NOTES
Oct. 20, 1954 Ketimines.
5169
VIII. Infrared Spectra of Ketimines
BY P. L. PICKARD AND G. W. POLLY RECEIVED JUNE 4, 1954
The literature includes much work on the absorption band due to the =Ngroup but in most instances this group is part of a ring. Randall’ has published the spectra of a few oximes, imido ethers, thiazolidines, imidazolines, oxazolones and pyridines. His assignments for the C=N maximum range from 5.89-6.50 p. I n addition to these assigned maxima, Randall obtained the spectra of several guanidines and/or their salts, l-phenyl-3methylpyrazolone-5 and creatinine. From his spectra we have made assignments for the C=N ranging from 5.95-6.29 p (Table I ) . TABLEI
TABLE I1 Ketimine
Bis-(p-chlorophenyl) w-Cyclohexylethyl s-butyl w-Cyclohexylamyl s-butyl Diphenyl O-Tolyl s-butyl Phenyl t-butyl o-Tolyl i-amyl o-Tolyl n-propyl Ethyl n-butyl Di-n-propyl w-Cyclohexylpropyl s-butyl a-Naphthyl phenyl o-Tolyl ethyl O-Tolyl %-butyl o-Tolyl ;-butyl
=N--H
3.08 3.09 3.09 3.09 3.09 3.10 3.10 3.10 3.10 3.10 3.10 3.10 3.12 3.12 3.12
C=N
6.05 6.09 6.09 6.24 6.14 6.18 6.13 6.14 6.08 6.08 6.10 6.24 6.13 6.14 6.15
C=O in corresponding ketone
5.82
..
5.83
..
5.92
.. 5.92 5.93 5.83
.. ..
6.02 5.91 5.92 5.93
Wave length in p for C=N band
region from 6.08-6.10 p. Also, the N-H band occurred from 3.09 to 3.12 p. One aryl alkyl ketimine, in which the alkyl group was tertiary, absorbed at 6.18 p. It is possible that this value might be more nearly that of the imine band and the lower values of 6.136.14 due to overlap with the olefin band from the eneamine form-the latter form being impossible with the tertiary group. However, the band assigned to the imine group is, in every case, quite sharp and shows no indication of being a doublet. As was expected, the increase of wave length of absorption when the imine group is conjugated with Lieber, et a1.,2 have published the spectra of 38 a single aromatic nucleus, was greatly enhanced in guanidine derivatives and assigned values from diary1 ketimines. Diphenyl ketimine and cy5.8-6.15 p for the C=N group. naphthyl phenyl ketimine show strong bands a t I n connection with a long range program of prep- 6.24 p. It was also expected that the presence on aration and characterization of ketimines in this the aromatic nucleus of a “deactivating” group, Laboratory it was desired to establish whether the such as the halogen, would decrease the extent of imino group in these compounds showed character- conjugation, and that absorption would occur a t a istic absorption in the range obtained for the com- shorter wave length than in other aryl ketimines. pounds investigated by other authors. During this Bis-(p-chlorophenyl) ketimine absorbed a t 6.05 p . study Fuson3 published the absorption maxima for ,411 spectra were obtained with the Perkin-Elmer N-benzoylduryl phenyl ketimine (6.14 p ) , N- Model 12C, single beam instrument with NaCl opmethylduryl phenyl ketimine methiodide (6.14 p ) tics, using NaCl cells. The compounds used were and N-methylduryl fi-t-butylphenyl ketimine (6.11 prepared in this Laboratory as reported in previous papers in this series.6 A secondary aim of this investigation was to (6) P. L. Pickard, et QZ., ibid., 72, 878,5017 (1950); 73, 42 (1951); check the possibility of an ene-amine tautomerism 74, 4607 (1952); 76, 5899 (1953). in compounds containing hydrogen alpha to the DEPARTMENT OF CHEMISTRY imino group. This tautomeric equilibrium has been UNIVERSITYOF OKLAHOMA OKLAHOMA hypothesized by Moureau and Mignonac4 and NORMAN, Weissberger and Glass5 to explain certain reaction products of imines. In none of our spectra was there Steroids. LVIII.’ Synthesis of Allopregnaneevidence of the band due to the olefinic linkage. 3P,6P,2 1-triol-20-one Triacetate However, the location of the imine maximum is BY J. ROMO, G. ROSENKRANZ AND F. SONDHEIMER found so near that expected for the olefin that, due to the probability of overlapping, no conclusion RECEIVED MAY21, 1954 could be drawn as to eneaminization. Imines and For certain biological studies we required the the corresponding ketones are given in Table 11. Five dialkyl ketimines were studied, showing triacetate V of allopregnane-3P,6P,2l-triol-20-one, strong bands assigned to the imino group in the an isomer of Reichstein’s substance R with the 1lP-hydroxy group transposed to C-6. The A4( 1 ) H. Randall, el at., “Infrared Determination of Organic Strucunsaturated compound corresponding to V has tures,’‘ D. Van Nostrand, Inc., New York, N. Y., 1949. been described12 but its hydrogenation does not (2) E. Lieber, D. Levering and L . Patterson, Anal. Chem., as, 1594 Compound
Guanidine acetate Aminoguanidine bicarbonate Aminoguanidine sulfate Guanidine carbonate Guanidine thiocyanate Methylguanidine hydrochloride Methylguanidine sulfate Triphenylguanidine sym-Diphen ylguanidine 1-Phenyl-3-methylpyrazolone-5 Creatinine
6.00 5.95 6.05 6.00 6.03 6.00 6.08 6.11 6.10 6.24 6.29
(1951). (3) R. C. Fuson, et al., THISJOURNAL, 75, 5321 (1953). (4) C. hfoureu and G. Mignonac, Coinpt. r e n d . , 158, 1395 (1914). ( 5 ) A. Weissberger and D. Glass, TEISJOWRNAL, 64, 1724 (1942).
(1) Paper LVII, G. Rosenkranz, M .Velasco and F Sondheimer, THISJOURNAL, 76, 5024 (1954). (2) 0 . hlancera, G. Rosenkranz and C. Djerassi, J . Org Chem., 16, 192 (1951).
