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COMMUNICATIONS
Synthesis of an Isomer of Umbellulone
Sir: I n view of current interest in the chemical and spectroscopic properties of cyclopropane compounds we wish to report' that we have confirmed the structure2 of umbellulone [I, R1 = CH3, 11, = CH(CH3),] by the synthesis of an isomer [I, Rl = CH(CH,),, R2 = CH3] which contains the 13.1.0.1-bicyclohexenone chromophoric system (I) and has an ultraviolet absorption spectrum A,[X:: 216 mp ( e 7800), 262 (3200), sh. 320 (184)] practically identical with the anomalous absorption 220 spectrum reported3 for umbellulone [AX$:, (5900), 265 (3290), sh. 330 (2lO)l.
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I-isobutyrylbic~yclo[X.I.0.]4-hexenon-6 (I, 13' = CH(CH8),, It2 = CH,), [b.p. 54"at 1 mm.; n$ 1.4853; C, 79.48, H,9.57: X A E z 5.90 p (C==O), 6.28, (C=C, conj.)]. DEPARTMENT OF CHEMISTRY AND HOWARI) E. SMITH CHEMICAL ENGIKEERIKG RICHARD H. EASTMAN STANFORD UNIVERSITY
STAs FO RI), CALIFORK IA Received May 21, 1956
The Infrared Spectra of Aromatic Organoalkali Compounds
Si?:
Kross and Fassel reported recently that a plot of absorption frequencies in the region 1045-1 18.5 cm - l uersus the electronegativity squared of the substituent element yielded linear energy relationships for a series of compounds of the type (phenyl),M, R? where n is the valence of the substituent M.' They studied three to five compounds in each I periodic group from IV B through VI1 B. In each group they obtained linear relationships and the Diazomethyl isopropyl ketone reacted with lines for all four groups extrapolated to a commoii methyl methacrylate t o give after thermal decom- point a t 984 em.-'. These workers suggest that the position of the intermediate pyrazoline, l-carbo- substituent-sensitive vibration being used arises methoxy-2-isobutyryl-1-methylcyclopropane (11) from a C-H planar mode. (C, 65.27; H, 8.82) in 35% yield. I1 was hydrolyzed Similar linear energy relationships might be prewith alkali t o a syrupy mixture of cis and trans- sumed t o exist for aromatic organometallic com2-isobutyryl-1-methyl-1-cyclopropane carboxylic pounds in groups I through 111. A logical starting acids from which the crystalline trans isomer I11 point is group I, but no infrared spectra of organo(m.p. 56-57', C, 63.83, H, 7.84) wasisolated. After alkali compounds have been reported. Accordingly , structure proof by oxidation t o the known* trans- spectra were run on phenyl-lithium, -sodium, and l-methyl-lJ2~cyclopropanedicarboxylicacid, I11 -potassium. Phenyllithium mas prepared from was converted via reaction of its acid chloride (C, bromobenzene, while the sodium and potassium 57.94, H, 7.30) with the cadmium methyl Grignard compounds were prepared by metalation of benzene reagent5 t o 1-acetyl-2-isobutyryl-1-methylcyclo- with amyl-sodium and -potassium respectively. propane (b.p. 120-122' at 2 mm. ng 1.4670, C, Solvent-fice Kujol mulls were prepared and spec71.42, H, 9.80) which underwent aldol cyclization tra determined on a Perkin-Elmer (model 21) inon treatment with dilute base to yield l-methyl- frared spectrophotometer. Many bands were obtained for each compound, some of which could be identified as characteristic of a monosubstituted benzene. Phenylsodium, for example, gave medium intensity bands at 1590 and 3030 cm.-l, characteristic of an aromatic structure. Strong bands ap(1) Reported in part at the 125th meeting of the American peared at 705 and 671 cm.-' and weak bands a t Chemical Society in Dallas, Texas, March, 1956. 1970, 1880, 1850, and 1805 cm.-l, all of which are (2) F. W.Semmler, Ber., 40,5017 (1907). ( 3 ) A. E. Gillam and T. F. West, J . Chem. SOC.,98 (1945); characteristic of a monosubstituted benzene.?
bo
R. H. Eastman, J. A m . Chem.Sm., 7 6 , 4115 (1954). (1) R. D. Iiross :md V, .4.Fass~l,.I. A m . Chem. SOC.,77, (4) C. K.Ingoid, J . Chem. Soc., 398 (1925). (5) J. Cason, J. A m . Chem. Soc., 68, 2078 (1946); R. H. 5558 (1955). (2) I,. J. Bellamy, The Infrared Spectra of Complex MoleEastman and S. K. Freeman, J. Am,. Chem. SOC.77, 6642 cules, John Wiley and Sons, Inc., New York, N . Y.,1954. (1955).
