SYNTHESIS OF SUBSTITUTED AMIDES OF 9-AMINOFLUORENE-4-CARBOXYLIC ACID

N. M. SOLDATENKO, G. M. STEPANOVA

(Presented by the scientific seminar of the departments and laboratories of organic synthesis, CTF)

With the aim of finding ways to use coke-chemical phenanthrene in organic synthesis, we previously obtained a series of acyl derivatives of 9-aminofluorene-4-carboxylic acid [1], the zinc and copper salts of which exhibited high insecticidal activity [1].

\[ \mathrm{ArCONH{-}HC} \begin{array}{c} \text{fluorene skeleton} \end{array} \mathrm{{-}COOH} \quad (I); \qquad \mathrm{H_2N{-}HC} \begin{array}{c} \text{fluorene skeleton} \end{array} \mathrm{{-}CONHAr} \quad (II) \]

The aim of the present work was the synthesis of substituted amides of 9-aminofluorene-4-carboxylic acid [2].

The amides obtained give hydrochloride salts readily soluble in water. This may facilitate their use as intestinal poisons. The starting product in the synthesis of the amides was 9-fluorenone-4-carboxylic acid, obtained from ozonolysis products of technical phenanthrene via 2,2′-diphenic acid [2]. The synthesis of the amides was carried out according to the scheme:

\[ \mathrm{ \text{9-fluorenone-4-carboxylic\ acid} \ \longrightarrow\ \text{9-fluorenone-4-carboxylic\ acid\ chloride} \ \longrightarrow\ \text{9-fluorenone-4-carboxanilide} \ \longrightarrow\ \text{oxime} \ \longrightarrow\ \text{9-amino-9H-fluorene-4-carboxanilide} } \]

Experimental Part

1. p-Bromoanilide of 9-fluorenone-4-carboxylic acid. Into a flask equipped with a stirrer and a reflux condenser are charged 8.6 g of 4-bromoaniline, 12.12 g of 9-fluorenone-4-carboxylic acid chloride, and 30 ml of dry xylene. The mixture is heated in an oil bath at a temperature of 130°C for two hours. After cooling, the precipitate is filtered off, washed with benzene and dried, then treated first with dilute hydrochloric acid, then with water and a 10% solution of soda, washed with water, and recrystallized from alcohol.

1. Metachloroanilide of 9-fluorenone-4-carboxylic acid was obtained analogously [1] from 12.12 g of 9-fluorenone-4-carboxylic acid chloride, 5.5 ml of 3-chloroaniline, and 50 ml of dry benzene by heating for one hour at 70°C. Melting point 194–195°C, yield 88–90% of theoretical. Analytical results. Found, %: nitrogen 3.72; chlorine 21.26. C\(_{20}\)H\(_{12}\)O\(_2\)NCl. Calculated, %: nitrogen 3.70; chlorine 21.16.

2. Oxime of parabromoanilide of 9-fluorenone-4-carboxylic acid. In a flask equipped with a reflux condenser, a mixture of 12 g of parabromoanilide of 9-fluorenone-4-carboxylic acid, 6 g of hydroxylamine hydrochloride, 10 g of caustic potash, and 40 ml of 75% ethyl alcohol is boiled for one hour. The solution is cooled and acidified with hydrochloric acid to an acidic reaction. The precipitate is filtered off, washed with water, dried, and recrystallized from alcohol. Melting point 284°C, yield 88–90% of theoretical. Analytical results. Found, %: nitrogen 7.30; bromine 20.50; C\(_{20}\)H\(_{13}\)O\(_2\)N\(_2\)Br. Calculated, %: nitrogen 7.12; bromine 20.35.

3. Oxime of metachloroanilide of 9-fluorenone-4-carboxylic acid was obtained analogously [3] from 10.5 g of metachloroanilide of 9-fluorenone-4-carboxylic acid, 8 g of caustic potash, and 65 ml of 75% ethyl alcohol. Melting point:

Table 1

Dependence of the yield of parabromoanilide of 9-fluorenone-4-carboxylic acid on the reaction temperature
Reaction time 2 hours

Table 2

Dependence of the yield of parabromoanilide of 9-fluorenone-4-carboxylic acid on the reaction time
Reaction temperature 130°C

240°C, yield 80–85% of theoretical. Analytical results. Found, %: nitrogen 7.95; chlorine 9.89. C\(_{20}\)H\(_{13}\)O\(_2\)N\(_2\)Cl. Calculated, %: nitrogen 8.05; chlorine 10.18.

1. Parabromoanilide of 9-aminofluorene-4-carboxylic acid. Into a three-necked flask equipped with a reflux condenser and stirrer are charged 60 ml of glacial acetic acid and 20 ml of water; the mixture is heated on a boiling water bath, and a mixture of 10 g of the oxime of parabromoanilide of 9-fluorenone-4-carboxylic acid and 16 g of zinc dust is added in portions. Heating is continued for another hour. The solution is filtered while hot. The filtrate is cooled and neutralized with a 10% solution of soda to neutral reaction. The precipitate that separates is filtered off, dried, ob—

treated with alcohol while heating. Zinc carbonate is filtered off. The precipitate that separated from the filtrate has a melting point of 220°C. Yield 90% of theoretical. Analysis results. Found, %: nitrogen 7.27; bromine 21.24. \( \mathrm{C}_{20}\mathrm{H}_{15}\mathrm{ON}_{2}\mathrm{Br} \). Calculated, %: nitrogen 7.38; bromine 21.11.

1. Metachloroanilide of 9-aminofluorene-4-carboxylic acid was obtained analogously [5] from 8 g of the oxime of metachloroanilide of 9-fluorenone-4-carboxylic acid, 12 g of zinc dust, 60 ml of glacial acetic acid, and 20 ml of water, with heating for one hour at a bath temperature of 70°C. White crystals with a melting point of 90°C. Yield 80% of theoretical. Analysis results. Found, %: nitrogen 8.46; chlorine 10.82. \( \mathrm{C}_{20}\mathrm{H}_{15}\mathrm{ON}_{2}\mathrm{Cl} \). Calculated, %: nitrogen 8.37; chlorine 10.61.

Conclusions

1. Five substituted amides of 9-aminofluorene-4-carboxylic acid not described in the literature were obtained. Their insecticidal activity was determined.

2. A procedure was developed for the synthesis of parabromoanilide of 9-aminofluorene-4-carboxylic acid.

Literature

1. G. M. Stepnova, P. F. Tabinskaya, A. V. Kovalenok. ZhORKh, 1, no. 6, 1087, 1965.

2. L. P. Kulev, V. A. Salskii, A. K. Lebedev, V. P. Shabrov. ZhVKhO im. D. I. Mendeleeva, 7, 599, 1962.