Synthesis and Study of Alkyl Esters of 9-Oxofluorenoyl-4-amidophosphoric Acid
Abstract Generated abstract
This study describes the synthesis of phosphorus-containing amide derivatives of 9-fluorenone-4-carboxylic acid as potential insecticidal agents. Starting from technical phenanthrene, the authors prepared 9-fluorenone-4-carboxamide, converted it through 9-oxofluorenoyl-4-trichlorophosphazo and the corresponding dichloroanhydride, and then obtained dimethyl, diethyl, and dipropyl esters of 9-oxofluorenoyl-4-amidophosphoric acid. Reaction conditions and yields were examined for key steps, including temperature effects on trichlorophosphazo formation and reagent ratios in ester synthesis. The resulting crystalline esters were characterized by melting points and elemental analysis, and tests against houseflies indicated that the dipropyl ester showed the strongest contact insecticidal activity among the compounds studied.
Full Text
SYNTHESIS AND STUDY OF ALKYL ESTERS OF 9-OXOFLUORENOYL-4-AMIDOPHOSPHORIC ACID
V. V. POLONSKAYA, G. M. STEPANOVA, V. Kh. TAKSIDI
(Presented by the scientific seminar of the departments and laboratories of organic synthesis, KhTF)
We have previously described the syntheses of substituted amides of 9-fluorenone-4-carboxylic acid [1]. Some of the compounds obtained exhibited insecticidal activity. In order to find new insecticides, several additional amides of 9-fluorenone-4-carboxylic acid were synthesized, having as substituents in the amide group residues containing phosphorus.
These substances were obtained from 9-fluorenone-4-carboxylic acid amide via 9-oxofluorenoyl-4-trichlorophosphazo and the dichloroanhydride of 9-oxofluorenoyl-4-amidophosphoric acid according to the scheme:
\[ \text{9-fluorenone-4-carboxamide} \xrightarrow{\mathrm{PCl_5}} \text{9-oxofluorenoyl-4-trichlorophosphazo} \xrightarrow[\mathrm{C_2H_5OH}]{\mathrm{HCOOH}} \text{dichloroanhydride of 9-oxofluorenoyl-4-amidophosphoric acid} \xrightarrow{\mathrm{2AlkOH}} \text{dialkyl ester of 9-oxofluorenoyl-4-amidophosphoric acid} \]
In the scheme, the final product has the structure:
\[ \mathrm{9\text{-}oxofluorenoyl\text{-}4\text{-}CONH\text{-}P(=O)(OAlk)_2} \]
Technical phenanthrene was used as the starting material; it was subjected to ozonolysis [2]. On the basis of the ozonolysis product of phenanthrene, dimethoxy peroxide, diphenic acid was synthesized, and from it 9-fluorenone-4-carboxylic acid [3]. The amide of 9-fluorenone-4-carboxylic acid was obtained from its acid chloride under the action of ammonia.
Dialkyl esters of 9-oxofluorenoyl-4-amidophosphoric acid are crystalline yellow substances, insoluble in water, sparingly soluble in ether, and readily soluble in benzene, dioxane, and acetone. The compounds obtained were tested for insecticidal activity on the housefly. As a contact poison, the dipropyl ester of 9-oxofluorenoyl-4-amidophosphoric acid showed the best results.
Experimental Part
9-Oxofluorenoyl-4-trichlorophosphazo. 10.4 g of phosphorus pentachloride, 11.15 g of 9-fluorenone-4-carboxylic acid amide, and 100 ml of dry benzene are placed in a flask fitted with a reflux condenser. The flask is immersed in a water bath at a temperature of 65–70°C. After 15 minutes the reaction is complete. After cooling, pale-yellow needles precipitate; these are washed with a small amount of benzene and dried in a vacuum desiccator. Melting point 135°C, yield 78–80% of theoretical.
Dichloride anhydride of 9-oxofluorenoyl-4-amidophosphoric acid. To a solution of 7.16 g of trichlorophosphazo-9-oxofluorenoyl-4 in 40 ml of benzene, 0.6 ml of anhydrous formic acid is added slowly, dropwise. The reaction proceeds with self-heating. The dichloride anhydride precipitates; it is filtered off, washed with benzene, and dried in a vacuum desiccator. The melting point of the technical product is 207–209°C, yield 96–98% of theoretical. After recrystallization from dioxane the melting point is 210°C. Analysis. Found, %: C 49.27; H 2.65. Calculated, %: C 49.12; H 2.67.
Table 1
Dependence of the yield of trichlorophosphazo-9-oxofluorenoyl-4 on temperature
Reaction time 15 minutes
| Reaction temperature, °C | Yield, % | Melting temperature, °C |
|---|---|---|
| 50 | 67 | 132–133 |
| 55 | 69 | 133–134.5 |
| 60 | 76 | 134–135 |
| 65 | 78 | 134–135 |
| 70 | 77 | 134–135 |
| 75 | 74 | 134–135 |
| 80 | 65 | 133–135 |
| 85 | 60 | 133–135 |
| 90 | 42 | 133–135 |
Alkyl esters of 9-oxofluorenoyl-4-amidophosphoric acid. To a cooled solution of 0.04 g-mole of sodium alcoholate in 15 ml of the corresponding alcohol, 3.4 g (0.01 g-mole) of the dichloride anhydride of 9-oxofluorenoyl-4-amidophosphoric acid is added in small portions. After all the dichloride anhydride has been added, the mixture is boiled for 15 minutes; the reflux condenser is replaced by a direct condenser, and the excess alcohol is distilled off. The residue is dissolved in water and the solution is filtered. The filtrate is acidified with hydrochloric acid; in this process the dialkyl ester precipitates. The characteristics of the obtained alkyl esters of 9-oxofluorenoyl-4-amidophosphoric acid are given in Table 2.
Table 2
| Name of ester | M.p., °C | Yield, % | Content, % carbon found | Content, % carbon calculated | Content, % hydrogen found | Content, % hydrogen calculated |
|---|---|---|---|---|---|---|
| Methyl | 220 | 66 | 58.43 | 58.01 | 4.33 | 4.23 |
| Ethyl | 183 | 58 | 60.58 | 60.32 | 4.82 | 4.98 |
| Propyl | 138 | 49 | 63.08 | 62.40 | 5.76 | 5.69 |
Table 3
Dependence of the yield of the diethyl ester of 9-oxofluorenoyl-4-amidophosphoric acid on the ratio of the reacting substances
| Number of g-moles dichloride anhydride | Number of g-moles sodium ethylate | Reaction time, min | Reaction temperature, °C | Yield, % | M.p. of technical product, °C |
|---|---|---|---|---|---|
| 0.01 | 0.02 | 30 | 80 | 50 | 166–168 |
| 0.01 | 0.03 | 30 | 80 | 68.5 | 173–175 |
| 0.01 | 0.04 | 30 | 80 | 73 | 177–180 |
| 0.01 | 0.05 | 30 | 80 | 72.5 | 177–180 |
| 0.01 | 0.06 | 30 | 80 | 73 | 179–180 |
Conclusions
- Conditions were developed for the synthesis of the dimethyl, diethyl, and dipropyl esters of 9-oxofluorenoyl-4-amidophosphoric acid.
- A procedure was developed for the synthesis of the intermediate product for obtaining these esters—9-oxofluorenoyl-4-trichlorophosphazo.
- The insecticidal activity of the esters obtained was determined.
Literature
- L. P. Kulev, G. M. Stepnova, A. V. Kovalenok, P. F. Tabinskaya. Izvestiya SO AN SSSR, 12, 128, 1962.
- L. P. Kulev, V. A. Salskii, A. K. Lebedev, V. P. Shabrov. ZhVKhO im. D. I. Mendeleeva, 7, 599, 1962.
- C. Graebe. Ch. Aubin, Lieb. Ann., 247, 257 (1888).