NOVEMBER, 1964
SYNTHESIS AND OZONOLYSIS OF BENZO [c]PHENANTHRENE
sity of the signals shown in Fig. 3 was estimated by assuming that there were 34 protons in the methyl octadecadienoate ligand. Complex I (30 mg.) was decomposed by heating with alkali under conditions used for isomerization (6.6% KOH in ethylene glycol, 180', 45 mi^^.).^* A finely divided black precipitate was filtered and identified as iron. The resulting conjug'ated diene had a230mp 71.2 compared with 85.6 for methyl linoleate conjugated under the same conditions. Decomposition with FeCl3I* &'as carried out by dissolving 0.194 g. of complex I in 10 ml. of 95'30 ethanol solution saturated with FeC13 and by stirring occasionally for 30 min. Water was added, and the mixture was extracted with petroleum ether yielding 0.128 g. of conjugated diene (recovery 97%; a t 231 mp gave e 25,400 and a t 10.14 p gave e 218, due to trans,trans conjugation). Decomposition of 0.213 g. of complex I with triphenylphosphine" (0.265 9.) was carried out by heating a t 150' in an evacuated tube for 12 hr. A solid yellow precipitate formed and was extracted with petroleum ether. Infrared of the fatty extract (run a s a smear) showed a decrease in carbonyl bands a t 4.88 and 5.05 p and a strong band a t 10.14 p due to trans,trans conjugation. Complex I was also decomposed by KMn04-KI04 oxidation. A mixture of mono- and dicarboxylic acids was obtained and analyzed to determine the position of double bonds in the dienoic ligand. Oxidation with KMn04KIOa was also carried out on the conjugated dienes obtained after decomposition of the complex with FeC13(Table 11). Complex I (0.20 g.) was stirred in a manometric system under 1 atm. of hydrogen with a reduced palladium catalyst (5% on (38) B. A. Brice, M. L. Swain, S. F. Herb, P. L. Nichols, Jr., and R. W. Riemenschneider, J . A m . Oil Chemiats' s o c . , 29, 279 (1952).
3297
alumina, 0.16 g.) in 4 ml. of acetic acid. N o hydrogen waa absorbed after 1 hr. a t 30". Under the same conditions 1.9 mmoles of methyl linoleate absorbed 1.7 mmoles of hydrogen. Analysis of the hydrogenated product showed complete conversion to methyl stearate. When complex I(0.030 9.) was added to methyl linoleate (0.12 g.), hydrogenation proceeded slowly and after 5 hr. reached 60% of theory. Analysis of the product showed 97.3% monoene, 2.3% conjugated dienes, and 0.4% methyl stearate. Complex I (0.127 g., 0.29 mmoles) was heated with methyl linoleate (0.871 g., 2.96 mmoles) in a tube with nitrogen bubbling. The mixture was analyzed after 2 hr. a t 150" (diene 77.2, conjugated dienes 13.3, and complex 9.5y0); after 3 hr. a t 160' (diene 78.2, conjugated dienes 16.1, and complex 5.7'3,); and after 4 hr. a t 180" (diene 82.1, conjugated diene 17.9, and complex 0 % ) . In another experiment, a solution of complex I(0.213 g.) in 40 ml. of cyclohexane was heated under 400-p.8.i. hydrogen pressure in a 150-ml. autoclave with agitation for 1 hr. a t 150' ( A n a l . Found: stearate, 7.0; monoene, 6.3; diene, 1.4; conjugated diene, 49.3; complex, 36.0), and for 2 hr. a t 180' ( A n a l . Found: stearate, 53.6; monoene, 44.0; complex, 2.4).
Acknowledgment.-We are grateful to C. A. Glass for the n.m.r. analyses, Mrs. Clara E. McGrew and Mrs. Bonita Heaton for elemental analyses, Drs. J. C. Cowan, H. J. Dutton, and R. B. Bates (University of Arizona) for helpful discussions, and Dr. W. F. Kwolek (ARS Biometrical Services) for the statistical analysis.
Synthesis and Ozonolysis of Ben~o[c]phenanthrene'-~ EMILJ. MORICONI, LUDWIG SALCE, AND LUBOMYR B. TARANKO Contribution N o . 738 f r o m Fordham University, Department of Chemistry, New York, N e w York Received April 27, 1964 Gram quantities of benzo[c]phenanthrene (1) were prepared by a modification of the Szmuszkovicz and Modest procedure. Predictably, on the basis of our published oxidation-reduction potential hypothesis, ozonization of 1 in methylene chloride proceeded slowly to yield an initial peroxidic solid (2). Alkaline hydrogen peroxide oxidation of 2 led to the 5,6-bond-cleavage product, l-(o-carboxyphenyl)-2-naphthoic acid ,(3), in 30Q/, crude yield; 40% of unreacted 1 was recovered. Compound 3 was identified as its dimethyl ester (4).
A number of reliable, multistep syntheses of berizo [ c ] phenanthrene (1) are available in the l i t e r a t ~ r e . ~Com-
produce 2-5-g. quantities of 1 were successful only with an experimental modification of the Szmuszkovicz and Modest procedure. 4g,5
a
11
Ozonolysis Results
1
mon to all is the last-step production of milligram (or unspecified) 4b quantities of 1 by either dehydrogenation4b-f or decarb~xylative~~,g techniques. In our hands attempts to scale up each of these syntheses to (1) Paper XI11 in the series entitled "Ozonolysis of Polycyclic Aromatics." Paper X I I : E. J. Moriconi and F. A. Spano, J . A m . Chem. Soc., 88, 38 (1964). Presented in part at the Symposium on Ozone Chemistry, 135th National Meeting of the American Chemical Society, Atlantic City, N. J., Sept., 1959. (2) Thia research was supported by Public Health Service Research Grant No. CA-03325-06 from the National Cancer Institute. (3) Ozonization of five (triphenylene, chrysene, naphthacene, pyrene, and benz [alanthracene) of the six possible quadricyclic benz-fused aromatics has been reported to date. This paper completes the sextet. (4) (a) J. W. Cook, J . Chem. Soc.. 2524 (1931); (b) C. L. Hewett, abid., 596 (1936); (c) M. S. Nowman and L. M . Joshel, J . A m . Chem. Soc., SO, 485 (1938); (d) W. E. Bachman and R . 0. Edgerton, i b i d . , 62, 2970 (1940): (e) E . D. Bergmann and 2. Pelchowicz, J . Org. Chem., 19, 1383 (1954); ( f ) W. Davies and Q. N. Porter, J . Chem. Yoc., 4967 (1957); (9) J . Szmuszkovicz and E. J. Modest, J . A m . Chem. S o c . , 70, 2542 (1948); i b i d . , 72, 566 (1950).
Compound 1 showed expected resistance toward ozone oxidation. It was only after a large excess of ozone (10 mole equiv.) had been passed through a solution of 1 in methylene chloride that 0.6 mole equiv. of ozone reacted. The white, gelatinous, peroxidic product 2, on further oxidation with alkaline hydrogen peroxide, ultimately led to a 30% yield of crude 1-(o-carboxyphenyl)-2-naphthoic acid (3). Some 40% of unreacted 1 was recovered. Compound 3 adhered tenaciously to other organic acid impurities which caused erratic elemental analyses and neutralization equivalents, and which could not be removed by recrystallization and chroniatographic techniques. Ultimately 3 was converted to its known dimethyl ester (4) which was purified by liquid-solid chromatography. Compound 4 was independently prepared (a) via peracetic acid oxidation of benzo [c]phenanthrene-5,6-dione (5) to 3, followed by esterification to 4, and (b) directly, by a mixed Ullinann condensation of methyl 1-bromo-2-naphthoate ( 6 ) and methyl o-iodobenzoate ( 7 ) . 4 e (5) See Experimental
MORICONI, SALCE, AND TARANKO
3298 1
t
peroxidic solid
t
2
I COOR
3,R=H
5
4, R = CHs
Experimental6 Preparation of 1 via Modified Szmuszkovicz and Modest Maleic Anhydride Double Adduct (8) .-A mixture of 100 g. (0.49 mole) of 1-phenyldialins and 250 g. (2.55 moles) of maleic anhydride was heated a t 150-160" with vigorous stirring for 20 hr. On slow cooling, crystals separated. To this solid mixture was added 150 ml. of glacial acetic acid and the whole was vigorously stirred for 48 hr. The crystalline product was then filtered, and washed successively with acetic anhydride, methanol, and petroleum ether (b.p. 30-60"), to yield 111 g. (57%)9 of cream-colored adduct ( 8 ) , m.p. 318-319" dec. (1it.Q m.p. 315-316" dec. Benzo [c]phenanthrene-5,6-dicarboxylicAcid Anhydride (9).loIn the best of a series of runs, a mixture of 200 g. of 8, 20 g. of 30% Pd-C, and 1.5 1. of p-cymene was refluxed with stirring for 20 hr. The mixture was filtered while hot to remove the catalyst. Upon concentration and cooling, 50 g. of crude 9 was obtained from the filtrate. Extraction of the catalyst-containing residue with boiling n-butyl acetate afforded an additional 42 g. of 9, as well as 40 g. of unreacted 8. Based on the amount of 8 reacted, the total yield of crude 9, m.p. 247-251", was 78%; recrystallization from n-butyl acetate or acetic anhydride led to pure 9, m.p. 257-258' (lit.4em.p. 257-258'). Benzo[c]phenanthrene (1) .'Z-Anhydride 9 (23 g.) was refluxed for 2 hr. with 230 ml. of freshly distilled quinoline and 10 g. of electrolytic copper powder. The cooled solution was diluted with ether, filtered, washed with dilute hydrochloric acid and dilute sodium carbonate solution, dried by filtration through a layer of anhydrous sodium sulfate, and distilled under reduced pressure. The hydrocarbon distilled a t 250-300" (10 mm.) as a yellow oil which soon solidified. It was converted directly to the picrate for purification. The latter was recrystallized twice and decomposed with dilute ammonium hydroxide to give the free hydrocarbon which was crystallized from absolute ethanol. procedure.'^
(6) Melting points were determined on a Kofler micro melting point a p p a r a t u s a n d are corrected. Boiling points are uncorrected. T h e microanalyses were performed b y Schwarzkopf Microanalytical Laboratory. T h e infrared spectra were run o n a Perkin-Elmer Model 137 spectrophotometer. As previously reported, special caution was exercised and protective devices were employed' in handling carcinogenic l. (7) E . J. Moriconi and L. B. Taranko, J . O r g . Chem., 28, 1831, 2526 (1963). (8) R . Weiss, "Organic Syntheses," Coll. Vol. 111, John Wiley a n d Sons, Inc., 1955, p. 725; now obtainable from hldrich Chem. Co. (9) With increased quantities of reactants (I60 g. of phenyldialin and 400 g. of maleic anhydride), the maximum yield of 8 obtainable by us was 41%.
(IO) T h e authorsag quantitatively dehydrogenated 8 t o 9 b y careful heating with a large excess of sulfur. I n fairly large scale runs, difficulty of reaction control a n d separation of the very tarry products led US t o the use of Pd-C in p-cymene as the dehydrogenating agent.11 (11) C. Ainsworth, J . A m . Chem. Sac.. 79, 5242 (1557); J . P . Burnett, J r . , and C. hinsworth, J . Org. Chem., 2 3 , 1382 (1958). (12) T h e most serious obstacle encountered in the translation of the Sznluszkovicz a n d Modest yrocedure4K t o larger runs was the decarboxylation of 9 t o 1. Heating a finely ground mixture of 9 , barium hydroxide, and copper bronze, a n d distilling the rnisture zn vacuo as reported, gave only trace amounts of 1 or no isolable products a t all. The use of a copper chromite catalyst (37K.kF)'s produced no marked irnprovernent in yield. 1)ecarboxylation attempts cia Hofnlann degradation rnet with failure, as did oxidative experiments with lead dir,xiile and lead tetraacetate,14 and phosphorus pentoxirle.ls Ultiniately, FIenitt's prore(1ure was employed.la ( 1 3 ) 11,S.Neurrian and A. I. Kusak, .I. O r g . Chem., 14, 375 (1945). ( 1 4 ) C. .I, rob. 31, Ohta, E. Rpnk. a n d .i. R'eiss, H e l u . Chirn. iiclo, 41, 1101 (1958). (15) V. R . Skvarchenko. L. V4en-lyan, and R . Ya Lexina, Z h . Obshch. K h i m . , Sa, 1023 (1982); .I. G e n . Chem. CSSR. 33, 1002 (1062). (16) C. I.. H e a i t t , J . Chem. S o c . . 1286 (1938).
VOL. 29
The fine, silky needles of 1 melted a t 67-68" (lit.(p m.p. 68"); yield 2.5 g., 14y0. The picrate formed as ruby red needles (from ethanol), m.p. 126-127" (lit.4a m.p. 126-127'); the 2,4,7-trinitrofluorenone complex precipitated as reddish orange needles (alcohol-benzene) , m.p. 169-170" (lit.I3 m.p. 170.8-171.1"), which could be decomposed with tin and hydrochloric acid'' to recover 1. Ozonolysis of Benzo[c]phenanthrene (1 ).-Into a cold (-78"), colorless solution of 1.14 g. (5 mmoles) of 1 in 100 ml. of methylene chloride'" was passed an ozone-oxygen stream containing 3.5 vol. 70of ozone.18b The reaction proceeded very slowly as evidenced by the almost immediate liberation of iodine in the potassium iodide trap. A fine, white precipitate appeared with progress of the reaction. The ozonization was stopped after passage of 10 mole equiv. of ozone through the reaction mixture which now had acquired the blue color of dissolved ozone. Titration of iodine in the trap indicated that, 0.6 mole equiv. of ozone had reacted with 1. The precipitate was filtered off to give a white, gelatinous solid. The latter showed properties characteristic of peroxides; i.e., it darkened slowly on standing, sparkled when burned in a flame, and liberated iodine from an acidiSed iodide solution. The material melted a t 133-143". Its infrared spectrum (KBr) was uninformative except for a broad carbonyl band. Generally, however, this peroxidic material was not isolated and the ozonization mixture as a whole was further oxidized by the addition of 20 ml. of a 10% sodium hydroxide-30% hydrogen peroxide solution. Compound 1 itself was found to be inert toward this treatment. After stirring for 12 hr. the inorganic layer (A) was separated from the and yellow organic layer (B) extracted successively with 25-1111. portions of methylene chloride and ether. The aqueous solution was boiled for 5 min. (to remove traces of organic solvents), cooled to room temperature, and acidified by careful addition of dilute (10%) hydrochloric acid. The resultant emulsion was extracted with three 25-ml. portions of ether. The combined organic extracts were dried (anhydrous sodium sulfate) and the solvent was allowed to evaporate at room temperature. The slightly yellow residue was repeatedly dissolved in acetone and reprecipitated by addition of a few drops of water to give, ultimately, 0.44 g. (30%) of crude 3 as a white solid, m.p. 230-235'. All conventional methods of purification of this organic dicarboxylic acid were fruitless. Ultimately, the impure acid was dissolved in a few milliliters of ethanol and treated with an ethereal solution of diazomethane. The yellow residue left after evaporation of the solvents was dissolved in 15 ml. of carbon tetrachloride and applied to the top of a 40 X 2 cm. Florisil-packed column. Elution with the same solvent and evaporation of the latter gave 0.38 g. of methyl 1-(o-carbomethoxypheny1)naphthalene-2carboxylate (4) as an oily semisolid, b.p. 183-185" a t 0.6 mm. 5.79 s. (1it.l. b.p. 2OC-205" a t 0.75 mm.), infrared ::A: Anal. Calcd. for C20H1604: C, 75.00; H, 5.00. Found: C, 75.15, 74.91; H, 4.42, 4.94. The identity of 4 was firmly established by comparison with an authentic sample (superimposable infrared spectra, and identical desorption temperature and retention time on gas chromatographic analysis) prepared by (a) a mixed Ullmann reaction of methyl 1-bromonaphthalene-2-carboxylate (6) and methyl 2-iodobenzoate (7),4e and (b) peracetic acid oxidation of benzo[c]phenanthrene-5,6-dione( 5 ) (vide infra). The free acid 3 has not been reported in the literature. Organic layer B was repeatedly washed with 107' aqueous sodium bicarbonate, water, dilute hydrochloric acid, and again water, and dried over anhydrous sodium sulfate. Evaporation of solvents gave a yellow oil which was chromatographed on Florisil (3:1 ligroin-benzene) to recover 0.45 g. (2 mmoles) of 1. Preparation of Benzo[c]phenanthrene-5,6-dione (5) .-Aromatic anhydride 9 (1 g.) was boiled with 20 ml. of acetic acid and 2 g. of sodium chromate for 2 hr. The dark green solution on (17) M.Orchin a n d E. 0. Woolfolk, J. A m . Chem. Soc., 68, 1727 (1946). (18) (a) I n earlier stages of this research, attempts were made t o ozonize 1 in polar solvents: methanol, methanol-methylene chloride, acetic acid, and acetone. All of these solutions absorbed ozone less readily than solutions of methylene chloride. Oxidative or reductive work-up of the oils remaining after solvent removal left oily products consisting of 1 (>EO%) and resinous, intractable materials which defied separation a n d identification. Compound 1 in solvent methylene chloride also absorbed ozone slowly, b u t visual evidence of an occurring reaction was provided b y the appearance of a white, gelatinous precipitate; this solvent was used in all of the approximately 40 runs attempted. (bj T h e use of ozone-nitrogen led t o no significant differencein results.
NOVEMBER, 1964
SYNTHESIS AND OZONOLYSIS O F BENZO [CIPHENANTHRENE
3299
8.)
dilution with cold water deposited a red solid material. Ex5,6-bond (1.44 has less double bond character than traction of the precipitate with cyclohexane gave on cooling the the corresponding 9,lO-bond in phenanthrene. dione (5), 0.35 g. (3973, which on recrystallization from the Experimentally, Badgerz4has reported that the addisame solvent melted a t 185-186" (lit.(* m.p. 187-188'). tion of double bond reagent, osmium tetroxide, to 2The phenazine derivative, prepared by refluxing 0.05 'g. of methylbenzo [clphenanthrene is too slow to measure dione 5 with 0.05 g. of o-phenylenediamine in 10 ml. of acetic acid for 5 min., gave yellow needles, melting a t 186-187' (lit.la kinetically. Apparently such addition to parent hydrom.p. 189-190'). carbon 1 has not been reported, or is predictably even Peracetic Acid Oxidation of Benzo[c]phenanthrene-5,6-dione more reluctant to proceed via the initial cyclic addition (5).-A solution of 0.5 g. of 5 in 50 ml. of sym-tetrachloroethane product. If the mechanism of ozonolysis of 1 isanalowas refluxed with a mixture of 100 ml. of glacial acetic acid and 50 ml. of 307, hydrogen peroxide for 10 hr. After about 5 min. gous to that proposed for phenanthrene,z6then formaof refluxing the initially dark red organic layer changed to a tion of the cyclic primary ozonide across the 5,6-bond slightly yellow color. The solvents were removed by vacuum in 1 also is retarded. Experimentally, the 5,6-bond is distillation to leave a yellow oil. The oil was stirred with a slow to react with ozone, and 5,6-bond cleavage occurs saturated aqueous sodium bicarbonate solution which dissolved most of the material. Filtration removed a small amount of a only after a large excess of ozone had passed through the yellow solid. Acidification of the filtrate with 10% hydrochloric solution. acid produced an emulsion which was extracted with several 25Recently, however, the crystal structure of 1 has been ml. portions of ether. Evaporation of the solvent gave a yellow redetermined at room temperature by full three-dinienoil which was difficult to crystallize. It was repeatedly dissolved sional X-ray analysis.z6 These studies do not support in acetic acid and reprecipitated by addition of a few drops of water to form, ultimately, 0.21 g. (387,) of crude 3 as a white the Herbstein and Schmidt speculations on charge powder, m.p. 227-229". This impure dicarboxylic acid again relocalizations at C-3 and C-5, nor do bond lengths show sisted all efforts to obtain an analytically pure sample. Ultianomalies which were interpreted favoring such hybridmately, it was esterified by treatment with diazomethane to give ization. These conflicting theoretical conclusions a yellow viscous oil which was purified by chromatography to serve as a reminder that any comparison based on a yield 4 identical with that prepared via ozonolysis and by the Ullmann reaction. measurement of a molecule at "rest" (X-ray crystalloReduction of 5 to 1 with Lithium Aluminum H ~ d r i d e . ~ l , ~ ~ -graphic analysis), where conformational changes during Compound 5 (1.4 9.) was placed in a thimble in a Soxhlet and chemical reactions are ruled out, and a "reacting" was extracted into a solution of lithium aluminum hydride (2.0 niolecule (with 03)in an activated state is at best dubig.) in boiling tetrahydrofuran (250 ml.). The solution was allowed to reflux for 19 hr. The cooled solution was then deous speculation. composed with moist ether. Approximately 250 ml. of l N HC1 It is worthy of note that the site and resistance to was added. The ether layer was separated off and the water ozonolysis were predictable on the basis of our published layer was extracted twice with 50-ml. portions of ether. The oxidation-reduction potential h y p o t h e s i ~ . ~The ~ corether extracts were combined and dried over anhydrous sodium rected oxidation-reduction potential of benzo [clphensulfate. The solvent was then removed, in vacuo, on a water bath maintained a t 50". The dark red residue obtained was disanthrened16-dione(0.442 v.) 28 indicates the 5,6-bond in solved in carbon tetrachloride and filtered to remove a small 1 to be most susceptible to ozone attack. However, a amount of insoluble material. This solution was then placed on comparison of the corrected oxidation-reduction potena 2.5 X 25 cm. alumina column (Woelm grade I neutral) and tials for the four quadricyclic benz-fused aromatics3 eluted with carbon tetrachloride. A blue fluorescent band, visible with ultraviolet light, was eluted off the column first. containing a phenanthrene-type 9,lO-bond suggests the This blue fluorescent band, containing 1, was sensitive to ultraorder of increasing difficulty of ozonolysis in the series: violet light in the presence of alumina and caused the column to benz [alanthracene (5,6-bond, 0.380 v.) pyrene (4,5-, turn yellow-brown in color. Therefore, elution of the desired 0.424) < chrysene (5,6-, 0.440) l.27t2* band was followed by briefly exposing 50-ml. fractions of the carbon tetrachloride eluate to ultraviolet light to see if they fluoresced. The fractions having a blue fluorescence were com(22) C. Reid's [ J . Mol. Spectrzl, 1, 18 (1957)l perspective drawing of 1 bined. Removal of the solvent yielded a viscous yellow-brown based on Herbstein's and Schmidt's*l analysis is shown in 10; the diagonals oil which solidified to a wax-like substance on cooling, yielding across which the benzene rings fold are shown dotted. 0.484 g. (40y0) of crude 1, m.p. 51-55', Pure 1, m.p. 64-66', was obtained via the picrate.
