Crystalline modification of fipronil

Abstract

The present invention relates to a novel crystalline modification of fipronil, to a process for the preparation of the same, to pesticidal and parasiticidal mixtures and compositions comprising said crystalline modification and to their use for combating pests and parasites.

Claims

1. A synergistic pesticidal or parasiticidal mixture comprising, as active components, a solid fipronil comprising at least 98% by weight of crystalline modification V fipronil showing, in an X-ray powder diffractogram recorded using Cu-K radiation at 25 C., at least 3 of the following reflexes:
2=10.30.2(1)
2=11.10.2(2)
2=13.00.2(3)
2=16.20.2(4)
2=20.30.2(5)
2=31.50.2(6) and one or more other pesticidal or parasiticidal compound selected from the group consisting of: bifenthrin, alpha-cypermethrin, dinotefuran, thiamethoxam, abamectin; an anthranilamide compound of formula .sup.3 ##STR00005## wherein A.sup.1 is CH.sub.3; X is N; Y is Cl; Y is hydrogen; B.sup.1 is Cl; B.sup.2 is Br; and R.sup.B is CH.sub.3; and pyraclostrobin; wherein fipronil and the one or more other pesticidal or parasiticidal compound are present in a ratio of 500:1 to 1:100.

2. The mixture of claim 1 further comprising pesticidally or parasiticidally acceptable carriers and/or auxiliaries.

3. The composition according to claim 2 in the form of an aqueous suspension concentrate.

4. The composition according to claim 2 in the form of water-dispersible granules.

5. The composition according to claim 2 in the form of a water-dispersible powder.

6. The mixture of claim 1, wherein the crystalline modification V of fipronil is present in a triclinic system having the centrosymmetric space group P-1.

7. The mixture of claim 1, wherein the crystalline modification V fipronil shows, in an X-ray powder diffractogram recorded using Cu-K radiation at 25 C., at least 5 of the refluxes.

8. The mixture of claim 1, wherein the one or more other pesticidal or parasiticidal compound is pyraclostrobin.

9. The mixture of claim 1, wherein fipronil and pyraclostrobin are present in a ratio of 100:1 to 1:100.

10. The mixture of claim 1, wherein the one or more pesticidal or parasiticidal compound is selected from bifenthrin, alpha-cypermethrin, dinotefuran, thiamethoxam, abamectin, the anthranilamide compounds of formula .sup.3 ##STR00006## wherein A.sup.1 is CH.sub.3; X is N; Y is Cl; Y is hydrogen; B.sup.1 is Cl; B.sup.2 is Br; and R.sup.B is CH.sub.3.

11. The mixture of claim 1, wherein fipronil and the one or more pesticidal or parasiticidal compound are present in a ratio of 20:1 to 1:50.

12. The mixture of claim 1, wherein wherein the one or more other pesticidal or parasiticidal compounds is bifenthrin.

13. The mixture of claim 1, wherein wherein the one or more other pesticidal or parasiticidal compounds is alphacypermethrin.

14. The mixture of claim 1, wherein wherein the one or more other pesticidal or parasiticidal compounds is dinotefuran.

15. The mixture of claim 1, wherein wherein the one or more other pesticidal or parasiticidal compounds is thiamethoxam.

16. The mixture of claim 1, wherein wherein the one or more other pesticidal or parasiticidal compounds is abamectin.

Description

(1) The figure and examples below serve to illustrate the invention and are not to be understood as limiting it.

(2) FIG. 1: X-ray powder diffractogram of modification V

(3) FIG. 2: Differential scanning calorimetry thermogram of modification V

(4) FIG. 3: X-ray powder diffractograms of two mixtures of modifications I and V

PREPARATION EXAMPLES

(5) All preparation procedures below were conducted with two samples of solid fipronil as starting materials which were obtained according to procedures as described in WO 01/30760, with final crystallization of the product from a solvent mixture of monochlorobenzene/ethanole (% by weight of ethanol at crystallization start: 13%) at temperatures of 70 C. to 35 C. This solid form in X-ray powder diffractogram studies proved to be crystalline fipronil of a mixture of several crystalline modifications. This mixture has been characterized to consist of crystalline modification I and crystalline modifications V, as for the first time identified and described in a co-pending application. A least squares refinement with the Topas program with simulated X-ray powder diffractogram patterns from single crystal data of form I and form V shows that in these two example samples, the percentage of form I varies from 30% to 70%. X-ray powder diffractograms of the two samples are shown in FIG. 3.

(6) Irrespective of the sample of solid fipronil used as starting material, the crystallization procedures given in the examples given below gave the same inventive modification V. The solvates modification II and F-ST are preferably not used for evaporation crystallisations.

Example 1

(7) Preparation of modification V by crystallization from acetonitrile 1 g of crystalline fipronil having a chemical purity of about 96% by weight was dissolved in 25 g of acetonitrile at 75 to 81 C. under reflux. The solution was kept at this temperature while the solvent was slowly evaporated with a gentle flow of inert N.sub.2 gas. The solvent was left to evaporate for 3 days, after which the sample was cooled to 20 C. to 25 C. and the obtained dry crystalline material was filtered from some residual solvent on a paper filter by using vacuum. Crystallization yield >95%, melting point: 202 C. The material obtained has the X-ray powder diffractogram shown in FIG. 1 with the reflexes listed in Table 2 below.

Example 3

(8) Preparation of modification V by crystallization from dimethylsulfoxide 0.5 g of crystalline fipronil having a chemical purity of about 96% by weight was dissolved in 10 ml of DMSO at 138 to 142 C. in a round bottomed flask. The solution was kept at this temperature while the solvent was slowly evaporated with a gentle flow of inert N.sub.2 gas. The solvent was left to evaporate for about 15 hours, after which the sample was cooled to 20 C. to 25 C. and the obtained crystalline material was filtered from some residual solvent on a paper filter by using vacuum. Crystallization yield >85%, melting point: 202.5 C. The material obtained has the X-ray powder diffractogram shown in FIG. 1 with the reflexes listed in Table 2 below.

(9) TABLE-US-00003 TABLE 2 2- and d-values of modification V 2 () d () 10.3 0.2 8.55 0.1 11.1 0.2 7.94 0.07 13.1 0.2 6.78 0.05 16.3 0.2 5.43 0.05 20.4 0.2 4.35 0.05 31.6 0.2 2.83 0.03
Analysis:

(10) The picture of the X-ray powder diffractogram displayed in FIG. 1 was taken using a Siemens D-5000 diffractometer (manufacturer: Bruker AXS) in reflection geometry in the range from 2=2-60 with increments of 0.02 using Cu-K radiation at 25 C.

(11) The single crystal X-ray diffraction data was collected on a Bruker AXS CCD Detector using graphite Cu.sub.K radiation. The structure was solved by using direct methods, refined, and expanded by using Fourier techniques with the SHELX software package (G. M. Sheldrick, SHELX-97, Universitt Gttingen, 1997). Absorption correction was performed with SADABS software

(12) The 2 values found were used to calculate the stated interplanar spacing d. In FIG. 1. the intensity of the peaks (y-axis: linear intensity in counts) is plotted versus the 2 angle (x-axis in degrees 2).

(13) Heats of fusion indicated here refer to values determined by Differential scanning calorimetry (DSC) on a Mettler DSC 823 in air atmosphere with a heating rate of 5 K/min in the range from +30 to +230 C.

(14) Melting points indicated herein refer to values determined on a Mettler hot stage microscope and represent equilibrium melting points.

(15) DSC was performed on a Mettler Toledo DSC 823 module in air atmosphere. Crystals taken from the mother liquor were blotted dry on filter paper and place in crimped but vented aluminum sample pans for the DCS experiment. The sample size in each case was 5 to 10 mg. The temperature range was typically 30 C. to 230 C. at a heating rate of 5 K/min.