Ethyl Azodicarboxylate with Conjugated Dienes. II 3177 chlorobenzene was refluxed (124°) under nitrogen for 12 hr. Upon cooling, 17.5 g. of fine, snow white crystals of meso-1,2-dichlorostilbene28 separated and were isolated (m.p. [193][194]. Upon evaporation of the solution to one half its original volume and chilling, a further 8.5 g. of this compound were obtained. The remaining solution was evaporated to dryness and the residue was recrystallized from petroleum ether to yield 4.0 g. of dl-l ,2-dichlorostilbene28 (m.p. 90-91°).Chlorination of Cumene.-A solution of cumene (240 g., 2 moles) and PC15 (208 g., 1 mole) was stirred and refluxed (110°) under nitrogen for 14 hr. Hydrogen chloride was rapidly evolved during this period. After washing with water and NaHCOg solution, the clear yellow solution which was obtained as distilled through a short packed column. There was obtained 44 g. (28.5%) of phenyldimethylcarbinyl chloride, b.p. 95-96°(15 mm.). N.m.r. showed a sharp singlet at 8.22; ratio of aliphatic protons to aromatic protons 6:5. There was also obtained 95 g. of a substance boiling mainly at 120-135°( 15 mm.). This colorless liquid showed greatly diminished methyl peaks in its n.m.r. and infrared spectra as well as evidence in the former for -CH2Cl groups and small amounts of vinyl pro-tons. It was not investigated further. These results were essentially reproducible. From the relative retention times in the v.p.c. analysis it was estimated that a mixture of diand tri-chlorinated products had been formed.Catalyzed Chlorination of Cyclohexane.-A mixture of cyclohexane (84 g., 1 mole) and PC15 (70 g., 0.33 mole) in 200 cc. of o-dichlorobenzene was refluxed (88°) under nitrogen for 7 hr. Small quantities of benzoyl peroxide were added periodically during this time and HC1 was evolved. After cooling, the reaction mixture (which was a light yellow color at this point.) was poured onto ice water. The organic layer was separated, washed consecutively with water and 5% NaHCOg solution, and then dried over anhydrous CaCl2. Analysis by v.p.c. indicated a 70.2% yield of cyclohexyl chloride had been formed (based on PCls).Acknowledgment.-We wish to thank Mr. Carl Lindemann for the gas chromatographic analyses and Mr. Paul Kaufman who helped with some of the experimental work.

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THE STRUCTURE OF ELAIOMYCIN, A TUBERCULO-STATIC ANTIBIOTIC Sir: Structure I is proposed for the antibiotic Elaiomycin.1 This antibiotic is chemically unique, (1) T. H. Haskell, Q. Bartz, et al. [Antibiotics and Chemotherapy, 4, 141, 338 (1954) ] described the isolation, purification, spectra, chemical characterization, and biologic studies of Elaiomycin [4-methoxy-3-(1octenyl-2VO.V-azoxy)-2-butanol], since to our knowledge the chromophore repre-

D-th~eO-CONFIGCRATION O F ELAIOMYCIN 1435times with ethyl acetate. The remaining aqueous portion then was filtered to remove the brown humin and diluted to a known volume with 1 N HC1. The optical density of the aqueous portion was determined a t 390 mp and the amount of 6-DNP-lysine calculated by comparison with a standard curve.36 In some cases, the method of Porter3E and that of Levy16 were used. The ether-ethyl acetate solution was evaporated to dryness in a current of warm air. The residue was taken up in a small amount of water-saturated chloroform. This solution then was placed on a silica gel column as described by Porter3B and the DNP-valine separated from dinitrophenol, dinitroaniline and DNP-peptides. After separation was complete, the column was extruded, and the DKPderivatives eluted with acetone, evaporated to dryness, dissolved in 1% NaHC03 solution and the optical density determined a t 350 mr. The moles of DXP-residue were determined using 17,000 as the molar extinction coefficient for DNP-valine. The extinction coefficient for the DNPpeptide was also assumed to be 17,000.34The results of recovery experiments of DL-valine when hydrolyzed in the presence of DNP-chymotrypsin and DNP-lysozyme are recorded in Table 111. -4pproximately 1 mg. of DNP-valine and 20 mg. of DNP-protein together