PROCEEDINGS
OF THE TOMSK ORDER OF THE RED BANNER OF LABOR
POLYTECHNIC INSTITUTE NAMED AFTER S. M. KIROV

Volume 196
1969

ACID CLEAVAGE OF PHENANTHRENE DIMETHOXYPEROXIDE

V. P. SHABROV, A. G. PECHENKIN, A. K. LEBEDEV

(Submitted by the Scientific-Methodological Seminar of the Faculty of Chemical Technology)

Phenanthrene dimethoxyperoxide, readily isolated from the products of ozonolysis of phenanthrene in methanol [1], can serve as a starting material for obtaining a wide variety of oxygen-containing 2,2′-substituted diphenyls. The ready availability of dimethoxyperoxide, owing to the method of ozonolysis of technical phenanthrene developed in our laboratory [2, 3—4], provided the stimulus for a detailed study of its chemical properties. It is known that carrying out the heterolytic cleavage of dimethoxyperoxide in aliphatic alcohols in the presence of organic and inorganic bases gives, in high yield, 2′-formyldiphenyl-2-carboxylic acid or its methyl ester [1, 4—5]. When organic solvents are replaced by aqueous media, a strong decrease in the rates of the reactions taking place is observed. Thus, hydrolysis of dimethoxyperoxide with aqueous solutions of caustic alkalis continues for up to 3 hours. In an attempt to hydrolyze dimethoxyperoxide with water on heating to 100°C, it was observed that in 6 hours the degree of its conversion did not exceed 2–3%. It is known that the cleavage of organic peroxides is catalyzed by strong inorganic acids. Since the acid cleavage of phenanthrene dimethoxyperoxide had not previously been studied by anyone, we investigated this process.

As a result of this study it was established that the heterolytic cleavage of dimethoxyperoxide proceeds smoothly in aqueous media in the presence of strong inorganic acids, with the formation of diphenic aldehyde, hydrogen peroxide, and methanol. Depending on the temperature at which the process is carried out and on the concentration of the acid used, the reaction of acid cleavage of dimethoxyperoxide at 80—100°C proceeds in 10—40 minutes. The diphenic aldehyde formed at this stage is quantitatively isolated by simple filtration.

Comparing this method of obtaining diphenic aldehyde with known methods for preparing it from iodbenzaldehyde by Ullmann condensation [6], from 2,2′-dimethyldiphenyl by bromination followed by saponification [7], and also by ozonolysis of pure phenanthrene in various solvents without isolation of ozonides [8], we see that it is the simplest and does not require the use of scarce reagents such as iodine or bromine.

Diphenaldehyde may find application in a number of syntheses of substituted dibenz-\([c,e]\)azepines [9] and, by analogy with known methods [10, 11], may be used to obtain polymers with special properties. We used diphenaldehyde for the synthesis of 2′-hydroxymethyldiphenyl-2-carboxylic acid (diphenyl hydroxy acid), which, owing to the presence of two functional groups—alcohol and carboxyl—may also find broad application in the synthesis of polymeric materials and biologically active substances, and for obtaining diphenic acid.

All known methods for obtaining diphenyl hydroxy acid are based on the Cannizzaro reaction, to which diphenaldehyde is subjected when treated with alkalis. Diphenaldehyde II, obtained by acid hydrolysis of dimethoxy peroxide I, upon subsequent treatment with dilute alkali solutions was converted into diphenyl hydroxy acid III according to the scheme:

\[ \begin{array}{c} \text{I} \quad \xrightarrow[\mathrm{H_2O}]{\mathrm{H^+}} \quad \text{II} \quad \xrightarrow[\mathrm{H_2O}]{\mathrm{OH^-}} \quad \xrightarrow{\mathrm{H^+}} \quad \text{III} \end{array} \]

Experimental Part

10 g of dimethoxy peroxide are mixed with 30 ml of a 7% aqueous HCl solution, heated to 100°C and, with stirring, kept for 15 min. During this time the dimethoxy peroxide is quantitatively converted into diphenaldehyde, which is isolated by filtration. M.p. 58°C. Literature m.p. 63°C [8].

Dioxime m.p. 185°C. Literature m.p. 184–186°C [1].
Calculated: N—11.65%.
Found: N—11.62%.

The entire diphenaldehyde is mixed with 25 ml of a 10% solution of NaOH (KOH), and with stirring the mixture is heated to 95°C and held for 20 min. After cooling, the resulting solution is filtered, and the filtrate is acidified with a 15% solution of hydrochloric or sulfuric acid to pH 3. The large white crystals of 2′-hydroxymethyldiphenyl-2-carboxylic acid that precipitate are filtered off, washed with water, and dried. 8.26 g are obtained, 98.5% based on dimethoxy peroxide. M.p. 142–143°C. Literature 143°C [4].

Calculated for \(\mathrm{C}_{14}\mathrm{H}_{12}\mathrm{O}_3\): C—73.67%; H—5.28%.
Found: C—74.00%; H—5.23%.

Neutralization equivalent:
Calculated 228.2.
Found 229.

Sterrok et al. [12] attempted to use 65% technical phenanthrene to obtain diphenyl hydroxy acid, but were unable to isolate individual compounds. Here, too, it should be emphasized that the method we propose makes it possible to obtain diphenyl hydroxy acid—

...through dimethoxy peroxide in high yield from technical-grade phenanthrene; moreover, the quality of the diphenic alcohol acid thus obtained is higher than when it is obtained from pure phenanthrene by known methods.

REFERENCES

1. P. S. Bailey, J. P. Org. Chem., 23, 1089, 1958.
2. L. P. Kulev, V. A. Salskii. USSR Author’s Certificate 1337926 of 10 May 1961.
3. L. P. Kulev, V. A. Salskii, A. K. Lebedev, V. P. Shabrov. Journal of the D. I. Mendeleev All-Union Chemical Society, 7, No. 5, 599, 1962.
4. Sturrok et al. J. P. Org. Chem., 28, 2340—43, 1963.
5. A. K. Lebedev, A. N. Novikov. Izv. TPI, 151, 311, 1966.
6. F. Mayer. Berichte, 44, 2298, 1911; 45, 1107, 1912.
7. F. Kenner, G. Turner. J. P. Chem. Soc., 99, 2112, 1911.
8. Syntheses of Organic Preparations. Collected Papers No. 12, 60, Moscow, 1964.
9. P. O. Hawthorne, E. L. Michelic, M. S. Morgan and M. H. Wilt, J. P. Org. Chem., 28, 10, 2831—35, 1963.
10. Yu. A. Popov, B. E. Davydov, N. V. Shishkina, B. A. Kreshchel. Izv. AN SSSR, No. 11, 2014, 1963.
11. Yu. V. Mitin, Yu. N. Sazonov, G. P. Vlasov, M. M. Koton. High-Molecular Compounds, 2, 5, 716, 1960.
12. M. Sturrok et al. U.S. Patent 2898350; see RZhKh, 74814 p, 1960.