Diazirines difluorodiazirine

Among unsaturated C—N—N three-membered rings only the 3H-diazirines (3) are known. IH-Diazirines with a C=N double bond were never obtained. Diazirines with one or two alkyl groups at carbon were prepared in many cases, aryldiazirines only in some cases. An important role is played by difluorodiazirine as well as by diazirines containing chlorine or bromine (9). 

There are some reports on reactions involving complete N—N cleavage in diazirine reactions such as formation of amidine (205) from chlorophenyldiazirine, or on formation of products containing only one nitrogen atom. Betaine (206) was described as a product from difluorodiazirine and triphenylphosphine. Compound (207) is formed from decomposing (204) and cyclohexane (79AHC(24)63). 

Diazirine-3,3-dicarboxylic acid, 1080 Difluorodiazirine, 0342 Dipotassium diazirine-3,3-dicarboxylate, 1340 3-Fluoro-3-(trilluoromethyl)-3//-diazirine, 0631 3-Methyldiazirine, 0808 3,3-Pentamethylenediazirine, 2422 Potassium hydrogen diazirine-3,3-dicarboxylate 3-Propyldiazirine, 1594... 

In the case of diazirines, both difluorodiaztrine and bis(trifluoromethyl)diazirine have been obtained. Difluorodiazirine was originally prepared by reductive defluorination of bis(difluoroamino)difluoromethane [320, 321], but it can also be obtained by an interesting fluoride-ion-induced rearrangement of difluorocyanamide [322] (Figure 8.125). Bis(trifluoromethyl)diazirine [318, 323] is best obtained by the oxidation of 2,2-diaminohexafluoropropane, prepared from hexafluoroacetone, with sodium hypochlorite (Figure 8.126). 

Chemically, difluorodiazirine appears to be remarkably inert. Like diazirine itself, however, it is explosive. It undergoes thermal decomposition above about 160°C. Photolysis of this compound at room temperature produces only tetrafluoroethylene and nitrogen, presumably by the reactions... 

An interesting subject is the influence of substituents on the relative stability of the corresponding diazomethane and diazirine derivatives, because there is a qualitative indication that difluorodiazirine is more stable than difluorodiazomethane. 

Prepared by lead tetraacetate oxidation of the corresponding diaziridine, bis(trifluoromethyl)diazirine (263) has also been made by hypochlorite oxidation of hexafluoroacetone aminal 262. Instead of by oxidation, ring formation in the case of difluorodiazirine (265) has been achieved by mild reduction of bis(difluor-... 

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