2,4,6-Trinitrostyrene

Downloaded by HENKEL KGAA on August 18, 2009 Published on April 1, 1950 on http://pubs.acs.org | doi: 10.1021/ja01160a120 1822 RICHARD WILEYAND LYELL BEHR H. C. only by redetermining the optical properties of crystals obtained from the original source. Striiverg obtained his material from the lichens Zeora sordida and Usnea barbata. Kappen‘O obtained I-usnic acid from Usnea barbata and the d-usnic acid from Usnea longissima. A lichen collected by one of us (F.T.J.) and identified by the University of California Botany Department as Usnea californica Herre has yielded crystals of usnic acid“ having optical and crystallographic properties identical with those of the material obtained from Ramalina reticulatu reported above. This evidence makes it practically certain that Kappen’s values for the refractive indices of usnic acid are in error. His method for determining the indices is not clearly stated but the implication is that i t was a goniometric method utilizing the usnic acid crystal as a prism. The sample from Usnea californica was too small to test for optical rotation but .the material is probably the dextrorotatory isomer. Abderhaldenll lists only the d isomer from any of the Usneas; consequently Kappen must have obtained his I-usnic acid from a lichen mistakenly identified as Usnea barbata. Acknowledgments.-We wish to express our thanks to Merle Ballantyne for taking the X-ray (11) E. Abderhalden, “Biochemisches Handlexikon,” Vol. 7, J. Springer, Berlin, 1912, p. 116. [CONTRIBUTION FROM THE \‘ENABLE CHEMICAL Vol. 72 diffraction photographs, to Oliver Emerson for determining the molecular weight, and to N. Floy Bracelin for help in the preparation of Fig. 2 and for assistance in finding a source of Usnea califomica. We also thank Phyllis Gardner, herbarium botanist of the University of California, and C. W. Dodge of Washington University and the Missouri Botanical Garden for their assistance in finding and identifying the Usnea californica Herre. Summary The optical properties of usnic acid isolated from the lichens Ramalina reticulata, Parmelia moliuscula, and Usnea californica Herre have been determined. The crystals obtained from chloroform solution are orthorhombic with indices a = 1.611, ,B = 1.710, and y = 1.772. These values differ markedly from those originally reported for usnic acid. X-Ray diffraction photographs of these crystals give a = 19.10 A. parallel to p, b = 20.39 A. parallel to y, and c = 8.09 A. parallel to a. The space group is probably D j - P212121 but may be D$ - P21212, and the density is 1.46 g./cc. There are two crystallographically unrelated sets of four molecules each in the unit cell. ALBANY, CALIFORNIA LABORATORY OF THE RECEIVED SEPTEMBER1949 3, UNIVERSITV OF I\;ORTH CAROLINA] 2,4,6-Trinitrostyr ene BY RICHARD WILEY~ LYELL BEHR H. AND C. Polynitrostyrenes have not been previously reported in the literature. It was felt that i t would be of interest to attempt preparation of such compounds, and to observe their polymerizability, in view of recent reports of the successful polymerization of m-nitrostyrene3 and p-nitrostyrene, and of the fact that 1,3,5-trinitrobenzene is an efficient inhibitor of vinyl polymerization.6 In this paper, we wish t o report a successful synthesis of 2,4,6-trinitrostyrene and some attempts to polymerize it. A method which has been successful in the synthesis of many substituted styrenes consists in the decarboxylation of the corresponding cinnamic acid. Attempts to prepare 2,4,6-trinitrocinnamic acid for use in this reaction have been unsuccessful in these laboratories. We have, however, obtained 2,4,6-trinitrostyrene by the series of reac(1) Work done under a contract with the Bureau of Ordnance, Department of the Navy. (2) Present address: University of Louisville, Louisville, Rcn- tuckr. (3) Wilej and Smith, J . Polymer Sci., 3, 444 (1948). (4) Strarshurp, Gregg and Walling, THIS JOURNAL, 69, 2141 (1947). (5) Frank and Adorns, ibid., 68, 908 (1946). tions diagrammed below. Mannich condensations with 2,4,6-trinitrotoluene have been previously carried out using the free amine and formaldehyde solution in the presence of alkali,6 but our experience was that this technique produced undesirable by-products (probably due to the action of the alkali) which were difficult to remove and which tended to make the product less stable. We therefore carried out the condensation in absolute alcohol, using the amine hydrochloride and paraformaldehyde. The hydrochloride (I) thus obtained was converted, without isolation, into the free base and thence to the methiodide (11). The over-all yields in this reaction varied from 15-40y0 of the theory. It should be noted that the free amine of the hydrochloride (I) was unstable, particularly in alkaline medium. Use of sodium carbonate, rather than the calcium salt, to free the base from the hydrochloride often resulted in profound decomposition. The methiodide (11)is also somewhat unstable on standing. Conversion to the styrene was carried out in an aqueous methanol solution, using silver oxide. Yields up to 65% of theoretical were obtained. Decom(6) Bruson and Butler, ibid., 68, 2348 (1946). April, 1950 1823 2,4,6-TRINITROSTYRENE TABLE I 7 Yield, % Compound, -ethane methiodide Mi p . , C. Formula Carbon Calcd. Found Analyses, % Hydrogen Calcd. Found Nitrogen Calcd. Found l-Dimethylamino-2-(2,4,6-trinitrophenyl)-18 142-144 d. Cl1Hl5IN406 31.00 30.09 3 54 3.60 13.15 14.04 1-Diethylamino-2-(2,4-dinitrophenyl) 24 133-135 d. C13HZoIS304 10.27 10.72 l-Dimethylamino-2-(2,4-dinitrophenyl)- 20 137-139 d. C11HlsIN30, 11.02 10 83 - position of the quaternary hydroxide occurred Anal. Calcd. for C13H1JX4O6: C, 34.33; H, 1.22; temperature.The styrene 1327.72; N, 12.34. Found: c , 34.08; H, 4.44; IJ27.58; spontaneous~y at N, 12.50. was Obtained from the Of Recrystallization of the methiodide was carried out as the methiodide. rapidly as possible and using small quantities, because of Downloaded by HENKEL KGAA on August 18, 2009 Published on April 1, 1950 on http://pubs.acs.org | doi: 10.1021/ja01160a120 the danger of decom- long dark needles of a compound whose structure has not been deterJCaCO., then CHII mined. ,NO2 Anal. Found: C , AgzO 23.00; H, 3.48; N , OJ-Q-CH=CH: O ~ N - ~ C H z C H zH(CHzCH3)z (11) 8.10; I, 50.21. h , I 2.4.6-Trinitrostvrene. 'NO2 -To.a solution of4.6 g. 1of 1-diethylamino-2- (2,(111) 4,6-trinitrophenyl) -ethAttempts to polymerize 2,4,6-trinitrostyrene ane methiodide in 100 cc. of methanol, there was added 100 cc. stirred while in bulk with benzoyl peroxide, in solution with 5.0 g. ofof water. The mixture was vigorously immediately silver oxide was added. The solution benzoyl peroxide and with boron trifluoride, and became blood-red; it was stirred for one minute and then in emulsion with persulfate were unsuccessful. filtered with suction through a layer of infusorial earth. Copolymerizations with maleic anhydride in The filter cake was washed with water until the washings benzene solution, styrene in bulk and in emulsion, were nearly colorless. The combined filtrate and washings were allowed to stand a t room temperature for twelve and isoprene in emulsion also failed. Evidence hours. The precipitated 2,4,6-trinitrostyrene was rewas accumulated, in fact, that the trinitrostyrene moved by filtration, washed with water and air dried. I t was recrystallized from a benzene-petroleum ether mixinhibits styrene polymerizations. ture, which I n an attempt to prepare 2,4-dinitrostyrene amounted to removed a red, tarry material. The yield 1.2 g. ($9yo of theoretical) of yellow flakes or analogously, decomposition of the methiodide rhombs, m. p . 64-65 . gave an apparently non-crystalline solid with Anal. Calcd. for CsHbN306: C, 40.13; H , 2.18; S , approximately the proper composition. How- 17.57. Found: C40.09; H,2.44; N, 17.55. Data for other methiodides, which were prepared simiever, i t decomposed without melting above 200' and was insoluble in the common organic sol- larly, are given in Table I. grams of l-diethylamino-22 ,4-Dinitrostyrene.-Two vents. It was soluble in dimethylformamide, (2,4-dinitrophenyl) -ethane methiodide was dissolved in a but did not give a continuous film upon evapora- mixture of 30 cc. of methanol and 20 cc. of water. The tion of the solvent. The Mannich condensation mixture was mechanically stirred and 3 g. of silver oxide added. The solution turned blue-violet. Vigorous stirwith o-nitrotoluene was unsuccessful. ring was continued for two minutes and then the mixture Experimental Part was filtered with suction through infusorial earth. The filtrate was allowed to stand twelve hours (it clouded 1-Diethylamino-2- (2,4,6-trinitrophenyI) -ethane Methiodide.-A mixture of 36.2 g. (0.16 mole) of 2,4,6-tri- almost immediately) and was then filtered. The material nitrotoluene, 22.0 g. (0.20 mole) of diethylamine hydro- thus obtained was a bluish powder, which was insoluble chloride and 12.0 g. (0.40 mole) of paraformaldehyde in in the common solvents, but soluble in dimethylformamide. 200 cc. of absolute alcohol was mechanically stirred and When this solution was allowed to evaporate on a glass heated a t reflux for twenty-four hours. During this time, plate, the resulting residue was discontinuous. The two further additions of 5 g. of paraformaldehyde were material showed no crystalline form under the microscope. The yield obtained was 0.9 g. made. The flask was then cooled in ice, and 500 cc. of Anal. Calcd. for CsH&z04: C, 49.48; H , 3.12; K , water with 10 cc. of concentrated hydrochloric acid added. The oil which formed was removed by extraction with 14.44. Found: C,49.15; H,3.68; N, 14.27. ether and calcium carbonate was added cautiously to the Attempts to Polymerize Trinitrostyrene. (a) Bulk,yellow aqueous solution until an excess remained undis- Mixtures of styrene and trinitrostyrene of the following solved. The resulting mixture was extracted ten times percentages of trinitrostyrene were allowed to stand in an with 200-cc. portions of ether, the ether extracts dried oven a t 62': 100, 50, 25, 12.5, 5 , 0%. Benzoyl peroxide over anhydrous calcium chloride and evaporated under re(0.1% by weight of monomers) was used as initiator. The duced pressure without heating. The amine was not fur- styrene tube showed evidences of polymerization after ther purified. An equal weight of methyl iodide was three hours; the others showed no increase in viscosity added, and after an induction period sometimes amounting in one week. Under the same conditions 0.05% trinitroto forty minutes, orange crystals began to form. Cooling styrene was found to inhibit styrene polymerization for - was occasionally necessary after the reaction started. three days. The mixture was allowed to stand for eight hours; the (b) Solution.-A mixture of 1 g. of trinitrostyrene and solid was removed by filtration and recrystallized from 15 cc. of ethyl chloride was stirred a t -50", while gaseous methanol-ethanol. The yield of orange crystals, m. p. boron trifluoride was passed into the mixture for one and 125-126' dec., was22.3 g. or 30y0of the theoretical. one-half hours. The ethyl chloride was allowed to evap- ROBERT FRANK, L. GEORGE CLARK R. AND 1824 Downloaded by HENKEL KGAA on August 18, 2009 Published on April 1, 1950 on http://pubs.acs.org | doi: 10.1021/ja01160a120 orate a t room temperature. A small amount of oil remained and, after purification, 0.86 g. of trinitrostyrene was recovered. Heating a solution of 1 g. of trinitrostyrene in 10 cc. of benzene with 0.3% benzoyl peroxide under reflux for two days produced darkening but no polymer. (c) Emulsion.-The following trinitrostyrene-styrene emulsions in water were heated in a bath a t 50” which was equipped for rotating the mixtures (figures are per cent. of trinitrostyrene based on total monomer , composition) : 100, 20, 0.4, 0%. Ammonium persulfate activated with sodium bisulfite was used as initiator, and the time was twenty hours. In the first two cases, no polymer was obtained, and the trinitrostyrene was recovered. With 0.4% of the trinitro compound, a yield of 20% of polymer was obtained. The styrene, under the same conditions, polymerized almost quantitatively. (d) Emulsion with Isoprene.-When mixtures of styrene, trinitrostyrene and isoprene were heated a t 50’ for twenty-three hours in emulsion with the persulfate-bisulfite combination, the trinitrostyrene was recovered un- JAMES N. COKER Vol. 72 changed. The same result was obtained when the styrene was omitted; under the same conditions, styrene and isoprene (80:20) gave a good yield of polymer. (e) Solution with Maleic Anhydride.-When maleic anhydride was heated in benzene solution with trinitrostyrene (with and without styrene) and with benzoyl peroxide as the initiator, no polymer was obtained. Under the same conditions, the styrene/maleic anhydride heteropolymer began to precipitate in fifteen minutes. Summary 2,4,6-Trinitrostyrene has been prepared, but efforts t o polymerize it under various conditions and to. copolymerize i t with isoprene, maleic anhydride, or styrene have failed. It acts as an inhibitor of styrene polymerization. LOUISVILLE, KENTUCKY RECEIVED OCTOBER 1949 10, [CONTRIBUTION THENOYES FROM CHEMICAL LABORATORY, UNIVERSITY ILLINOIS] OF The Synthesis of Vulpinic Acid from Polyporic Acid1 By ROBERT FRANK, L. GEORGE CLARK AND JAMES N. R. In this communication we wish to report the oxidation of the fungus pigment polyporic acid (111)2 means of lead tetraacetate. This reacby tion has been made possible a new and total synthesis of vulpinic acid (VII)3and an examination of some of ibderivatives, notably the “isovulpinic acid” described by S ~ i e g e l . ~ Br 0 v 0 COmR the natural source.s Culture of the fungus has also not been a feasible source, because the pigment occurs only in the fruit body and not in the myceli~m.~ The synthesis of polyporic acid (111) was accomplished by a modification (1-11-111) of the method of Shildneck and Adams.’O I n addition to OH 0 Dr \ - v I I1 Vulpinic acid is a yellow pigment found in a variety of lichens. Its structure was elucidated mainly by Spiege13and by Karrer, Gehrckens and HeussI6 and confirmed by synthesis by Volhard.6 It has recently been observed to be a powerful antibacterial agent in vitro.7 Polyporic acid (111)for this study was obtained both from the natural source, the fruit body of Polyporus rutilans, and by synthetic means. The rarity of the fungus, however, limits the value of (1) Presented before the Division of Organic Chemistry at the Atlantic City meeting of the American Chemical Society, September 18-23, 1949. (2) Kogl, Ann., 447,78 (1926); Kdgl and Becker, ibid., 466, 219 (1928). (3) Spiegel, ibid., 819, 1 (1883). (4) Spiegel, ibid., 819, 15 (1883). (5) Karrer, Gehrckens and Heuss, Hclu. China. Acta, 9,446 (1926). (6) Volbard, Ann., 888, 1 (1894). (7) Stoll. Renz and Brach, E z p ~ i c n t i 3,, 111, 115 (1947). ~ OH 111 the elimination of two steps of the previous method, the preparation of the starting material, 2,5-diphenyl- 1,4-benzoquinone (I), has been improved by use of nitrous acid rather than chromic acid in oxidizing the mixture of quinone, quinhydrone and hydroquinone obtained in the phenylation of 1,Pbenzoquinone. Fieser l1 has recently observed that nitrous acid is specific for this type of oxidation. Reaction of lead tetraacetate with polyporic acid in boiling acetic acid occurs smoothly to give (8) Polyporus ~ l i l a n s P . nidulans) is reputed t o be fairly com( mon in some areas, notably Pennsylvania. The coliperation of a number of collectors during the relatively dry summer and fall of 1948, however, netted the authors less than an ounce of the dried fungus. (9) Private communication, Dr. Leland Shanor and Mr. Richard K. Benjamin: see the following paper. JOURNAL, 68, 2373 (1931). (10) Shildneck and Adams, THIS (11) Fieser, ibid., 70,3165 (1948).