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3912
Vol. 83
of substitut.ed cycloheptai~es~ observed in per- azoisobutyroiiitrilc, azoisobutane, and hexaphtnylhydrctazulenes.R The application of this rearrange- ethane also reacted with N2F4 to produce the corriieiit to the svnthesis of seven-menibered aromatic responding difluoratniii~s, I , b.p. 71-72' (1 50 mni ), coiiii)ounds is now ill progress. 11,b.p. 54-53'and H I , 1i1.p.81-82' We are irictc1)ted to Prof. F. Sondheirner for his (CHa)?C--NF? ( C M T ) ~ C N F ~ (C611G)jC XI'? interest and eiicourageinent, and to Syntex S.A., , Mexico, for a generous gift of starting materials, CN and optical rotatory dispersion measurements. I I1 Ill (7) H . J . I?. 1,newenthal atid R . Kona, J . Chcin. Soc , 1429 (1961), and refs. cited therein. (8) N I,, Allinfier and V . B . Zalkow, J . A m . C h e m . hoc., 83, 1144 (IQGl).
Satisfactory analyses were obtained for a11 these compounds. Their F19 n.ni.r. spectra6 all show signals from the NF, groups a t -44724, -4224, and - 4430 c.P.s., respectively. These compounds resist T H E DANIEL SIISI'I~ JlESEARCH INSTITUTE T H E b'EIZMANN 1XSTITCTE OF SCIENCE YEHUDA MAZUR hydrolysis. I i ~ r r o v o r r r ,ISRAEL MANASSE NUSSIM N,N-Difluoramides also may be obtained by the RECEIVED J u L y 10, 1961 reaction of aldehydes with NzF4. N,N-Difluoroacetamide and difluoramine were produced when acetaldehyde arid N2F4 were heated a t 150' in a Pyrex TETRAFLUOROHYDRAZINE: A VERSATILE INTERMEDIATE FOR THE SYNTHESIS OF N-FLUOR0 bulb. This reaction may be compared to the conCOMPOUNDS version of benzaldehyde to benzoyl chloride by Sir: chlorine.' We have found tetrafluorohydrazine,' NzF4, to be 150' CHaCMO f NnFd ----+ CHjCONFz + HNF, a versatile intermediate for the synthesis of both IV organic and inorganic compounds containing the difluoramino group, NF2. N2F4participates in a NzF4 must be handled cautiously. Oxygen must variety of free radical reactions as might be ex- be excluded rigorously from mixtures of N2F4 and pected from its low N-N bond strength.2 organic compounds or explosions are likely to result. NzF4 and chlorine react under the influence of The difluorarnino compounds themselves should ultraviolet light in Pyrex to produce chlorodifluor- also be handled with care. ClNF2. This is an equilibrium reaction in Acknowledgment.-This work was conducted which the formation of chlorodifluoramine is under Army Ordnance Contract DA-01-021 ORDfavored by a large excess of chlorine and a relatively 5135. The support and encouragement of Dr. high temperature (80'). The synthesis of difluorD. Niederhauser is gratefully acknowlWarren amine, HNF2, by the hydrogen abstraction reacedged. tion between NzF4 and thiophenol has been re(7) C. Walling, "Free Radicals in Solution," John Wiley and Sons, p~rted.~ The photolysis of diketones in the presence of Inc., New York, N. Y . , 1957, p. 369. ROBERTC PETRY AND I l A A S COMPANY NzF4 a t room temperature in Pyrex caused the ROHM KEDSTONE ARSENALRESEARCH DIVISION formation of N,N-difluoroamides in good yield. JEREMIAH P. FREEMAN FT IJNTSVII,LE, ALABAMA 00
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CARBONIUM ION SALTS. 11. REACTION OF
WITH INORGANIC HALIDES ; The reaction has beeti applied successfully to biace- CYCLOHEPTATRIENE TROPENIUM CHLOROBORATE' tyl, glyoxal and benzil. For example, 0.06 mole of There is much interest in compounds of the chlobiacetyl and 0.06 mole of NzF4irradiated for sixteeii hours with a Hanovia EH-4 lamp yielded 0.077 roborate anion2a-i; however, their preparation has required high temperature and pressure,2d long mole of N,N-difluoroacetamide (IV), b.p. 45-47'; yield 80% based on N2F4consumed. -4nal. Calcd. milling of solids,2hor liquid hydrogen chloride solFound; N , 14.40. vent,2g and the products often give unsatisfactory for C2H3F2NO: N, 14.74. The material was characterized by its infrared analyses. The only easily prepared, stoichiometric spectrum (yc-0 1820 cm.-l>, n.1n.r. spectrums (FL9 chloroborate reported is cesium chloroborate. 2 i . 3 We find that the reaction of boron chloride with resonance a t -4270 C.P.S. and H' resonance a t 4in methylene chloride (dry condi190 c.P.s.), and by its solvolysis in ethanol to ethyl ~ycloheptatriene~ tions under nitrogen, room temp. for 24 hr., mole acetate and difluoramine. Alkyl radicals6 generated by the decomposition of ratio BCl3/C7Hs of 1.4/1) gives 12.6% tropenium (1) C. B . Colburn and A . Kennedy, J . A m . Chem. Sac., 80, 5004 (19i58). (2) C. B. Colburn and F . . A . Johnson, J . Chem. P h y s . , 33, 1869 (I9GO). (3) R . C . Petry, J . A m . Chem. Soc., 82, 2400 (1900). (4) J . P. Freeman, A. Kennedy and C . B . Colburn. i b i d . , 82, 8304 (1960). (5) Flu resonauces are recorded in cycles from external CFsCOiH and HI resonances from external C&a. Negative values indicate resonance a t lower field than the standard. 16) The photochemical reaction between alkyl iodides and NaF, prestimably involves alkyl radicals; J. W. Frazer, J . Inorg. X f l c ! . C h v ! w , , 16, 6 3 ( l ! X O ) .
(1) Supported b y the Petroleum Research Fund, Grant 443-A. (2) (a) D. R. Martin, Chem. Rcu.. 42, 581 (1948); (b) N. N.Greenwood and K . Wade, J . Chem. Sac., 1527 (1956); (c) M . F. Lappert, Proc. Chem. SOC.,121 (1957); (d) E. L. Muetterties, J . A m Chem. S O C . , 79. 65fi3 (1957); (e) A. B. Burg and E. R. Birnbaum, J . Inarg. N d . Chem., 7 , 146 (1958); ( f ) D. E . Burge, H. Freund and T. H. Norris, J . P h y s . C h e m . , 63, 1969 (1959); ( 6 ) T. C. Waddington and F. Klanberg, N o l u r v i s s , 20, 678 (1959); J . Chem. SOC.,2329, 2332 (1960); (b) W. Kynastron, B . E. Larcombe and H. S. Turner, ;bid., 1772 (1960); (i) E. L. Muetterties, J . Inarg. Nucl. Chem.. 12, 355 (lg60). (3) LappertZ0 has reported the preparation of pyridinium chloroborate but does not give experimental or analytical details. (4) Generoilsly supplied by the Shell Chemical Company.
