Propanone reaction with, phosgene

Reaction of phosgene with the anti isomer of 1-amino-1-phenyl-2-propanone oxime gives l-hydroxy-5-methyl-4-phcny -3-iraidazolin-2-one in 25% yield [49]. A review of A -oxide formation has appeared recently [50], and discussions of other approaches to the compounds are found in Section 4.1 and Chapter 5. 

A military specification [1394a] suggests the determination of phosgene by reaction of phosgene with a solution of sodium iodide in propanone, and titration of the liberated iodine with sodium thiosulfate (see Section 3.2.1.2), correcting for any free chlorine present. 

The reaction of propanone with phosgene appears to be typical of a ketone that is in tautomeric equilibrium with its enol. For example, the heterocyclic derivative (10.23) was... 

Phosgene is an oxidising agent, and iodometric techniques, based upon equation (3.2), have been employed for its determination [425,1148,1255,1357,1604]. The reaction must be carried out under anhydrous conditions (commonly in propanone or methyl ethanoate [1604]), and the iodine determined by conventionai procedures, such as by titration with [S fi 3] Although the usual starch indicator cannot be used in propanone solution, the colour of the generated dliodlne affords a reasonably sharp end-point [1560]. In addition, indications of very smali quantities of phosgene are indicated by the reddish-yellow colour of the liberated diiodine, so that the method can be applied for the trace determination of the gas [1560],... 

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