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these four products are formed at -75’ in the ration 10 :25 : 25 : 40 and at 15’ in the ratio 11 : 26 : 26: 37. Here again one product, l-niethylcyclohexene, appears to be formed in amount differing slightly from the statistical, but the estimated error of 1070is too large to justify further comment a t this time. Finally diazomethane reacts with cyclopentane to give methylcyclopentane unaccompanied (less than 0. 1y0)by cyclohexane. Within much increased limits, one concludes that methylene does not react (9) W. D . Paist, E . R. Blout, F. C . Uhle and R . C. Elderfield, J . with the carbon-carbon bond. O v g . Chem., 6, 273 (1911). Within a few per cent. it is clear that methylene MEDICITALCHEMICAL RESEARCH SECTIOK fails to distinguish between different types of RESEARCH DIVISIOS AMERICANCYASAMID COMPASV ~ ‘ I L L I A M S. ALLEX carbon-hydrogen bonds, reacting a t random with LEDERLE LABORATORIES SEYMOUR BERNSTEIN l o ,2’ and 3’ aliphatic C-H bonds as well as with PEARL RIVER,NEWPORK “allylic” and “vinyl” types. Even more surprisRECEIVED . ~ P R I L 6, 1956 ing is the fact that the reaction cross-section of the double bond is only about three times that of a INDISCRIMINATE REACTION OF METHYLENE hydrogen atom. One might reasonably have exWITH THE CARBON-HYDROGEN BOND pected an overwhelming preference similar to that Sir: shown by dichlorocarbene. Methylene must be PIIethyle ne shows essentially no discriminatory classed as the most indiscriminate reagent known power in its reaction with the carbon-hydrogen in organic chemistry. bonds’ in the saturated hydrocarbons, n-pentane The experiments were carried out in the usual and 2,3-dimethylbutane and in the olefin, cyclo- way by irradiating very dilute solutions of diazohexene. When diazomethane is irradiated with methane in the hydrocarbon with sun-lamps, rethese hydrocarbons either a t -75’ or at 15”, the moving most of the solvent by fractional distilladistribution of products resulting from insertion tion in a 50-plate column and analyzing the product of the carbene into a carbon-hydrogen bond is by gas-liquid partition chromatography using a very close to statistical. For example, diazo- Perkin-Elmer Model 154 Vapor Fractometer and methane may react with n-pentane a t carbon atoms by infrared spectroscopy. I n all cases but one, 1, 2 or 3 to give n-hexane, 2-methylpentane and 3- samples of pure product were isolated from the methylpentane in the statistical ratio 6 : 4 : 2 or Fractometer and identified by comparing their 50: 33.3 : 16.7, respectively; in fact, these three infrared spectra with those of authentic samples products are formed a t -75’ in the ratio 48:35: 17; (neat, 0.1-mm. cell). In the cyclohexene reaction and a t 15’ in the ratio 49:34:17. where the Fractometer mould not resolve 3- and 42,3-Dimethylbutane which contains primary and methylcyclohexene but easily separated this mixtertiary hydrogen in the ratio of 12 : 2 or e5.7 : 14.3 ture from the other components, analysis was made reacts with diazomethane to give 2J-dimethylinfrared spectroscopically comparing with known pentane and 2,2,3-trimethylbutane in the ratio mixtures of the authentic olefins. 53:17. It is possible that the small difference (2) W. v a n E . Doering and A . K . Hoffmann, THISJ O U R N A L , 1 6 , between the statistical and actual values lies out- 6162 (1954). (3) Sterling Chemistry Laboratory, Yale University, Kew Haven, side the experimental error but higher resolution in the form of considerably refined techniques Connecticut. W , \‘ON E. DOERINC3 would be required to decide. R. G. BUTTERY HICKRILL CHEMICAL I n cyclohexene there are three types of carbonR. G. LAUCHLIN RESEARCH FOUNDATIOS K. CHAUDHURI hydrogen bonds of widely differing chemical char- KATOSAH,NEWYORK RECEIVED J U N E 4, 1956 acteristics : the “vinyl” hydrogen atoms a t carbon atoms 1 and 2 , the “allylic” hydrogens a t Cs and Ce and the “aliphatic” hydrogens a t C4 and Cg. SYNTHESIS OF APOGOSSYPOL HEXAMETHYL ETHER Reaction with methylene can occur in principle a t each type of carbon-hydrogen bond to give 1- Sir: methylcyclohexene, 3-niethylcyclohexene and 4hpogossypol hexamethyl ether, the primary degmethylcyclohexene, respectively, in the statistical radation product of gossypol (I),has been formulated ratio of 2 : 4 : 4 . Reaction can also occur by addi- as 2,2’-bi-5-isopropyl-1,6,7-trimethoxy - 3 - methtion to the double bond to give norcarane. I n fact, ylnaphthyl (11) by Adamsl as a result of his extensive and thorough studies. The Adams structures (1) T h e photochemical decomposition of diazomethane was first in\.estigated by H. Meerwein, H. Rathjen and H . Werner, B e y . , 75, however, have been criticized recently by three I O I O (1942), in ether where ethyl n-propyl and ethyl isopropyl ether separate groups of i n ~ e s t i g a t o r s . ~The ~ ~ , ~present were formed. Although t h e latter product appears t o be formed b y H , 7.96), positive legal t e ~ t . ~Treatment ,~ of I with acetic anhydride-pyridine a t room temperature yielded only starting material. The compound formed a mono-2,4-dinitrophenylhydrazone at C-3, m,p, 2560 d , , chloroform-sba.&IC. 257 ( E 17,300) and 357-388 mp (E 29,000) (Anal. Calcd. for C27H32N408:C, 59.99; H , 5.97; N, 10.37. Found: C, 59.71; H, 6.15; N, 10.25). il detailed report of this work will be forthcoming in this JOURKAL.
direct reaction of a carbon-hydrogen bond, t h e presence of t h e oxygen a t o m and the possibility i t affords for initial “ylid” formation [see R . Huisgen, Angew. Chenz., 6 1 , 439 (195513 makes the mechanism ambiguous. T h e direct reaction of carbethoxy carbene with saturated hydrocarbons has been reported b y W. van E . Doering and L. H. Knox, 119th Meeting of t h e American Chemical Society, Boston, >lass., April 2, 1951 “Abstracts of Papers,’’ p . 21.1, and THISJ O U R N A L . in press.
(1) R. Adams, R. C. Morris, T. A . Geissman, D . J . Butterbaugh and E. C. Kirkpatrick, THISJOURNAL, 60, 2193 (1938). (2) D . A. Shirley and W. L. Dean, ibid., 11, 6077 (1955). (3) R . T. O’Connor, P Haar, E. F. DuPre, L. E. Brown and C . H. Pominski, ibid.,1 6 , 2368 (1954). (4) C. H. Boatner, “Pigments of Cottonseed and Cottonseed Products,” Edited b y A. E . Bailey, Interscience Publishers, Inc., Xew York, N. Y., 1948, Chap. V I , pp, 215-262.
