[10405-27-3] · F2HN · Difluoramine · (MW 53.01)
Alternate Name: fluoroimide.
Physical Data: bp -23 °C.
Preparative Methods: difluoramine can be generated from tetrafluorohydrazine, which is made by reaction of NF3 with various metals at 375 °C.6 Conversion into difluoramine is accomplished by heating tetrafluorohydrazine with Thiophenol in an evacuated bulb.7 Difluoramine is also generated by heating N,N-difluorourea with conc. Sulfuric Acid.8
Handling, Storage, and Precautions: is shock sensitive. Reactions should be carried out in a fume hood.
The reaction of t-octylazomethine or t-butylazomethine with difluoramine has been shown to give diazirine (eq 1).4 Other substituted imines produce substituted diazirines, a-fluoroazo compounds, or a-fluoroalkylidene hydrazines in relative yields dependent upon the structure of the imine (eq 2).9
Difluoramine reacts with aldehydes and ketones to give a-difluoroamino alcohols of varying stability (eq 3).1 Aliphatic ketones and aldehydes react with difluoramine in H2SO4 or oleum with replacement of the carbonyl by two difluoroamino groups (eq 4).2
Carbocation precursors in the g-position cyclize to give difluoroamino substituted lactones (eq 5) and tetrahydrofurans.2 Michael addition of difluoramine takes place with a,b-unsaturated carbonyl compounds (eq 6).
Difluoramine undergoes reaction with a-hydroxy ketones and 1,2-diketones in fuming H2SO4 to form 4-difluoroamino or 4,5-bis(difluoroamino) substituted 1,3-dioxa-2-thiolane 2,2-dioxides, respectively (eq 7).8 Difluoramine is generated in situ by the interaction of N,N-difluorourea with concentrated H2SO4 in these reactions. Difluoramine reacts vigorously with acetone phenylhydrazone to give N-fluorodimethylketimine (eq 8).10
The reaction of 3-hexyne with difluoroamine, catalyzed by the Boron Trifluoride complex of Phosphoric Acid, gives 3-hexanone, 3,3-bis(difluoroamino)hexane, 3-difluoroamino-3-fluorohexane, and N-(a-difluoroaminopropyl)propionamide in various yields.11
Difluoramine can be alkylated with an alkyl halide, alcohol, alkene, or ether to yield difluoroamino substituted alkanes.3 Ether derivatives require no catalysis; with alkenes the boron trifluoride complex of phosphoric acid or H2SO4 is used (eq 9). Yields are sensitive to time and temperature and range from 50-60 % for the alkene reactions to quantitative for the ethers.
Difluoramine converts primary amines to alkanes (eq 10). Secondary amines, such as aziridine, azetidine, and dibenzylamine, react with difluoramine to yield, respectively, ethylene (eq 11), cyclopropane, and bibenzyl by releasing nitrogen and coupling the remaining fragments.5,12
The reaction of difluoramine with C-nitroso compounds affords N-substituted N´-fluorodiimide N-oxides (eq 12); N-aryl substituted N´-fluorodiimide N-oxides can be converted to azoxy compounds with Grignard reagents (eq 12).13
Ankara University, Turkey