Cyanogen chloride, tetrameric

The carbonimidoyl dichloride structure VI was established recently for tetrameric cyanogen chloride (69.72,131,133 compound which can also be synthesized by chlorinating 2-dimethylamino-4,6-dichloro-l,3,5-triazine VII ( ). 

Tetrameric cyanogen chloride has been used to synthesize a great variety of 1,3,5-triazine derivatives (69-83.131.i33j... 

However, the reaction proceeds preferentially via route (a), as evidenced by the isolation of 72 % of the tetrameric cyanogen chloride XXXVIII. The triazine derivative XXXVIII can also be obtained by chlorination of the corresponding isothiocyanate C% A somewhat lower yield of the triazinyl-bis-carbonimidoyl chloride was obtained in the chlorination of 2,6-bis(di-methylamino)-4-chloro-l,3,5-triazine ( ). If cyclic carbamoyl chlorides, or carbamoyl chlorides having alkyl substituents other than methyl are chlorinated, the expected imidoyl chlorides are obtained For... 

Perhaps the most direct formation of a carbonimidoyl dihalide involves the tetramerization of cyanogen chloride. Although cyanuric chloride, the trimer, is the main product of the oligomerization of cyanogen chloride, yields up to 39 % of the tetramer LXIV can be obtained under controlled conditions (60.69.72.131.133)... 

The reaction of carbonimidoyl dichlorides with excess water results in complete hydrolysis with formation of the corresponding amine and carbon dioxide ( ). This reaction affords isocyanate as an intermediate, as evidenced by the isolation of 1,3-diphenylurea from the reaction mixture, obtained by treating phenylcarbonimidoyl dichloride with water In the reaction of tetrameric cyanogen chloride with water at 20°C 2-amino-4,6-dichloro-l,3,5-triazine (LXXXVI) is obtained, whereas at 100 C total hydrolysis to cyanuric acid (LXXXVII) occurs... 

This reaction has been used to convert tetrameric cyanogen chloride to the corresponding triazinyl isothiocyanate which upon reaction... 

Perhaps the best method for conversion of carbonimidoyl dichlorides into isocyanates consists of their reaction with one equivalent of sodium methoxide, followed by thermolysis. Thus, Kodama and Sekiba obtained the triazinyl isocyanate CXXXII from tetrameric cyanogen chloride via the intermediate CXXXIII. Since N-heterocyclic isocyanates cannot be synthesized by direct phosgenation, this method may have general applicability. 

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