Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Patent
1998-11-24
2000-03-28
Krass, Frederick
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
548200, A01N 4378, C07D27754
Patent
active
060432624
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to N-(2,6-dibromo-4-trifluoromethoxyphenyl)-2-methyl-4-trifluoromethyl-5-thia zolecarboxyamide (general name: thifluzamide) with a transformed crystalline form, its preparation method, and a pesticide composition containing thifluzamide as an effective ingredient.
BACKGROUND OF THE INVENTION
Thifluzamide is a compound that has high fungicide activity against rice sheath blight.
Because the time to use a chemical against rice leaf spot withering disease in the cultivation of rice plant is when the rice field is covered with a lesser amount of water, the rate of release and diffusion of effective ingredient affects the controlling effect significantly. However, since water solubility of thifluzamide is extremely low like 1.6 mg/l (20.degree. C.), it is desirable to develop a method that increases the rate of its release in water and improves its efficacy.
DISCLOSURE OF THE INVENTION
The present inventors have discovered that thifluzamide changes its crystalline form when crystallized from a mixture of water and a solution prepared by dissolving the thifluzamide synthesized by a conventional preparation method in organic solvent and that releasability of thifluzamide in water is improved by preparing a pesticide composition using the thifluzamide with transformed crystalline form.
The present invention relates to the following thifluzamide and a process for preparing them. differential scanning calorimeter analysis and having no other peak at less than that temperature. 29.52 by powder X-ray diffraction analysis. admixing the solution of thifluzamide dissolved in an organic solvent with water to crystallize thifluzamide. in an organic solvent into water to crystallize thifluzamide. dissolved in an organic solvent to crystallize thifluzamide. organic solvent at 20.degree. C. is 10 or more parts by weight of water solution. with water in any ratio. solvent selected from the group consisting of alcohols, ketones, ethers, esters, nitrites, N-alkyl pyrrolidones, N,N-dimethyl-formamide or dimethylsulfoxide. effective ingredient. process of (3), (4), (5), (6), (7), or (8) as an effective ingredient.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows powder X-ray diffraction profile of .alpha.-crystalline thifluzamide obtained in the Referential Example.
FIG. 2 shows powder X-ray diffraction profile of .beta.-crystalline thifluzamide obtained in the Example 1.
BEST MODE OF PRACTICING INVENTION
Melting point of thifluzamide is known to be 177.9-178.6.degree. C. (Pesticide Manual, 1994). However, the thifluzamide synthesized in the Referential Example to be stated later shows an endothermic peak in the vicinity of 178.degree. C. by differential scanning calorimetry (DSC), and it shows an additional endothermic peak of 2.0-2.5 cal/g in the vicinity of 161.degree. C. In powder X-ray diffraction analysis, it shows a diffraction profile shown in FIG. 1. Thifluzamide of such crystalline form is called ".alpha.-crystal".
The thifluzamide of the present invention with a transformed crystalline form has a crystalline structure different from the .alpha.-crystalline form as shown by powder X-ray diffraction analysis and DSC analysis of the thifluzamide obtained in Example 1. Specifically, it shows an endothermic peak only in the vicinity of 178.degree. C. by DSC and does not show endothermic peak at less than that temperature. And, in powder X-ray diffraction analysis, the thifluzamide shows a diffraction profile shown in FIG. 2 and shows diffraction peaks at 2.theta.=17.68, 20.04, 23.04, 28.88 and 29.52. Thifluzamide having such crystalline form is called ".beta.-crystal".
The .beta.-crystalline thifluzamide of the present invention is prepared by admixing the solution of thifluzamide dissolved in organic solvent with water to crystallize. The thifluzamide can be obtained by incorporating the solution of thifluzamide dissolved in organic solvent into water or by incorporating water to the solution of thifluzamide dissolved in organic solvent.
Even though there is no
REFERENCES:
patent: 5045554 (1991-09-01), Alt et al.
patent: 5837721 (1998-11-01), Hayakawa et al.
patent: 5886188 (1999-03-01), Bryman et al.
Baba Masatoshi
Hayakawa Norihito
Suwa Norihiro
Yamagishi Kazuhiro
Krass Frederick
Rohm and Haas Company
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