Carbonimidoyl dihalides

Iminophosphoranes can also be used to synthesize symmetrical carbodiimides. In this case they are reacted with carbon dioxide, thereby mimicking the synthesis of carbodiimides from amines and carbon dioxide. Another useful synthesis of unsymmetrical carbodiimides, not requiring the use of carbonyl chloride, is the reaction of carbonimidoyl dihalides with amines. The synthesis and chemistry of carbonimidoyl halides was reviewed in 1968. ... 

Heating of carbonimidoyl dihalides with amines or amine hydochlorides affords carbodi-imides. For example, heating of trifluoromethylcarbonimidoyl difluoride 120 with amines produces the corresponding trifluoromethyl substituted carbodiimides 121. ... 

Carbonimidoyl dihalides Imidoyl halides Haloformamidines Haloformimidates Halothioformimidates Hydroxamoyl halides Hydrazidoyl halides... 

The carbonimidoyl dihalides are derivatives of the hypothetical carbonimid acid HN=C(OH)2, and Chemical Abstracts uses the term imidocarbonyl dihalides for compounds I. Recently, the more appropriate name carbonimidoyl dihalide was advanced and it will be used in this monograph. 

The synthesis of carbonimidoyl dihalides is not limited to compounds having the N=CX2 group attached to aliphatic and aromatic hydrocarbyl and heterocyclic moieties. Acyl ( 11 125 aroyl (4.55,56,114,125 fonyl (5.7,32,37,1 1 1,1 15 phosphoryl carbonimidoyl dichloridesC " ) have been synthesized, and a variety of other combinations can certainly be visualized. A recent survey of syntheses of carbonimidoyl dichlorides has been published by Kiihle and his co-workers... 

The availability of several synthetic procedures has prompted extensive investigation of the reactive carbonimidoyl dihalides, especially by Holtschmidt (49.54a Kiihle ( 6.95a Farbenfabriken Bayer, A.G., and by Kodama et al. (69-83 Mukaiyama and his colleagues (35,io4-io6 in Japan. 

The reactions of carbonimidoyl dihalides can be divided into nucleophilic substitution reactions, whereby the halo groups are replaced stepwise by other nucleophiles, and addition reactions. The substitution reactions are often accompanied by elimination, depending upon the stability of the formed imidoyl derivatives. For example, the monosubstitution products can eliminate hydrogen halide, alkyl halide, or sulfenyl chloride, i.e.,... 

The addition to the C=N bond is limited to reactive species, such as hydrogen halides, carbonyl fluoride and organometallics, and seems to proceed well only with carbonimidoyl difluorides. The dehalogenation of carbonimidoyl dihalides by triphenylphosphine provides a useful method to generate isocyanides, which are sometimes difficult to obtain by Hofmann s classical method. 

All in all a great variety of compounds can be synthesized from carbonimidoyl dihalides, and their use as agricultural chemicals has been indicated in the patent literature (17,27,29,48,65,88,94,99.144 ... 

Similarly, addition of bromine and iodine to phenyl isocyanide yields the corresponding crude carbonimidoyl dihalides however, Nef... 

One example of the conversion of a secondary amine to the corresponding carbonimidoyl dihalide was reported by Young and his colleagues who heated bis(trifluoromethyl)amine (LX) and obtained trifluorocarbon-imidoyl difluoride (LXI) and hydrogen fluoride. Upon chlorination of LX with phosphorus trichloride, the corresponding dichloride (LXII) was obtained... 

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)... 

Asymmetrical Vibration Stretching of the C=N Group in Carbonimidoyl Dihalides... 

The C=N stretching vibrations for several groups of carbonimidoyl dihalides are listed in Table VIIL... 

The reaction of carbonimidoyl dihalides with primary and secondary amines proceeds stepwise to yield chloroformamidines CVIII and guanidines CIX respectively 9,24,28,36,42,56,64,73.92,95a,los, 110,114-117.124,133,137,i40j... 

Thus, reaction of carbonimidoyl dihalides with a wide variety of nitrogen-containing substrates can be achieved, and the products obtained range from linear chloroformamidines, guanidines, and carbodiimides to five- and six-membered heterocycles. 

In the reaction of the mercury derivative CXXVI with CINO2, a mixture of the nitramine CXXVII and the carbonimidoyl dihalide CXXVIII is obtained ( ). 

Abstraction of the halo groups from carbonimidoyl dihalides (reversal of their syntheses) to yield isocyanides can be achieved by the use of triphenyl and tributylphosphine... 

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