METHOD FOR SYNTHESIZING 1,1-DIAMINO-2,2-DINITROETHYLENE (FOX-7) OR A SALT THEREOF

Abstract

In a method for synthesizing 1,1-diamino-2,2-dinitroethylene (FOX-7) or a salt thereof, an isourea derivative cation, which consists of a C(NH.sub.2)(NH.sub.2.sup.+) radical and a nucleofugal leaving group bonded to the carbon atom of the C(NH.sub.2) (NH.sub.2.sup.+) radical, is reacted with a dinitromethane anion. The reaction of the isourea derivative cation with the dinitromethane anion takes place in a solution.

Claims

1. A method for synthesizing 1,1-diamino-2,2-dinitroethylene (FOX-7) or a salt thereof, which comprises the step of: reacting an isourea derivative cation, which consists of a C(NH.sub.2)(NH.sub.2.sup.+) radical and a nucleofugal leaving group bonded to a carbon atom of the C(NH.sub.2) (NH.sub.2.sup.+) radical, with a dinitromethane anion.

2. The method according to claim 1, which further comprises performing the reacting of the isourea derivative cation with the dinitromethane anion in a polar aprotic solvent.

3. The method according to claim 2, which further comprises using dimethylformamide (DMF) as the polar aprotic solvent.

4. The method according to claim 1, which comprises selecting the nucleofugal leaving group from the group consisting of an O-alkyl, O-methyl, O-ethyl, O-propyl, O-butyl, O-pentyl, triazolyl, halide, chloride, carbonyl halide, carbonyl chloride, nonaflate, trifluoromethanesulphate, sulphonate, halosulphonate, fluorosulphonate, tosyl, mesyl, diazonium, oxonium, quaternary ammonium compound, ester, acid anhydride, nitrate, phosphate, organic ester, ammonium, phenol, alcohol and a carboxylic radical.

5. The method according to claim 1, which further comprises selecting the isourea derivative cation from the group consisting of a chloroformamidinium ion and a triazole carboxamidine ion.

6. The method according to claim 1, wherein the isourea derivative cation is associated with a sulphate, hydrogen sulphate, acetate, halide, or chloride, as a counterion.

7. The method according to claim 5, wherein the isourea derivative cation is associated with chloride as a counterion.

8. The method according to claim 1, wherein the dinitromethane anion is associated with a potassium ion or ammonium ion as a counterion.

9. The method according to claim 1, which further comprises converting a 1,1-diamino-2,2-dinitroethylene anion formed in a synthesis into the 1,1-diamino-2,2-dinitroethylene by lowering a pH of a solution containing the 1,1-diamino-2,2-dinitroethylene anion.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0019] FIG. 1 shows a reaction scheme of a synthesis of FOX-7 from nitration of a nitrogen heterocycle with subsequent hydrolysis to an end product;

[0020] FIG. 2 shows a reaction scheme of a synthesis of FOX-7 from nitration of 2-methyl-2-methoxyimidazoledione;

[0021] FIG. 3 shows a reaction scheme of a synthesis of FOX-7 from nitration of 2-methyl-4,6-pyrimidinedione;

[0022] FIG. 4 shows a reaction scheme of the synthesis of FOX-7 from O-alkylated isourea salt;

[0023] FIG. 5 shows a reaction scheme of the synthesis of KFOX-7 from chloroformamidinium hydrochloride; and

[0024] FIG. 6 shows a reaction scheme of the synthesis of KFOX-7 from triazole carboxamidine hydrochloride.

DETAILED DESCRIPTION OF THE INVENTION

[0025] To synthesize FOX-7 from O-alkylated isourea salt according to FIG. 4, 490 mg (3.4 mmol) of potassium dinitromethanate and 419 mg (3.4 mmol) of O-methylisourea sulphate are dissolved successively with stirring in 50 ml of water at 70° C. in a 100 ml round-bottomed flask. The solution is then further stirred at 70° C. for one hour. The white precipitate formed is separated off by filtration. From the remaining solution, the solvent is slowly distilled off in the rotary evaporator. The FOX-7 product precipitates here as a yellow precipitate. For further purification, the product is dissolved in acetonitrile/methanol 30/70 and subjected to chromatography on a 20 cm long silica column with acetonitrile/methanol 30/70 as eluent mixture. From the fraction comprising the product, the solvent is distilled off by means of a rotary evaporator.

[0026] A 1H-NMR spectrum, a 13C-NMR spectrum and a mass spectrum of the reaction product and a KFOX-7 reference show that FOX-7 is indeed present in the reaction. The results of the analysis of the reaction product compared to the KFOX-7 reference are reported in Table 1 below:

TABLE-US-00001 TABLE 1 Reaction Analysis product KFOX-7 reference 1H-NMR 8.4 ppm 8.8 ppm (s) broad (400 MHz) (s) broad (corresponds to FOX-7) 13C-NMR 158.43 ppm 158.41 ppm singlet (400 MHz) singlet Mass 149 m/z 149 m/z spectrum (ESI)

[0027] To synthesize KFOX-7 in accordance with the reaction scheme according to FIG. 5, 73 mg (0.5 mmol) of potassium dinitromethanate is dissolved in 20 ml of DMF at 60° C. in a 50 ml glass beaker and 58 mg (0.5 mmol) of chloroformamidinium hydrochloride are added. The solution was stirred at 60° C. for 2 hours and then allowed to cool to room temperature with stirring. After distilling off the solvent, the residue was dried in an explosion-proof drying oven at 50° C. and then measured thermoanalytically by dynamic differential scanning calorimetry (DSC) and also by IR, NMR and mass spectroscopy. The result is shown in Table 2 below:

TABLE-US-00002 TABLE 2 Analysis Reaction product K-FOX-7 reference 1H-NMR 8.54 ppm (s) 8.88 ppm (s) (400 MHz) (corresponds to FOX-7) 13C-NMR 158.4 ppm 158.4 ppm (400 MHz) (KFOX-7) Mass spectrum 149 m/z 148 m/z (=M + 1 peak FOX-7) DSC 230° C. 220-250° C. (FOX-7)

[0028] Comparison with the KFOX-7 reference shows that the reaction product comprises KFOX-7.

[0029] To synthesize KFOX-7 according to the reaction scheme shown in FIG. 6, 980 mg of potassium dinitromethanate (6.8 mmol) are dissolved in 10 ml of distilled water in a 100 ml round-bottomed flask. To this is added 1 g of 1H-1,2,4-triazole-1-carboxamidine hydrochloride (6.8 mmol). Immediately after the addition, the pH is adjusted with 20% KOH solution to pH 11 to 12 and the temperature is increased to 50° C. The solution is stirred overnight at 50° C. The solvent is then distilled off in the rotary evaporator. A yellow residue remains which is washed in a filter frit three times with 20 ml of isopropanol each time to remove triazole and KOH. Determination of the decomposition temperature by DSC gives a value of 222° C., which is in agreement with the value of the KFOX-7 reference. A 13C-NMR spectrum shows a peak for KFOX-7 which is identical to the KFOX-7 peak of a reference sample. A mass spectrometric investigation also shows agreement of the reaction product with the KFOX-7 reference. The results are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Analysis Reaction product KFOX-7 reference 13C-NMR 158.4 ppm singlet 158.41 ppm singlet Mass spectrum 149 m/z 149 m/z DSC 228° C. 228° C.

[0030] Comparison with the KFOX-7 reference shows that the reaction product comprises KFOX-7.

[0031] In the working examples, it is also possible to use ammonium dinitromethanate in place of potassium dinitromethanate.