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KUWLEKAND L.
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STRAIT
1 COXTRIHUTIOV FROM 1 H B COLLECT O F PHARMACY AhD THE SPECTROGRAPHIC LABORATORY OF THE UKIVERSITY OF CAI IFORVIA, S h N
FRANCISCO~
The Ultraviolet Absorption Spectra of a-Phenylcarbonyl Compounds. 11' BY
EDR-ARD1,
=\I,PET\;,.'
11'. 11. KUXLERAND L. A. STRAIT
The spectra of 1,3diphenylpropanone-f has been previously reported4s5 but the curves have insutficient resolution and accuracy a t the shorter wave lengths. 1- Mesitylpropanone-2 has been previously prepared by several workers6 but its ultraviolet Libsorption spectrum has never been reported. The sample prepared by us shows the same phenylcarbonyl interaction that is found i n the Results unsubstituted phenyl series. A band (Fig. 2,i 'The spectra of l,l-diphenylbutaiione-1!m(f 1s present, X,,, 295 m p , emah 120, which may be 1 ,~bdiphenylpropanone-!?(Fig. 1) are very siniilar considered to be analogous to the sarne band in the longer wave length region, both having the found in the compounds previously discussed. 295 mp band with a molecular extinction of 200- The 295 m p band is distorted and lifted at shorter 2.30. There is a difference in the intensity of the wave lengths by the presence of the band A,, phenyl band as might be expected considering the 270 mu. This shorter wave length band is riature of the phenyl placement in the two coni- attributable to the mesityl grouping, and it is in pounds. It is noteworthy that the intensity of all respects norrnal when compared to other comthe 295 mp band in these two compounds is pounds containing; the iriesitylene nucleus. about half that found in :I,::-cliphenylbutailonc2.3 The fine structure of these three u-diphenyl ketones has ail the major inflections a t alI most identical wave lengths, and in addition the detail is qualitatively similar to that found in the 295 mp band of the nionophenyl ketones. In Part I of this series$ we have considered the ultraviolet absorption spectra of some a-phenylcarbonyl compounds, pointing out that a band at 295 nip with a molecular extinction of more than tenfold that of a simple aliphatic carbonyl COIIIpound is characteristic of the cu-I'henylcarbonyl grouping, Ke have further extended these qtudies and are reporting thein herc
1
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303 MI-
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26
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enables one t o evaluate roughly the interaction energy between the cas-bony1 group and the aphenyl group. In paper I i t was pointed out that if we place a group l3 in the compound A
0
tallizations from ligroin Thc iueltmg point of the final product was 59-60' (lit. BCttil 1 . The semicarbdzone gaye white needles from alcohol, i n . p, 196- 197;". The ketone h : ~ R l characteristic caramellike odor. 2-Phenylcyclohexanone. -This ketone was prepared by two methods to ensure spectroscopic purity by comparison. The first method was that of Price and Karabinoslo using now Chemical Co. technical (70y0)2-phenylcyclohexanol. This was redistilled through a 30" Widmer column and the fraction boiling a t 146-147" at 12 mm. was collected; yield of ketone on oxidation of the purified 2-phenylcyclohexaiol, 297;. The boiling point of the product was 1.18152" at 15 mni. Recrvytallization three times from uetroleuni ether gave a fi&l m. p . of 51.5-5-1"; seinicarbdone in. p 189-190" (lit. 189-190, 193'). The alternate preparation was that of Sewmnn and Parbinan" by the Grignard reaction on 2-chlorocycloheuanone; 20 g. of ketone, b. p . 133-136" a t 4 mm., m. p. 43-50'', was recovered from 58 g. of 2-chlorocyelohexanone. Two recrystallizations from petroleum ether gave a h a 1 product n,hich was pure white, with a citron-like odor and m. p. 59 . The two products were of identical spectroicopic purity __-- __ ( 8 ) Walton, Ofner and Thorp, J Chem Soc , 084 (19491 (9) Vogel "Practical Organtc Chemlstry," 1,ongm.rni < ? r t < n A
Materials Hexane.--Enstni,m Roddk Co. practical grade hexaiie (from petroleum) b. p . 6 2 4 7 ' wa> used. Batches s%ere Cn selected t h,it g,tvc trctii-ini\40ii \-,iluc\ :rg,iinit :tir of 9.5": or 1,ctt
