[CONTRIBUTION FROM THE SCHOOL OF CHEMISTRY OF THE UNIVERSITY OF MINNESOTA]
QUINONES BY THE PEROXIDE OXIDATION O F AROMATIC COMPOUNDS RICHARD T. ARNOLD
AND
RAYMOND LARSON
Received December 11, 1939
An attempt to prepare 1-naphthoic acid from the aldehyde using perhydrol in glacial acetic acid gave only a small quantity of the carboxylic acid and workable amounts of 1,4-naphthoquinone. If the acid was not isolated the quinone could be obtained in a yield of twenty-seven per cent. In contrast to the work of Charrier (1) it has been shown that naphthalene can be oxidized under similar conditions to give a twenty per cent yield of 1 ,Fnaphthoquinone. The conditions of the reaction cannot be changed materially without seriously affecting the yield of quinone. It has been reported (2) that anthracene yields anthraquinone and 9 ,9’-dianthrone, and that phenanthrene gives diphenic acid. These results have been confirmed. Because of the present interest in quinones, due primarily to the investigations with vitamins E, K1, and Kz, the products of bacterial metabolism, and carcinogenic substances, we have extended the reaction to include 1,2-bensanthracene, pyrene, and alkyl derivatives of benzene and naphthalene. All of these hydrocarbons form the expected quinones. A typical reaction is shown in formula I.
The yields vary over a wide range depending on, and increasing with, the reactivity of the aromatic nucleus toward oxidation. It should be pointed out that 1,2-benzanthracene differs from anthracene in that the quinone is formed as the chief product. Boeseken (3) has shown that certain aromatic aldehydes react with peracetic acid to replace the formyl group with acetoxy in good yields. This reagent, however, when tried on hydrocarbons gave practically no quinone. 250
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The authors are indebted to Professors L. I. Smith, W. E. Bachmann, and L. F. Fieser for many compounds used in this study. EXPERIMENTAL
Oxidation of 1-naphthaldehyde. A solution containing 4.03 g. of 1-naphthaldehyde in 80 cc. of glacial acetic acid waa treated with 25 cc. of perhydrol and heated on a steam-bath. Within fifteen minutes the solution turned yellow, and in time, t o cherry red. The solution was concentrated by removal of half the solvent, and water was added dropwise until precipitation began. Two crops of crystals were collected; m.p. 124-125'; yield 1.1 g. A mixed melting point determination with an authentic sample of l14-naphthoquinone proved the identity of the material. Oxidation of naphthalene. Several attempts failed, but the following directions proved satisfactory. Ten grams of naphthalene, 25 cc. of perhydrol, and 50 cc. of acetic acid were heated together just above 80" for forty-five minutes. The volume of the solution was reduced to half by direct distillation a t atmospheric pressure. Water was added slowly until crystallization started. The first crop melted a t 121-125", and the second began to melt at 115". The odor of naphthalene was evident in the second crop. After recrystallization, a twenty per cent yield of the quinone was obtained. Duroquinone. Five grams of durene in 50 cc. of glacial acetic acid containing 25 cc. of perhydrol was heated on a steam-bath for fifteen hours. After the bulk of the solvent was removed at diminished pressure, the material was steam distilled. The substance weighed 2.1 g. and melted a t 110-111'. A mixed melting point determination with pure duroquinone gave no depression. o-Xyloquinone. The procedure for duroquinone was followed, except that the temperature was held at 120" for twenty hours; only a trace of the yellow quinone was obtained. Practically all of the hydrocarbon was recovered in the steam distillation. 2-Methyl4 ,&naphthoquinone. Five grams of the hydrocarbon was dissolved in 75 cc. of glacial acetic acid and warmed to 50'. To this was added 15 cc. of perhydrol, and the mixture was allowed to stand a t 80" for ten hours. An inductive period of ten minutes was followed by the usual color changes. After evaporation of the solvent and steam distillation, 1.8 g. (30%) of the quinone waa obtained. The melting point was 104-105" and the identity was shown by mixed melting point with an authentic sample from Dr. Fieser. 2,S-Dimethyl-1,4-naphthoquinone. Following the above directions for the monomethyl derivative we obtained without steam distillation a seventy-eight per cent yield of product; m.p. 127'. 1 ,I-Benzanthraquinone-9,10.One gram of pure l12-benzanthracene was dissolved in 30 cc. of glacial acetic acid, and 5 co. of perhydrol was added. The solution was heated to boiling and the flame removed. The exothermic reaction caused the mixture to continue refluxing for an additional 10 minutes. The heating was continued for twenty minutes, and the entire solution then poured into cold water. The finely divided precipitate was collected by centrifuging. The solid was recrystallized twice from acetic acid and melted at 158-160". A red impurity was removed by sublimation. The sublimate, after recrystallization, weighed 0.52 g. (46%) and melted at 166-167". Ozidation of pyrene. To 5 g. of pyrene in 80 cc. of boiling glacial acetic acid, 25 cc. of perhydrol was added. After refluxing for twenty minutes, the reactionmixture was poured into cold water. The reddish precipitate was collected and
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RICHARD T. ARNOLD AND RAYMOND LARSON
dried; i t weighed 5.1 g. This material is a mixture of the 3,8- and 3,lO-pyrene quinones as shown by our inability to obtain a pure quinone by crystallization The product was completely reduced by sodium hydrosulfite in the usual manner. Because of the difficulty involved (4), separation of these two compounds was not attempted. SUMMARY
1. It has been shown that many aromatic hydrocarbons and their simple derivatives can be oxidized by thirty per cent hydrogen peroxide in glacial acetic acid to give quinones. 2. The yields are comparable to those obtained by dichromate oxidation. 3. It seems that the greatest value of the reaction lies in the selective oxidation of alkyl polycyclic derivatives. MINNEAPOLIS, MINN.
REFERENCES (1) CHARRIER AND MOGGI,Guzz. chim. itul., 67,736 (1927). (2) CHARRIER AND CRIPPA,Gum. chim. itul., 67, 741 (1927). (3) BOESEKEN, COHEN,AND KIP, Rec. truu. chim., 66, 815 (1936). (4) VOLLMANN, BECKER,CORELL,AND STREECK, Ann., 631,6 (1937).
