FLUORIXATION OF D D T
h'ov. 20, 1957
WITH
HYDROGEN FLUORIDE AND
blEKCUKIC
OXIDE
5979
[FROMTHE RESEARCH LABORATORIES. ARMYMEDICAL CORPS, ISRAEL DEFENCEFORCES]
On the Fluorination of DDT with Hydrogen Fluoride and Mercuric Oxide BY SASSON COHEN,ASHERKALUSZYNER AND RAPHAEL MECHOULAM RECEIVEDJUXE 10, 1957 The fluorination of D D T with mercuric oxide and anhydrous hydrogen fluoride does not give 11, b u t V, by a rearrangement reaction. A number of compounds related t o D D T have been treated analogously, and the corresponding rearrangement has been observed for l,l-di-(~-~hlorophenyl)-1,2,2,2-tetrachloroethane ( X I ) which gives compounds X I 1 and X I I I .
In 19-16, Kirkwood and Dacey' studied the fluori- (chromic acid in glacial acetic acid, alcoholic sonation of 1,l-di-(p-chlorophenyl)-2,2,2-trichloroeth-dium hydroxide, sodium methoxide) . Refluxing it ane (DDT) (I) with anhydrous hydrogen fluoride for 2 hr. with sodium ethoxide solution causes the in the presence of mercuric oxide. They obtained elimination of hydrogen fluoride, yielding a coma compound CI4HYCI2F3 melting a t G4", to which they pound C14H&F2 which must be 1,2-di-(p-chlorophenyl) -1,2-difluoroethylene (VI) because of its attributed formula 11. composition, the similarity of its ultraviolet specH trum with that of 4,4'-dichlorostilbene (see Fig. 1) C ~-lJ--(C -l I -
__
I1 C
l
-
H
VI: 224 (4.34), 294 (4.60), 306 (4.62) (in alc.) 4,4'-Dichlorostilbeiie: 229 (4.28), 303 (4.53), 317 (4.53) (in alc.)
CF3 OH
and its ready oxidation to p-chlorobenzoic acid. If one excludes an intramolecular rearrangement in the treatment of Kirkwood and Dacey's cornpound with sodium ethoxide, the formation of V I
cc13
I
~
-
L
111
CFa F
11.
CHFz
~
-
C
I
c ~ __ - ~ - c F ~ c H F - ~ - c ~ 11
the carbinol I11 has been prepared and reduced to a compound which undoubtedly has structure I1 but is different from Kirkwood and Dacey's compound; it melts a t 45". Its structure follows from the presence of the CFa bands3 in its infrared spectrum, its easy conversion into di(p-chlorophenyl)-acetic acid4 and a second synthesis from (p-chloropheny1)-trifluoromethylcarbinol and chlorobenzene. Kirkwood and Dacey's compound must, therefore, have a different struct~re.~ As we have-repeating the experiment of the Canadian authors-been able to confirm the formula C14H9C12F3,only two structures (IV and V) appear to be possible, which are isomeric to 11. Both these formulas explain the absence of the CF, bands in the infrared spectrum of the substance. The compound has proven very stable to the usual agents employed in degradation experiments 1. R. Dacey, Can. J . Res., 24B, 69 (1946). (2) A . Kaluszyner, S. Reuter and Is. D. Bergmann, THISJ O U R N A L , 77, 4184(1956). (3) For literature, see ref. 2 , footnote 9. (4) R. Mechoulam, 3 . Cohen and A. Kaluszyner, J . Oug. Chein., 21, 801 (1956). ( 5 ) It should be recalled that the insecticidal activity and fat solubility of the compound of Kirkwood and Dacey were used to support a theory of the mode of action of DDT; see, e.g., S. Kirkwood and P. H. Phillips, J . Pkarmatol. E x # . T h e r a p . , 87, 375 (1946); E. F. Rogers, H. D. Brawn, I. M . Rasmussen and I
