COMMUNICATIONS TO THE EDITOR
3156
Vol. SI
bonds. The possibility that linkages other than disulfide bonds are involved has not been excluded.
polymer (m.p. 2.50’ with decomposition; found: C, 50.76; H, 6.88; X, 19.34). From the filtrate the cyclic trimer, 1,3,5-triethyl isocyanurate, was isoTHEROCKEFELLER ISSTITUTE XETV YORK, AT. Y . GERALD M. EDELMAN lated and identified by its solubility and melting (m.p. 94’) characteristics. RECEIVEDAPRIL24, 1959 Ethyl 1-Nylon was soluble in trifluoroacetic acid (TFA) and concentrated sulfuric acid. Clear T H E HOMOPOLYMERIZATION films were obtained when TFA solutions were air OF MONOISOCYANATES dried and extracted with methanol a t room temSir: perature. Prolonged standing of the polymer in Beyond the formation of cyclic dimers’ and tri- TFA resulted in degradation: a change in the mers* from monoisocyanates (Reactions I and I1 inherent viscosity a t 0.57c concentration from U.3 in Fig. 1) and the suggestion that cyamelide3 is to 0.04 occurred in two days. Light scattering a linear polyisocyanic acid, there has been no studies on the aged solution gave a molecular evidence to indicate the possibility of obtaining weight value of 1600-3000 ( i e . , a D.P. of 23 to addition polymers from monofunctional compounds 42).j The polymer was further characterized by its containing >C=Ngroups. I have recently distinct infrared spectrum where the only significant found that monoisocyanates can be polymerized bands were those corresponding to carbonyl a t to linear high molecular weight polymers in a man- 5.85p, K,N-disubstituted amide at 7 . 4 ~and a ner similar to vinyl compounds in accordance with conspicuous absence of isocyanate aiid N H bands.:’ the Reaction I11 in Fig. 1. These polymers may b 3 t h phenyl isocyanate, a polymer (1n.p. 197’ be regarded as N-substituted “1-nylons.” with decomposition) was obtained in 8GYc yield in N,N-dimethylformamide using the sodium catalyst4” a t -40’. The polymer was soluble in concentrated sulfuric acid, but insoluble in TFX and chlorinated hydrocarbons. I t s infrared spectrum was consistent with a phenyl 1-Nylon structure and DIMER II,3-DIPHENYL URETIDENEDIONE) quite distinct from either the dimer or trimer of phenyl isocyanate. II
c
(,i) T h e author n-ishes t o th:rnk Drs. D . Akeley and R . Zbindcn for t h e light scattering d a t a and infrared analysis, respectively.
c
HEAT OR GONG. H Z S 0 4
POLYMER TRIMER
(PHENYL-I
PIOYEERISG RESEARCH LABORATORY 1-ICTOR E. SIIASIIOUA TEXTILE FIBERS DEPARTMENT E. I. DU POXT DE KEDIOURS & Co., I s c . ~VIL~WNGTOS, DELAWARE RECEIVED A r m , 28, 1959
NYLON)
lI,3,5-TRIPHENYL ISOCYANURATE)
Fig. 1.-Reactions
of phenyl isocyanate.
The polymerization takes place a t low temperatures (-20’ to -looo) in polar solvents, such as N,N-dimethylformamide, N,N-dimethylacetamide and triethylamine, through the use of anionic initiators. Ethyl isocyanate and phenyl isocyanate, examples of an aliphatic and aromatic isocyanate, were polymerized in the manner to be described. Ethyl isocyanate, 25 ml., and dry triethylamine, 25 ml., both previously cooled to -40°, were stirred together rapidly under dry nitrogen, and further cooled to -100’ with liquid nitrogen. Next 10 ml. of a sodium catalyst solution in N,N~limethylforniamide~was added to the rapidly stirring solution during about 30 seconds. A white, fibrous solid precipitated immediately upon contact of the catalyst with the monomer solution. The solid was filtered off, washed with methanol and dried to give 8.5 g. (39Yc) of ethyl 1-Nylon ( 1 ) A. W.IIoEmann, B e y . , 3, 765 (1870). ( 2 ) D. H . Chadmkk and T. C. Allen, U.S . Patent 2.733,25-4 (1956). ( 3 ) W.Kern, H. Paul a n d W. Mehren, Makuo7nol. C h e m . , 14, 140 (1954). (1) (a) T h e cntalyst solution was prepared h y adding 10 drops of a 50% sodium dispersion in xylene (du P o n t Electrochemicals DeI,artmeni) tc, ;10 nil. of dry r,P;-dimethyIformamide. T h e mixture v3;ts stirred for 1 h o u r before use. (b) T h e use of this combination :is a catalyst for the anionic pulymerization for \-iuyl compounds was demonstrated by L. Grandine. E. I. d u P o n t de Nemours 8s Company (private communication).
STEROIDS. CXXII.‘ 6o-FLUORO-16a-METHYLCORTICOIDS-SYNTHESIS AND BIOLOGICAL ACTIVITY
Sir: Among the most recent chemical modificatiolis of the hydrocortisone and prednisolone molecule-resulting in increased anti-inflammatory activity and diminution of salt retention-have been introducor addition of a methyl tion of a 6a-fluorine atom’s2j3 group in the 16a-position.4~~We now wish to report the synthesis and preliminary biological evaluation of analogs of the most important cortical hormones combining both of these structural features. The preparation in this Laboratory of Ga-fluuro1Ga-methylhydrocortisone acetate (I) nia Ga-fluoro16a-methyl “Substance S” already has been recorded.6 Dehydration of I with mesyl chloride in (1) Paper CXXI, A. Bowers, 1s. Denot, hI. R. Sknchez and 11 J . Itingold, Tclrahedyox, in press. (2) A. Bowers a n d €1. J . Iiinjinld, THISJoirRN.4r., 80, 442:1 (1!1,->8). ( 3 ) J. A. Hogg, G . B. Spero, J. I,. Thompson, B. J. M a g c r l r i i i W. P. Schneider, D. H. Peterson, 0. K. Sebek, 1%.C. Rliirray, J . C . Hahcock, R.L. Pederson and J. A . Campbell, Chm7istry and I m l u s l r Y 1002 (1958).
(4) G. E. Arth, J. Fried, D. R . R. Johnston, D. R. Huff, L . H. Snrett. R. H. Silber, H. C. Stoerk and C. A. XVinter, THISJ O U R N A L , 80, 3 1 l i l (1958). (.j) E. P. Olireto.
R. R Iiiisrr, I,. lyeber, A . 1.. Niisshmrn, lV. Gebert, C. T. Conigliri, E. 13. Hcrshberx, S. T d k s d u r f , hi. Rider, 1’. J,. I‘erlman and h l . hf. I’echet. i b r < l ,80, $ 4 3 1 (1058). (6) J. A. Ed\\-ards. b. ZafT.ir(mi. H. J. I
