Gas Liquid Chromatography of Phenanthrenes Use in Identification of the Components of Mixtures of Alkyl Phenanthrenes A. J. SOLO' and
S. W. PELLETIER2s3
The Rockefeller Institute, New York 2 I , N. and University o f Georgia, Athens, Ga.
b The relative retention times of 60 alkyl phenanthrenes have been determined on a variety of columns. The relative retention times determined on the nonpolar liquid phase SE-30 and on the polur liquid phase QF-10065 have been factored in a manner which permits the prediction of relative retention times of alkyl phenanthrenes on these phases. The data presented facilitate the identification of small amounts of phenanthrenes obtained from the degradation of natural products.
T
HOUGH drastic dehydrogenation has
long been recognized as an important approach t o the elucidation of the skeletal structures of natural products (8), the method has remained subject to extreme experimental difficulties arising both from low yields and from the complexity of the mixtures usually produced. In a recent communication (9), we presented data indicating the possibility of separating and identifying typical components of such mixtures by gas liquid chromatography (I, I, 7). We have concentrated our study on the alkyl phenanthrenes because of the importance of these compounds t o work on the di- and higher terpenoids and because successful application of the method to phenanthrenes makes obvious its utility in simpler series. The identification of new alkyl phenanthrenes, such as obtained from the dehydrogenation of natural products, has in the past presented a difficult problem, particularly when, as often happens, too little material is isolated to permit structure deteminations by chemical degradation. Infrared and ultraviolet spectral studies can limit the number of structures which need be considered, at least by showing the presence or absence of certain nuclear-subPresent address, School of Pharmacy, State University of New York a t Buffalo, Buffalo 14, N. Y. Present address, Department of Chemistry, University of Georgia, Athens, Ga. To whom in uiries concerning this paper should be aidressed.
1584
b
ANALYTICAL CHEMISTRY
Y., School of Pharmacy,
Stute University o f New York a t Buffalo, Buffalo 7 4, N.
stitution patterns (6). Nuclear magnetic resonance spectrometry can also be of great help, especially with respect to determining the number and nature of the alkyl substituents. The problem could be further simplified if the relative retention times of unknown or unavailable phenanthrenes could be predicted. The treatment outlined in this paper permits the prediction of relative retention times of alkyl phenanthrenes on two phases. EXPERIMENTAL
Equipment. All runs were made on either a n Aerograph A-110-C equipped with a thermal conductivity detector or a n Aerograph A-600-B equipped with a flame ionization de-
tector. A Brown-Honeywell l-mv. full scale recorder was used with both instruments. All columns used were obtained from the Wilkens Instrument and Research Corp., Walnut Creek, Calif. Materials. The phenanthrenes studied were obtained from the following sources:
F. A. L. b e t , Universit of California a t Los Angeles. g-n-ButyLhenanthrene, 9-isobutylphenanthrene. P. M. B. Bavin, Smith Kline and French Laboratories, Welwyn Garden City, Herb fordshire, England. 4Methylphenanthrene, 4,5-methylenephenanthrene(ex Leights), 3,6-dimethylphenanthrene,9,lOdimethylphenanthrene (ex Bradsher), 3ethylphenanthrene, 9-n-propylphenanthrene, 9,1O-diethylphenanthrene, 9450butylphenanthrene, 9 - tert - amylphenanthrene, 9-cyclopentylphenanthrene, 9benzylphenanthrene, 9,lO - dehydrophe. . nanthrene. C. K. Bradsher, Department of Chemistry, Duke University. 9-Methylphenanthrene, 9,10-dimethylphenanthrene, 9ethvlohenanthrene. 9 methvl - 10ethjiiphenanthrene; 9 isoplopylphenanthrene, 9-n-butylphenanthrene, 9-ethyl10-n-propylphenanthrene, 9-methyl-lO-nbutylphenanthrene, 9-ethyl-10-phenylphenanthene. R. C. Cambie, University of Auckland, New Zealand. 1,2,8-Trimethylphenan. . _ . threne. E. Chandrose, Bell Telephone Labora tories, Murray Hill, N. J. 1,7-Dimethylphenanthrene, 1.4.7 . . - trimethylphe_ _ hanthrene. ' C. Djerassi, Department of Chemistry, Stanford University. 4Ethylphenanthrene.
--
Y.,
0. E. Edwards, Division of Pure Chemistry, National Research Council, Ottawa, Canada. l16,7-Trimethylphenanthrene. L. F. Fieser, Department of Chemistry, Harvard University. 2,BDimethylphenanthrene, 24ertbutylphenanthrene, 3-tertbutylphenanthrene. W. J. Gensler, Department of Chemistry, Boston University. 1,2,7,8-Tetramethylphenanthrene, 1,7,8,9-tetramethylphenanthrene. . E. B. Hershberg, Schering Corp., Bloomfield. N. J. 1-Ethvl-2.8-dimethvlohe" , nanthrene. W. A. Jacobs, Rockefeller Ipstitute. 1Methylphenanthrene, 1,6-dimethylphenanthrene, 1,7-dimethylphenanthrene, 1methyl-7-isopropylphenanthrene, fluorene, 1'-methyl-1 ,2 - cyclopentanophenanthrene, 1.2.8-trimethvl~henanthrene(ex N. L. Drake). F. E. King, T. J. King, and J. W. W. Morgan, Forest Products Research Laboratory, Prince Risborough, Ayiesbury, Bucks, England. l,&Dimethylphenanthrene, 1,3,8 - trimethylphenanthrene, l,4,S - trimethylphenanthrene, 2,4,8trimethylphenanthrene, 1-methyl-8-ethylphenanthrene. B. J. Mair, Petroleum Research Laboratory, Carnegie Institute of Technology. 3 Methylphenanthrene, 1,s - dimethylphenanthiene. E. Mosseti N.I.A.M.D., National Institutes of &alth. Bethesda. Md. 2Ethylphenanthrene, '9-ethylphehanthrene. M. S. Newman, Department of Chemistry, Ohio State University. 4,5-Dimethylphenanthrene, 2,7 - dimethylphenanthine. E. Ochiai and T. Okomoto, Faculty of Pharmaceutical Sciences, University of Tokvo. 1.9-Dimethvluhenanthrene. 1.3dimethylphenanthre;eJA 1 6,7 trimethylphenanthrene, 1 - methyi - 8 - ethylphenanthrene, 2 - is0 ropylphenanthrene, 1,3-dimethyl-7-ethylpRenanthrene, 1,3,9trimethyl - 7 ethyl henanthrene, 1,2dimethyl-6-isopro ylpffenanthrene, 1,3-d1methyl-7,9-diethy?phenanthrene, 1,3,9-trimethyl-7-isopropylphenanthrene. F. Pioszi, Politecnico di Milano. 1Methylphenanthrene, X-methylphenanthrene, 3-methylphenanthrene, 2-ethylphenanthrene, 1 - methyl - 7 - ethylphenrtnthrene. r -).. L. Turner, Jefferson Medical College, Philadelphia. lJ2-Dimethylphenanthrene. W. B. Whalley, School of Pharmacy, Universitv of London. 1,6,10-Trimethylphenanthkene. S. W. Pelletier. 1,bDiniethylphenanthrene, 1-methyl-ðylphenanthrene, 1-methyl-6-isopro yl henanthrene. Eastman KodaE Phenanthrene. With the exception of several of the compounds of highest molecular weight (which appear to be over 70% pure and '
. I _
__
-
-
-
&.
Table 1.
Relative Retention Times of Alkyl Phenanthrenes
SE-30a Phenanthrene 9,lO-Dihydrophenanthrene 1-Methylphenanthrene 2-Methylphenanthrene 3-Methylphenanthrene 4-Methylphenanthrene 9-Methylphenanthrene
4,5-Methylenephenanthrene
1,2-Dimethylphenant hrc :ne 1,3-Dimethy lphenanthrc :ne
1,6-Dimethylphenanthrcm.e 1,7-Dimethylphenanthrc:ne 1,s-Dimethy1phenanthrc:ne 1,9-Dimethylphenanthreme 2,3-Dimethylphenanthrcne 2,7-Dimethylphenanthrc?ne 3,6-Dimethylphennnthrc:ne 4,5-Dimethylphenanthrcae
9,lO-Dimethylphenanttrr entr 2-Ethylphenanthrene 3-Ethylphenanthrene 4-Ethylphenanthrene 9-Ethylphenanthrene 1,2,8-Trirnethylphenanthrene ll3,8-Trirnethylphenanthrene 1,4,7-Trimethylphenanthrene 1,4,8-Trimethylphenanthrene 1,5,7-Trimethylphenanthrene lJ6,7-Trimethylphenanthrene 1,6,10-Trimethylphenanthrene
1.00 0.756 1.52 1.40 1.37 1.48 1.48 1.48 2.36 2.05 2.09 2.13 2.28 2.14 2.17 1.97 1.88 1.57 2.50 1 .89
1.78 1.73 1.86 3.57 3.06 3.05 3.19 3.01 3.27 3.45 2.69 1-Methyl-6-ethylphenanthrene 1-Methyl-7-ethylphenanthrene 2.83 1-Methyl-8-ethylphenanthrene 2.81 9-Methyl-10-ethylphenmthrene 2.82 2.25 2-Isopropylphenanthren e 9-Isopropylphenanthrene 2.14 94-Prop ylphenanthrene? 2.33 5.44h 1,2,7,8-Tetramethylpheianthrene 1,7,8,9-Tetramethylpheilsnthrene 5 . 13h l-Ethyl-2,8-dimethylpht?nanthrene 4 . I1 1,3-Dimethyl-7-ethylpht:nanthrene 3.80 9,lO-Diethylphenanthrene 3.23 1-Methyl-6-isopropylphenanthrene 3.06 1-Methyl-74sopropylphenanthrene 3.33 1'-Methyl-l,2-cyclopent anophenanthrene 3.95 2-iert-Butylphenanthrene 2.75 3-fert-Butylphenanthre~e 2.45 94-Butylphenanthrene 3.19 9-Isobutylphenanthrene 2.55 1,3,9-Trimethyl-7-ethylphenanthrene 5.24 1 2-Dimethyl-6-isopropylphenanthrene 4.90 1,3-Dirnethyl-7-isopropylphenanthrene 4.62 9-Methyl-10%-butylphfnanthrene 4.70 9-Ethyl-lO+propylphenanthrene 3.95 9-iert-Amylp henanthrene 3.39 9-C clopentylphenanthrene 5.76 IJ3-6imethyl-7,9-diethylphenanthrene 6.02 1,3,9-Trimethyl-7-isopropylphenanthrene 6.01 9-Bem ylphenenthrene 9.35 9-Ethyl-10-phenylp henanthrene 9.12 Fluorene 0.55 ~
Calcd. SE-30 1.00 1.51 1.40 1.37 1.44 1.48 2.38 1.98 2.08 2.12 2.28 2.18 2.16 1.97 1.89 2.46 1.87 1.78 1.73 1.86 3.59 2.99 3.05 3.28 3.05 3.27 3.44 2.69 2.83 2.87 2.75 2.23 2.14 2.33 5.65 5.43 4.03 3.71 3.18 3.11 3.37 2.75 2.45 3.18 2.55 5.00 4.89 4.43 4.71 3.99 3.39 6.76 6.28 5.97 9.35
QF-lb 1.oo
0.553 1.50 1.43 1.39 1.39 1.48 1.40 2.42 2.02 2.08 2.14 2.19 2.10 2.29 1.96 1.94 1.14 2.48 I .80 1.69 1.49 1.75 3.60 2.88 2.72 2.60 2.67 3.41 3.37 2.59 2.72 2.56 2.67 2.05 1.90 2.09 5.46 4.99 3.61 3.66 2.85 2.79 3.06 3.71 2.54 2.26 2.63 2.23 4.85 4.45 4.15 4.12 3.40 2.64 5.15 5.31 5.34 8.05 5.88 0.46
Calcd. QF-1 Dow l l c Dow 710d APL.
NPGSf
NPGP
1.00
1.00
1.00
1.00
1.00
1.00
1.50 1.43 1.40 1.27 1.48
1.44 1.38 1.33
1.37
1.58
1.46
1.51 1.35 1.33 1.45 1.50
2.43 1.96 2.09 2.13 2.17 2.11 2.26 1.97 1.95 2.4s 1.81 1.71
1.49 1.73 3.52 2.85 2.72 2.77 2.72 3.39 3.51 2.56 2.70 2.47 2.66 2.05 1.90 2.09 5.55 5.22 3.67 3.55 2.83 2.77 3.07 2.54 2.26 2.65 2.23 4.62 4.50 4.03 4.08 3.42 2.64 5.15 5.41 5.25 8.05
1.33
1.30
1.78 1.98
1.72
2.31
I , 7c;
2.76
2.30
3.33
2.50 2.59
1.98
2.77
1.93
2.05 2.29
I .G6
1.29 1.29 2.69 1.73 1.63 1.55 1.75
2.26 2.37 1.77
3.03 2.79 3.05 3.59
2.14 2.31 2.98
4.24
3.10 3.49 4.43
2.36 2.58 3.5G
4.46
3.28
2.59 2.69 2.83 I .89
2.92 2.87
3.95 0.56
0.56
0.48
0.43
0.42
10 foot X l/* inch 0.d. stainless steel column packed with 20% SE-30 silicone on 60/80 mesh Chromosorb W, T = 240" C.; P = 42 lb. N2; flame ionization detector. * 10 foot x l/sinch 0.d. stainless steel column packed with 20% QF-1-0065 fluorosilicone on 60/80 mesh Chromosorb W, T = 215' C.; P = 52 lb. Nz: flame ionization detector. c 10 foot X-1/, inch 0.d. stainless steel column packed with 25% Dow-11 silicone on 35/80 mesh Chromosorb, T = 235' C.; P = 16 lb. He; thermal conductivity detector. d 10 foot X l/, inch o.sd. stainless steel column packed with 25% Dow-710 phenyl silicone on 35/80 mesh Chromosorb, T = 294.5' C.; P = 16 lb. He; thermal conductivity detector. * 5 foot X 1/4 inch o d . stainless steel column packed with 25% Apiezon L on 35/80 mesh Chromosorb, T = 235.5' C.; P = 17.3 lb. He; thermal conducivity detector. f 5 foot X l/d inch stsinless steel column packed with 20% neopentyl glycol succinate on 60/80 mesh firebrick, T = 230" C.; P = 24 lb. He; thermal conductivity detector. 0 5 foot X inch strbless steel column packed with 20% neopentyl glycol succinate on 60/80 mesh firebrick, T = 225" C.; P = 48 lb. N2; flame ionization detector. * Data obtained by Rajindra Aneja. (1
VOL. 35, NO. 11, OCTOBER 1963
1585
/
IC.GRLL*Tl\iii-iUilOh
-,.j.:
/
CY NPGIAT22jt
Figure 1. Log relative retention time determined on NPGS Compounds arranged in order of increasing retention times Phenanthrene (at origin) 3-Methyl2-Methyl1 -Methyl2-Ethyl1,7-Dimethyl1 -Methyl-7-ethyC 1 -Methyl-7-isopropyl-
were not available in sufficient quantities for further purification), all saniples used for the determination of relative retention times were over 90% pure as judged from their behavior on GLC over SE-30 and QF-1-0065 phase using a flame ionization detector. Determination of Relative RetenBefore being used, tion Times. columns mere preconditioned by being heated overnight, in a slow stream of nitrogen or helium, t o a temperature at least 50' C. above t h a t employed for the determination of relative retention times. -411 determinations were made by injecting a solution of
Table II.
2 LOG R E L A ' I /E K[TE'IlIO
Figure 2. Dow 1 1
*
Compounds arranged in order of increasing retention times Phenanthrene (at origin) 3-Methyl2-Methyl1 -Methyl2-Ethyl1,7-Dimethyl1 -Methyl-6-ethyl1,4,7-Trimethyl1 -MethyC6-iropropyl1 -Methyl-7-isopropyl1 -Methyl-l,2-cyclopentano1,3-Dimethyl-7-isopropyl-
fluorene, phenanthrene, and alkylphenanthrene in xylene or pyridine into a superheated block connected to the appropriate column. I n runs made on the Aerograph A-1 10-C equipment, retention times were measured as the difference in time between the emergence
Log Factors for Calculating LogloRelative Retention Time of Alkyl Phenanthrenes SE-30 QF-1-0065 Xuclear position Nuclear position l(8) 2(7) 3(6) 4(5) 9(10) 1(8) 2(7) 3(6) 4(5) 9(10) 0.179 0.147 0.138 0.158 0.170 0.175 0.154 0.145 0.105 0.169 0.279 0.272 0.250 0.238 0.269 0.231 0.257 0.233 0.173 0.237 0.349 0.313 0.330 0.312 0.268 0.279 0.367 0.320 0.405 0.354 0.439 0.389 0.407 0.349 0.503 0.424 0.422 0.530 0.712 0.760 0.906 0.971
ANALYTICAL CHEMISTRY
I
Si 0
Log relative retention time on SE-30 and
Group Methyl Ethyl Isopropyl n-Propyl tert-Butyl Isobutyl n-Butvl tert-ilmj-1 Cyclopentyl Benzyl To determine loglo relative retention time of an alkyl phenanthrene, add to sum of the appropriate factors any of following correction terms which may be pertinent: On SE-30 On QF-1 +0.056 Vicinal di Me +0.050 Vicinal di Me +0.056 1,lO-di Me $0.050 1,lO-di Me +0.056 8,9-di Me +0.050 +0.018 Vicinal Me-Et (or larger) 0 -0.023 Vicinal di Et ( or 1nrger ) -0.035 -0,027 1,a-dialkyl -0.020 6,8-dialkyl -0.027 -0.020 6$-dialkyl -0,027 1,g-dialkyl -0.020 1,9-dialkyl -0.027 8,lO-dialkyl -0.020 8,lO-dialkyl -0.027 ?,lo-dialkyl -0.020 2,lO-dialkyl -0,027 - 0 ,n2n i,g-dialkyl 7,S-dialkyl -0,013 I ,8-dialkyl -0.013 2,7-dialkyl
1586
J I TIVL OU
of an air peak and the peak in question.
In runs on the A-600-B equipment, the point of initial emergence of the solvent peak was taken as reference. The conditions employed for the determination of relative retention times of the phenanthrenes shown in Table I are listrtl in the footnotes to this table.
Calculation of Relative Retention Times. The three examples below illustrate the use of the log factors and corrective terms in Table 11. 1,3,g-Trimet hgl-7-e t h ylphenant hrene on SE-30 column. From Table 11, the appropriate log factors and corrective terms are added: 0.179 (I-Me) 0.138 (3-Me) 0.1'70 (9-nfe) 0.272 (7-Et) - 0.020 (1,3-dialkyl) - 0.020 (l,9-dialkyl) - 0.020 (7,9dialkyl) = 0.699. Antilog of 0.699 = 5.00. The experimentally observed value is 5.24. 1,7,8,9-Tetramethylphenanthreneon QF-1-0065. From Table 11: 0.175 (Y-Me) 0.154 (7-Me) 0.17: (8-R;Ie) 0.169 (9-Me) 0.056 (7,8-di Me) 0.056 (8,9-di Me) - 0.027 (1,g-dialkyl) - 0.027 (7,9-dialkyl) - 0.013 (1,8dialkyl) = 0.718. Antilog 0.718 = 5.22. The experimentally observed value is 4.99. 1,2,7,8- Tetramethglphenanthrene on QF-1-0065 column. From Table 11, the appropriate log factors and corrective terms are added: 0.175 (1-Me) 0.154 (2-Me) 0.154 (7-RIe) 0.175 (&Me) 0.056 (1,2-di Me) 0.056 (7,8-di Me) - 0.013 (l,&dialkpl) 0.013 (2,7-dialkyl) = 0.744. T h e anti-
+
+
+
+
+
+
+
+
+
+
+ + +
log of 0.744 = 5.55. The experimrntally observed value is 5.46. DISCUSSION AN) RESULTS
Our study has now seen extended to iiiclude a much larger number of phenanthrenes than previously reported (9). This extension was made possible, in part, by employing ,ivery sensitive flame ionization detector which enabled us to study subrnilligram quantities of phenanthrenes. Full realization of the potentialities of the detector requires the use of a liquid phase of high thermal stability in order to minimize background noise caused by column bleed. T o this end, where the flame ionization detector w m utilized, DowCorning QF-1-0065 (:L fluorinated silicone) was employed a3 polar phase and G.E. SE-30 (a methyl silicone) as nonpolar phase (10). Table I lists, for each of the columns employed, the retention times of the various compounds relative to that of phenanthrene. -411 rtdative retention times reported represent the results of a t least two determinations. The values for the various runs on a given column have a maximum standard deviation of &2.0%. If, at least, two of the phenanthrenes of Table I are available, the relative retention times reported may be extrapolated, as shown in Figures 1 and 2, to accommodate determinations made under similar, but nclnidentical conditions. Figure 1 is 2, log-log plot of relative retentions times as determined on &foot (neopenty!gycol succinate) columns, in one case a I/g inch 0.d. column a t 225’ C. and in the other a ‘/4 inch 0.d. column a t 230’ C. Figure 2 is a log-log plot of relative retention times as determined a t 240’ C. on a 10 foot x inch 0.d. column containing SE-30 mothy1 silicone us. relative retention times determined a t 235’ C. on a 10 fool, X ‘/4 inch 0.d. column containing Ilow 11 methyl silicone as the liquid phase. Mixtures of phenanthrenes, such as would result from a typical dehydrogenation, can often Ee easily fractionated by gas liquid chromatography. I n our hands optimum results were obtained by the use of loads of less than 50 mg. on */4 inch 0.d. columns. Resolution generally increased as the load decreased. Preparatiyre runs were therefore made by repcatedly injecting small samples and collecting the various fractions. Corresponding fractions were then combined. [Instruments which perform these operations automatically (Aerograph Model 700 and F & M Model 77C) have recently been introduced.] Fractions isolated in this way may often be tentatively identified by determining their relative retention times under standard conditions on several differ:nt liquid phases.
If sufficient material is available, identification may be confirmed by spectral studies. A plot of log relative retention time of a homologous series of organic compounds us. carbon number gives a straight line ( 4 ) . Homologous series differing in amount or position of chain branching or unsaturation may be plotted against carbon number as a set of parallel lines (4). Alternatively, the lines may be combined by projecting the log relative retention times of one series of compounds onto the line determined by a second series. Points so projected will be displaced along the carbon-number axis by a distance equal in magnitude but opposite in direction to the distance which separated the intercepts of the original lines with this axis. The latter concept was used successfully in our previous paper (9), in which log relative retention times for several families of phenanthrenes were found to give linear plots against “degree of alkyl substitution”-a factor determined solely by the nature and extent of alkyl substitution. I n attempting to apply this method to the increased number of phenanthrenes included in the present study, we found that only those series of phenanthrenes in which the substituent being varied is located as position 2 ( 7 ) or 3 (6) would give linear plots against a common set of substituent constants. This deviation is probably caused mainly by steric interaction. The hindrance encountered by groups a t the 4 ( 5 ) position is obvious. Groups a t 1 ( 8 ) undergo a perinaphthalene-type interaction with substituents (H or alkyl) a t 10 (9) and vice versa. We therefore set out to test the more general hypothesis, that the contribution of a substituent to the retention time of a phenanthrene is a constant, the value of which is dependent both on the nature of the substituent and on the position of substitution (3). The log relative retention times of the methylphenanthrenes were factored to determine the contribution made by this substituent a t the various positions on the nucleus. The log relative retention times of the majority of the methylphenanthrenes could readily be fitted to the common sets of factors shown in Table 11. The exceptions fell into several easily recognized classes. Vicinal or l,10-(Sj9-) dimethylphenanthrenes have abnormally long retention times, but the deviation is constant for all cases studied. On a QF-1 column, 1,s- and 2,T-dimethyl substitution resulted in smaller than normal contributions, again by a constant amount. On either QF-1 or SE-30 columns dimethyl substitution a t positions 1 and 3 (6 and S), 1 and 9 (8 and lo), or 2 and 10 (7 and 9) requires substraction of a constant factor. From the limited
data available the log relative retention times of phenanthrenes containing substituents larger than methyl seem best to be approximated by the procedure described above, except that special correction factors, given in Table 11, must be employed for vicinal interactions involving these substituents. Not unexpectedly, the extreme hindrance (6) encountered by substituents in the 4 (5) position leads to irregular behavior. The values in Table I1 for 4 (5) substituents should therefore be used with caution. The use of the log factors and corrective terms appearing in Table I1 is illustrated in the Experimental Section by the calculation of relative retention times for three phenanthrenes. Columns 2 and 4 of Table I give the relative retention times of the phenanthrenes, on SE-30 and QF-1 as calculated from the factors in Table 11. With the exception of the 4-substituted phenanthrenes (for the reason mentioned above), the calculated relative retention times of all phenanthrenes fall within 6% of the measured values, thus demonstrating the validity of this general approach. These data should facilitate the rapid identification of small amounts of phenanthrenes obtained from the degradation of natural products. ACKNOWLEDGMENT
We express grateful appreciation to the investigators listed in Table I, who made available samples of substituted phenanthrenes. We thank Rajindra -4neja for obtaining the data for 1,2,7,8and 1,7,8,9-tetramethylphenanthrene on the SE-30 column. LITERATURE CITED
(1) Chang, T. L., Karr, C., Jr., Anal. Chiin. Acta 2 4 , 343 (1961). (2) Eglenton, G., Hamilton, R. J., Hodges,
R., RarJhael, R. A., Chem. Ind. (London) 1959,
p. 955.
(3) Evans, M. B., Smith, J. F., J . Chromatoa. 5 . 300 ~-~ i19611. 141 damen. A . T‘.. -l,iartin, A. J. P., Brit. \-r -Med. Bull. 10, ’170 (1954). (5) Newman, M. S., “Steric Effects in Organic Chemistry,” p. 476, Wiley, New York, 1956. (6)TOchiai, E., Okamoto, T., Sakai, S., Aatsume, M., Pharm. Bull. ( J a p a n ) 5 . 113 119471. ( 7 ) ‘Piozzi, F., Vita-Finzi, P., Atti. Accad. N a z . Lincei Rend. Classe Sci. Fis. Mat. S a t . , Ser. VIII, 2 9 , 549 (1960). (8) Plattner, P. -4.,Armstrong, E. C., “Sewer Methods of Preparative Organic Chemistry,” p. 21. Interscience. Xew York, 1948. (9) Solo, 8.J., Pelletier, S. W., Chem. Ind. (London) 1961, p. 1755. (10) VandenHeuvel, W. J. A . , Haahti, E. 0. A., Homing, E. C., J . Am. C h e m Sac. 83, 1513 (1961). Y
- I
-1
~
RECEIVEDfor review April 24, 1963. Accepted July 12, 1963. Investigation supported in part by Grant RG5807 (Cl-C4) and GM 10921-01 from the National Institutes of Health, U. S. Public Health Service. VOL. 35, NO. 1 1 , OCTOBER 1963
1587
