Feb., 1944
SPECTROGRAPHY OF A
[CONTRIBUTION FROM THE CHEMICAL
NEWHYDROCARBON
LABORATORIES OF HARVARD UNIVERSITY
185
AND QUEEN’S
UNIVBRSITY]
The Spectrographic Characterization of a Hydrocarbon Synthesized by Bergmann
and Eschinazi
BY R. NORMAN JONES Selenium dehydrogenation of the cyclized condensation product of cyclohexenylcycloheone with a-naphthylmagnesium bromide yields a product which Bergmann and Eschinazi’ believed to possess either structure IV or V as shown in their article. The ultraviolet absorption spectrum provides a method of distinguishing between these two structures, since IV‘ is an alicyclic derivative of
A
3,4-benzphenanthrene and (V)l is an alicyclic derivative of chrysene. It is known that alicyclic rings do not alter significantly the spectrum characteristic of the polynuclear aromatic hydrocarbon to which they are attached.2 The spectrum of (IV)’ should resemble closely that of 3,4-benzphenanthrene, and the spectrum of (V) should be similar to the spectrum of chrysene. The spectrum of Bergmann and Eschinazi’s hydrocarbon is compared with the spectra of chrysenea and 3,4-ben~phenanthrene~ in Fig. 1; but the resemblance to either of these spectra is so slight as to cast considerable doubt on the close relation of the compound to either hydrocarbon. In Fig. 2 the spectrum of Bergmann and Eschinazi’s hydrocarbon is compared with the spectrum of 3,4-benzfluorene4 (A) which it resembles closely in the region from 2200 to 3600 A. The low intensity structure between 3800 and 4600 A., not observed in the spectrum of 3,4-benzfluorene, may be due to a trace of impurity. Assuming an intensity of log Emolar = 4.0-4.5 for a hy othetic d component responsible for the 4360 maximum, t h i s would indicate a concentration of about 0.1% of impurity. Structure in this region of the spectrum was observed in early determinations of the spectrum of fluorene, but was later shown to be due to impurities.6 It is also possible that corresponding low intensity structure might be present in the spectrum of 3,4-benzfluorene, but was not recorded by Mayneord and Roe,’ whose measurements did not extend below log
1
(1) BeWmann and Eschinazi, Tms JOURNAL, 66, 183 (1944). With the Uceptlon of structure (A), refuence should be made to tM. paper for structural formulas discussed in the current article. (2) Jon-, Chem. Ra.,SI, 1 (1943). (3) Redrawn from the data of Mayneord and Roe, Proc. Rw. Soc. (London), A161, 299 (1935). (4) Redrawn from the data of Mayneord and Roc. ibid., AlM, 634 (1937). (5) Aakew, 1.Chem. SOL 512 (1936)
0.8
I
4.8
4.0
l
l
l
l
l
l
l
l
l
l
-
-
d0 a 3.2 w M 3 2.4 -
1.6
-
0.8
I 2400
l
l
l
l
l
i
l
l
l
l
2800 3200 3600 4000 4400 Wave length, A. Fig. 2 ., Absorption spectrum of Bergmann and Eschinazi’s hydrocarbon ; - - - - - -, spectrum of 3,4benzfluorene.
A. POLGAR AND L. ZECHMEISTER
186
benzfluorene. This is unusual, but a Slmi1a.r deet has been recorded by Bachmann and CarmackJ6 who compared the spectra of 3,4-benzpyrene and its 4',bdimethylene derivative. The formulation of Bergmann and Eschinazi's hydrocarbon as a derivative of 3,4-benz%uorene requires the postulation of a five-membered ring closure, the product being 9,9-spirocydohexanyl3,4-benzfluoreneI (VI)l in their article. The presence of the spirane ring should not affect the spectrum,' and the failure of this compound to hydrogenate further' also supports this formulation. The spectrum of the quinone derived from (VI)' by oxidation, which has a probable structure (VII),l is recorded in Fig. 3; but in the absence of comparative data, this is of no value for the further characterization of the ring system.
Vol. 66
TABLE I POSITIONAND INTENSITY OF ABSOJLPTION MAXIMA Wave length, b. Iotensitr (log ~ r n o l n r ) (a) Hydrocarbon (VI)* (solvent ethanol) 3150 4.45 3250 4.43 3395 4.55 3845 1.38 4105 1.61 4360 1.69 (b) Quinone (VII)' (solvent ethanol) 2470 4.28 2680 4.32 3330 3.94 4600 3.49
In Table I data for the position and intensity of the maxima of the spectra of compounds (VI)' and (VII)' are recorded. The spectrographic
I
r-
3.11 I 2600 Fig. 3.--,
3400 4200 5000 Wave length, A. Absorption spectrum of quinone (probably VIP).
methods employed have been reported previously. * Acknowledgment.-The author wishes to express his thanks to Professor L. F. Fieser, of Harvard University, in whose laboratory the spectra were determined, and to acknowledge the financial support of The International Cancer Research Foundation.
summary Comparison of the ultraviolet absorption spectrum of a hydrocarbon synthesized recently by Bergmann and Eschinazi, with the spectra of rhrysene, 3,4benzphenanthrene and 3,4-benzfluorene suggests that the new hydrocarbon is 9,9-spirocyclohexanyl-3,4-ben~uorene.
(6) Bashmano and Carmack, Tars JOUBNAL, 62, 1685 (1941). (8) Jones. Tms Jonnarm,, 6S, 148 (1940). (7) Compare the spectra of ' I s ~ p d r o p h ~ l y 1 - 7 ~ i ~ ~ I ~ n RECEIVED SEPTEMBER 10. 1943 KINGSTON,CANADA tam? sod oaphthaleoe, in reference 5.
[CONTRIBUTION FROM
THE
GATESAND CRELLIN LABOIUTORIES OF CHEMISTRY, CALIFORNIA INSTITUTE OF TBCHNOLOGY No.9391
A Spectroscopic Study in the Stereoisomeric Capsanthin Set. Configuration BY A. POLGARAND L.ZSCHMEI~TER
&-Peak Effect and
* ed for each stereoisoRecent experiments with some carotenoid the &-peak can bedetermrn hydrocarbons and alcohols have shown that the mer.'.*#* This procedure has been used recently bending of the molecule by trans + cis rearrange- to assign tentative configurations to the main ments which modify the entire extinction curve observed members of the stereoisomeric sets of produces a particularly characteristic change in a a-carotene, fl-carotene, lycopene and lutein.*.a certain ultraviolet region of the spectrum.' In order to provide data for compounds of This change which results in a new maximum, another type a carotenoid ketone, capsanthin, the "cis-peak," between 320 and 380 mp has CmH&, which is the main pigment of the red recently been given a theoretical interpretation.* pepper (CapsiczCmalpnuurn) has been investigated. After a chromatographic separation of the Capsanthin was one of the first &-carotenoids main stereoisomers which are present in a mix- in which stereochemical effects in the form of ture formed by iodine catalysis, the height of spontaneous isomerization were observed by Cholnoky and OLE of the authors.* This was (I) L.Zechmuster and A. Polgat. THISJOWBNAL, 86, 1522 (1943).
(a) L. zshmeuta.A. L. LcRonn. W.A. Schracdu,
and I,. Pauling. iMd.. 66, 1040 (1943)
A. Pol&
(3) L. Zcfhmdster and A. Pol&, ibid., 66, 137 (19433). (4) L. Zcchmehter nod L. Cholnoky. Aim.. uB.391 (1W).
