aqueous solutions with the same content of 3-nitrocarbazole in them in admixture with various amounts of 3-nitro-9-(2-oxo)propylcarbazole (from 0 to \(7.44 \cdot 10^{-5}\) M).

Statistical processing of the results was carried out according to /6/.

The relative error from eight determinations, with a confidence probability of 95%, is 4.05%.

It was found that similar results are also obtained for mixtures containing, in addition to 3-nitrocarbazole, its 9-(2-oxy)ethyl or 9-ethyl derivative.

References

1. R. Stewart, J. P. O’Donnell, Canad. J. Chem. Soc., 42, 1681, 1964.
2. R. Eikhman, B. Dukapevich, E. Silaeva. POZh, 6, No. 2, 93, 1959.
3. E. E. Sirotkina. Dissertation. Tomsk, 1964.
4. V. P. Lopatinskii, I. P. Zherebtsov. Author’s certificate 183209, BI, 13, 1966.
5. K. Leidler. Kinetics of Organic Reactions. “Mir,” Moscow, 1969.
6. L. P. Adamovich. Rational Techniques for Compiling Analytical Prescriptions. Publishing House of Kharkov University, 1966.

SYNTHESIS AND PROPERTIES OF PHENYLIODOSO-N-ACETYLAMINOBUTYRATE

S. S. Makarchenko, N. I. Izotova, A. N. Novikov

A representative not described in the literature of the hitherto unknown group of phenyliodosocarboxylates has been obtained—phenyliodoso-N-acetylaminobutyrate. In the products of the thermal decomposition of the latter, iodobenzene, N-acetylaminobutyric acid, phenyl-N-acetylaminobutyrate, and iodine acetylamine were found. Upon decomposition of one mole of phenyliodosoacetylaminobutyrate, 0.4 mole of carbon dioxide is evolved. A scheme is proposed for the reaction of thermal decomposition.

The first representatives of phenyliodosocarboxylates of the formula \(C_6H_5I(OCOR)_2\) were obtained at the end of the last century. Until the 1950s, phenyliodosocarboxylates were exotic substances. Their systematic study began after the discovery of interesting properties—the ability

... toward heterolysis and homolysis of the I–O bond under rather mild conditions.

Until now, carboxylates containing residues of acylated amino acids of the aliphatic series have been unknown. Amino acids of the aliphatic series are important substances, representatives of which are constituents of proteins, medicinal preparations, enzymes, and other biologically active compounds. Therefore, the preparation of their new derivatives is of not only theoretical but also practical interest.

We set ourselves the task of carrying out the synthesis of phenyliodosoacylaminocarboxylates, studying their thermal decomposition, and thereby determining routes for their synthetic use.

Experimental Part

Preparation of $N$-acetyl-$\alpha$-aminobutyrate. Ketene was passed for one hour at room temperature, at a rate of 240–250 bubbles per minute, into a 10% solution of the potassium salt of $\alpha$-aminobutyric acid, prepared from 1.68 g of potassium hydroxide, 15 ml of water, and 3.09 g of $\alpha$-aminobutyric acid. The ketene was prepared by pyrolysis of acetone in a quartz tube 12 mm in diameter and 450 mm long, heated by an electric furnace at 700–750°. After acetylation had been carried out, the solution was evaporated, acidified with hydrochloric acid, cooled to 0°, and the precipitate of $N$-acetyl-$\alpha$-aminobutyric acid was filtered off, washed with small portions of ice water, and then treated with acetone to separate potassium chloride. The acetone solution was filtered and evaporated. The residue was crystallized from a small amount of acetone. The yield of $N$-acetyl-$\alpha$-aminobutyric acid was 60%, m.p. 128°C, literature value 128°C /1/.

Preparation of phenyliodoso-$N$-acetyl-$\alpha$-aminobutyrate.

\[ \mathrm{C_6H_5I(OCOCH_3)_2 + 2\,C_2H_5CH(NHCOCH_3)COOH \longrightarrow} \]

\[ \mathrm{2\,CH_3COOH + C_6H_5I[OCOCH(NHCOCH_3)C_2H_5]_2} \]

The known method of Posaker /2/ and the mixed solvent methanol–chlorobenzene were used. 0.02 mole of acetamino acid, 0.015 mole of phenyliodosoacetate, and 65 ml of solvent were taken.

(15 ml of methanol and 50 ml of chlorobenzene). The reaction temperature was 45–50°, time 1 h. The target product initially separates in the form of an oil. To remove chlorobenzene, it was washed several times with ether and left to crystallize under a layer of ether overnight; then the crystallized product was filtered off, washed with ether and boiling carbon tetrachloride, and dried in a vacuum desiccator. Since the aminocarboxylate obtained was practically insoluble in known solvents, we limited ourselves to washing it. The yield of phenyliodoso-N-acetyl-α-aminobutyrate was 60%, m.p. 102° (decomposition).

In establishing the structure of the aminocarboxylate, the method of synthesis and the results of determining the elemental composition, molecular weight, and IR spectra were taken into account.

Found, %: \(N\) 6.25. \(C_{18}H_{25}JN_2O_6\). Calculated, %: \(N\) 5.90. Calculated molecular weight 492, found 485. The molecular weight was determined according to /3/. The following changes were introduced into the determination procedure. The flask with the potassium iodide solution in an acidic medium was shaken not for 15 min, as required by the procedure, but for 3 min. With more prolonged shaking, less iodine is titrated than is required by calculation, apparently because it reacts with the acylamino acid liberated during decomposition of the sample. Brief shaking is sufficient, since phenyliodosoacylaminocarboxylate vigorously oxidizes hydrogen iodide.

In the IR spectrum there are bands at 1657 (carbonyl group) and 1276 cm\(^{-1}\) (C–O bond), which corresponds to the position of these groups in the IR spectra of known iodosocarboxylates /4/.

On storage under ordinary conditions, phenyliodosoacetylaminobutyrate is noticeably hydrolyzed by atmospheric moisture with formation of iodobenzene and acetylaminobutyric acid. The partially decomposed butyrate can be washed with ether and thus obtained in pure form. When stored in sealed ampoules or stoppered bottles for one month, the butyrate does not decompose noticeably.

Thermal decomposition of phenyliodosoacetylaminobutyrate

Probable schemes of thermal transformation:

\[ \begin{aligned} &\mathrm{C_6H_5I[OCOCH(NHCOCH_3)C_2H_5]_2} \\ &\xrightarrow[\ ]{\mathrm{H,H_2O}} \mathrm{C_6H_5I + 2HOCOCH(NHCOCH_3)C_2H_5} \quad \mathrm{III} \\ &\longrightarrow \mathrm{C_6H_5I + 2\cdot OCOCH(NHCOCH_3)C_2H_5^{\bullet}} \\ &\qquad\qquad \mathrm{IV}\qquad\quad \mathrm{V}\downarrow \\ &\qquad\qquad \mathrm{2CO_2 + [CH(NHCOCH_3)C_2H_5]_2} \\ &\qquad\qquad\qquad\qquad \mathrm{VI} \\[1ex] &\mathrm{C_6H_5I^{+}OCOCH(NHCOCH_3)C_2H_5} + \mathrm{^{-}OCOCH(NHCOCH_3)C_2H_5} \longrightarrow \\ &\qquad\mathrm{VII}\qquad\qquad\qquad\qquad\mathrm{VIII} \\ &\longrightarrow \mathrm{C_6H_5OCOCH(NHCOCH_3)C_2H_5} + \mathrm{IOCOCH(NHCOCH_3)C_2H_5} \\ &\qquad\mathrm{IX}\qquad\qquad\qquad\qquad\mathrm{X}\downarrow \\ &\qquad\qquad\qquad \mathrm{CO_2 + ICH(NHCOCH_3)C_2H_5} \\ &\qquad\qquad\qquad\qquad\mathrm{XI} \end{aligned} \]

The butyrate was heated in a stream of nitrogen in a Wurtz flask: 0.01 mole for 4 minutes at \(100^\circ\). The liquid decomposition products were collected in a receiver after condensation of their vapors in a condenser; the gaseous products (carbon dioxide) were absorbed with a potassium hydroxide solution in Drechsel bottles. In the transformation products, iodobenzene, acetylaminobutyric acid, iodoacylamine (XI), and phenol were found, the latter being detected after hydrolysis of the decomposition products. The latter apparently arose from phenylacylaminobutyrate (IX). Per mole of butyrate, 0.4 mole of carbon dioxide is liberated. Investigation of the thermal-transformation reaction is continuing.

Literature

1. Dictionary of Organic Compounds, vol. I, 564, 1949.
2. K. H. Pausaker, J. Chem. Soc., 1989 (1953).
3. J. F. Shavefkin, H. Saltzman, Anal. Chem., 35, 1428 (1963).
4. R. Bell, K. F. Morgan, J. Chem. Soc., 1209 (1960).

PYROLYSIS OF THE GASOLINE FRACTION OF NORTH-SILGIN GAS CONDENSATE

M. D. Medvedev, S. I. Smolyaninov, A. V. Kravtsov, L. S. Blinova

In Tomsk Oblast, six gas-condensate-type fields have been discovered. The reservoir gas of these fields contains a significant amount of liquid hydrocarbons—gas condensate.