equivalents of phosgene on heating above 250°C. 

R Katakai, Y Iizuka. An improved rapid method for the synthesis of N-carboxy a-amino acid anhydrides using trichloromethyl chloroformate. (diphosgene). J Org Chem 50, 715, 1985. 

Diphosgene, trichloromethyl chloroformate C13C0C(0)C1 Reported as an alternative to the use of oxalyl chloride with the advantage of being a dense liquid with low volatility262... 

Another preparatively valuable multiple chlorination is the photochemical perchlorination of methyl chloroformate, which leads to diphosgene ... 

Scheme 9 Reaction of an Amino Acid with Trichloromethyl Chloroformate (Diphosgene) To Produce N-Carboxyanhydrides...

The preference of the Germans during the war of 1914-18 for employing trichloromethyl chloroformate (diphosgene) rather than... 

Green Cross Gases. This includes substances with a high vapour tension and great toxic power on the respiratory tract phosgene, trichloromethyl chloroformate (diphosgene), chloro-picrin, etc. 

Chlorination of methyi chloroformate and dimethyl carbonate affords useful phosgene substitutes chloromethyi chioroformate [I], trichioromethyl chloroformate [II] also called Diphosgene and bis(trichloromethyi) carbonate [III] known as Triphosgene [see scheme 33] ... 

The reversibility of the decomposition of Diphosgene into carbon tetrachloride and carbon dioxide is still a controversial topic. However, the production of phosgene by reaction of carbon tetrachloride and carbon dioxide over catalysts such as Lewis acids was recently claimed in Russian patents (Ref. 32). The reaction is assumed to proceed through the formation of trichloromethyl chloroformate or bis(trichloromethyl) carbonate. 

Phosgene can be replaced with either diphosgene or triphosgene in the same conditions to give the corresponding 1-alkyl chloroformates in very good yields (Ref. 61). 

Trichloromethyl chloroformate (DP, diphosgene) was first used in the summer of 1915. It eventually replaced monochloromethyl chloroformate in German gas shells and was used extensively through the end of the war. 

Interestingly, the chloroformate (diphosgene) and the carbonate (triphosgene) react with pyridine to give the same product (see also Chapter 12). The material described as (py)j. jCOClj, prepared from the reaction of phosgene with pyridine in benzene solution, was noted to lose half a molar equivalent of pyridine upon standing over PjOj in vacuo [1809a]. 

The compound reacts with alcohols, phenols and amines to form products similar to those obtained from the corresponding reaction with COCI [1358]. Depending upon the conditions and stoicheiometry, carbonates and chloroformates [612,1380], carbamates [1380], isocyanates [1184] and ureas [938] can be obtained with diphosgene, in addition to more complicated products such as carbamoyl chlorides, imidic chlorides, carboxylic acid chlorides, isonitriles and IV-carboxy-Q-amino acid anhydrides [1358]. 

Diphosgene has not been prepared from phosgene itself, but its detailed preparation from the action of dichlorine on methyl chloroformate has been described [1184]. However, diphosgene is now readily available commercially from regular suppliers. 

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