PATEL RAKESH BHULABHAI (IN)
SHROFF JAIDEV RAJNIKANT (AE)
SHROFF VIKRAM RAJNIKANT (AE)
| WO2017193619A1 | 2017-11-16 |
| CN103980192A | 2014-08-13 | |||
| US20060154825A1 | 2006-07-13 | |||
| CN104920366A | 2015-09-23 | |||
| CN104478797A | 2015-04-01 | |||
| US7087239B2 | 2006-08-08 | |||
| US20110054183A1 | 2011-03-03 | |||
| GB2536979A | 2016-10-05 | |||
| GB2539022A | 2016-12-07 | |||
| US7087239B2 | 2006-08-08 | |||
| US7501384B2 | 2009-03-10 |
| CLAIMS 1. A process for the preparation of boscalid anhydrate form Ϊ, the process comprising crystallizing boscalid from a haiogenated hydrocarbon solvent 2. The process as claimed in claim 1, wherein said process comprises crystallizing a mixture of boscalid anhydrate form I and boscalid anhydrate form II from a haiogenated hydrocarbon solvent. 3. The process as claimed in claim 1 or claim 2, wherein said process comprises crystallizing boscalid anhydrate form II from a haiogenated hydrocarbon solvent. 4. The process as claimed in any one of the preceding claims, wherein the process comprises crystallizing boscalid from a mixture of haiogenated hydrocarbons, and optionally water. 5. The process as claimed in any one of the preceding claims, wherein the haiogenated hydrocarbon solvent is selected from haiogenated lower hydrocarbons containing C-s to Ce carbon atoms. 6. The process as claimed in any one of the preceding claims wherein the haiogenated hydrocarbon solvent is selected from dichloromethane, dich!oroethane, chloroform, and chlorobenzene. 7. A process for the preparation of boscalid anhydrate form I, the process comprising: (a) dissolving boscalid in a hatogenated hydrocarbon solvent, optionally in presence of water, at or above room temperature; (b) cooling and stirring the solution at a first predetermined speed; and (c) effecting crystallization. 8. The process as claimed in claim 7 comprising dissolving boscalid in a haiogenatec! hydrocarbon solvent, optionally in presence of water, at a temperature from about 25° to about 120° C. 9. The process as claimed in claim 7, wherein said stirring in step (b) is performed at a predetermined speed of 400-700 rpm, preferably at a speed of 450-650 rpm. 10. The process as claimed in claim 7, wherein in step (b), the solution of boscalid is cooled to a temperature which varies from about 20T to about 50° C. 11. The process as claimed in claim 10, wherein cooling of boscalid solution is carried out in a time period of 15 minutes to 2 hours. 12. The process as claimed in any of the claims 7 - 11 , wherein said crystallization is effected at a temperature from about -15eC to about 30° C, 13. The process as claimed in any of the claims 7 - 12, wherein said crystallization is effected by sudden cooling, 14. The process as claimed in any of the claims 7 - 12,. wherein said crystallization is carried out in a time period of 15 minutes to 2 hours. 15. The process as claimed in any of the claims 7 - 14, wherein said crystall ization is initiated by seeding the solution with boscaiid anhydrate form I 16. A process for the preparation of boscaiid anhydrate form ΙΪ, the process comprising crystallizing boscaiid from a haiogenated hydrocarbon solvent. 17. The process as claimed in claim 16, wherein said process comprises crystallizing a mixture of boscaiid anhydrate form I and boscaiid anhydrate form II from a haiogenated hydrocarbon solvent. 18. The process as claimed in claim 15 or claim 17, wherein saici process comprises crystallizing boscaiid anhydrate form: II from a haiogenated hydrocarbon solvent. 19. The process as claimed in any one of the preceding claims, wherein the process comprises crystallizing boscaiid from a mixture of haiogenated hydrocarbons, and optionally water, 20. The process as clai med in any one of the preceding claims, wherein the haiogenated hydrocarbon solvent is selected from haiogenated lower hydrocarbons containi ng Ci to Ce carbon atoms. 21, The process as claimed in any one of the preceding claims wherein the haiogenated hydrocarbon solvent is selected from clichloromethane, dich!oroethane, chloroform, and chiorobenzene. 22. A process for the preparation of boscaiid anhydrate form Π, the process comprising: (a) dissolving boscaiid in a halogenated hydrocarbon solvent, optionally in presence of water, at or above room temperature; (b) cooling and stirring the solution at a second predetermined speed; and (c) effecting crystallization. The process as claimed in claim 22 comprising dissolving boscaiid in a halogenated hydrocarbon solvent, optionally in presence of water, at a temperature from about 25° to about 120° C, 24. The process as claimed in claim 22, wherein said stirring in step (b) is performed at a second predetermined speed of 40-130 rpm, preferabiy at a speed of 50-100 rpm. 25. The process as claimed in claim 22, wherein in step (b), the solution of boscaiid is cooled to a temperature which varies from about 20°C to about 50° C 26. The process as claimed in claim 25, wherein cooling of boscaiid solution is carried out in a time period of 2 hours to 4 hours. 27. The process as claimed in any of the claims 22 - 26, wherein said crystallization is effected at a temperature from about -15°C to about 30° C. 28. The process as claimed in any of the claims 22 - 27, wherein said crystallization is effected by gradual cooling, 29. The process as claimed m any of the claims 22 - 27, wherein said crystallization is carried out in a time period of 1 hour to 4 hours. 30. The process as claimed in any of the claims 22 - 29, wherein said crystallization is initiated by seeding the solution with faoscaiid anhydrate form ΪΙ. |
Technical field of the invention:
The present invention relates to a novel process for preparation of boscalid an hydrate form I and boscalid anhydrate form II.
Background of the invention:
Solid state compounds exist in different physical forms such as crystalline (regular geometric lattice), and amorphous forms {irregular geometric lattice). This phenomenon is called polymorphism. It is derived from the greek word "polus" means "many" and "morph" means "shape". Thus it is defined as the ability of a substance to exist in two or more crystalline forms that have different arrangements or conformations of the molecules in the crystal lattice.
Polymorphic forms of a substance can have different chemical and physical properties, including melting point, chemical reactivity, solubility, optical, electrical and mechanical properties,, vapor pressure, stability, and density.
2~Chloro-N-(4'-chloiObiphenyl:-Z-yl)nicotinamide is a succinate dehydrogenase inhibitor (SDHI) fungicide commonly known as boscalid. Boscalid is known to exist in three crystalline forms- boscalid anhydrate form i, boscalid anhydrate form II, boscalid rnonohydrate form and an amorphous form. Boscalid anhydrate form I is used as starting materia! for preparing boscalid rnonohydrate form which is suitable for making SC formulations. Further form Ϊ is used for preparing boscalid anhydrate form II which is found to be suitable for making solid formulations. US7087239B2 discloses boscalid monohydrate form I and its preparation from an organic solvent selected from dioxane, tetrahydrofuran, dimethylformamide, N- methylpyrrolidone, benzene, toluene and xylene.
US7501384B2 discloses boscalid anhydrate form ii and its preparation from a polar protic solvent such as an alcohol, glycol, ketone, ether, ester, amide or dimethyl sulfoxide or a mixture thereof.
These processes available in the prior art require the use of large volumes of expensive solvents. Moreover, these processes do not give satisfactory yields, Hence there is a need to develop an economicai process to prepare boscalid anhydrate form I and boscaiid anhydrate form II.
Objects of the Invention
Accordingly, it is an object of the present invention to prepare boscalid anhydrate form I in substantially pure form.
It is an object of the present invention to prepare boscalid anhydrate form 11 in substantially pure form.
It is an object of the present invention to develop an economical process to produce boscalid anhydrate forms I and II.
It is an object of the present invention to develop a process to obtain boscalid anhydrate forms I and II in better yield. Summary of the invention
A process for preparing boscaiid anhydrate form I comprising crystallizing boscalid from a halogenated hydrocarbon solvent.
A process for preparing boscalid anhydrate form I comprising: a) dissolving boscaiid in a halogenated hydrocarbon solvent at or above room temperature;
b) cooling and stirring the solution at a first predetermined speed; and c) effecting crystallization. A process for preparing boscaiid anhydrate form Π comprising crystallizing boscaiid from a halogenated hydrocarbon solvent.
A process for preparing boscaiid anhydrate form II comprising: a} dissolving boscaiid in a halogenated hydrocarbon solvent at or above room temperature;
b) cooling and stirring the solution at a second predetermined speed; and c) effecting crystallization.
Detailed description of the invention
The inventors of the present invention surprisingly found out that substantially pure boscaiid anhydrate form I and boscaiid anhydrate form II can be selectively prepared by crystallizing from a halogenated hydrocarbon solvent under selective stirring and cooling conditions.
Accordingly,, the present invention provides a process for the preparation of boscaiid anhydrate form I by crystallizing boscaiid from a halogenated hydrocarbon solvent. Further, the present invention also provides a process for the preparation of boscaiid anhydrate form II by crystallizing boscaiid from a halogenated hydrocarbon solvent.
Boscaiid anhydrate form I refers to monociinic boscaiid anhydrate modification I with melting point ' 144-145° C Boscaiid anhydrate form II refers to monoc!inic boscaiid anhydrate modification II with melting point 147-148° C. in an embodiment of the present invention, boscaiid anhydrate form I is prepared by process comprising: a) dissolving boscaiid in a halogenated hydrocarbon solvent at or above room temperature;
b) cooling and stirring the solution at a first predetermined speed; and c) effecting crystallization.
In another embodiment of the present invention, boscaiid anhydrate form I is prepared by process comprising: a) dissolving boscaiid in a halogenated hydrocarbon solvent, optionally in presence of water, at or above room temperature;
b) cooling and stirring the solution at a first predetermined speed; and c) effecting crystallization. Various methods for preparing boscaiid of step a) are known in literature.
In an embodiment of the present invention,, boscaiid of step a) comprises a mixture of boscaiid anhydrate form Ϊ and boscaiid anhydrate form II.
Therefore, in this embodiment, the present invention provides a process for preparing boscaiid anhydrate form I comprising crystallizing a mixture of boscaiid anhydrate form I and boscaiid anhydrate form II from a halogenated hydrocarbon solvent.
In yet another embodiment of the present invention, boscaiid of step a) comprises boscaiid anhydrate form II. Therefore, in this embodiment, the present invention provides a process for preparing boscalid anhydrate form I comprising crystallizing boscalid anhydrate form H from a halogenated hydrocarbon solvent.
According to another ernbodiment the solvents of step a) comprises a mixture of halogenated hydrocarbons.
In another embodiment, the solvents of step a) comprises a mixture of halogenated hydrocarbons and water.
In an embodiment of the present invention, in step a} the halogenated hydrocarbon solvent is selected from halogenated lower hydrocarbons containing G to Cs carbon atoms. in a preferred embodiment of the present invention, the halogenated hydrocarbon solvent is selected from but not limited to dichioromethane, dichloroethane, chloroform, and chlorobenzene.
In an embodiment of the present invention, in step a), boscalid is dissolved at temperature from about 25° to about 120° C. in an embodiment stirring of step b) is performed at a predetermined speed of 400-700 rpm, preferably at a speed of 450-650 rpm.
In an ernbodiment of the present invention, in step b), solution of boscalid is cooled to a temperature which varies from about 20°C to about 50° C, In an embodiment of the present invention, step b), cooling of boscalid solution is carried out in a time period of 15 minutes to 2 hours.
According to an embodiment of the present invention, in step c), the crystallization is effected at a temperature which varies from about -15°C to about 30° C. According to an embodiment of the present invention, in step c), the crystallization is effected by sudden coo!ing.
In another embodiment of the present invention, in step c), the crystallization of boscaiid anhydrate form I is carried out in a time period of 15 minutes to 2 hours. According to one embodiment of the present invention, in step c), the crystallization is initiated by seeding the solution with boscaiid anhydrate form I. in an embodiment of the present invention the boscaiid anhydrate form I crystals are isolated by filtration.
In an embodiment, the chemical procedure which may be used to prepare boscaiid anhydrate form I is not particularly limiting and may be carried out by a skilled technician as per the standard conventional procedure as long as the criticality of the selected solvent, stirring speed and cooling condition is maintained.
The present invention further provides a process for preparation of boscaiid anhydrate form II. In an embodiment of the present invention, boscaiid anhydrate form II is prepared by a process comprising the following steps: a) dissolving boscaiid in a haiogenated hydrocarbon solvent at or above room temperature;
b) cooling and stirring the solution at a predetermined speed; and c) effecting crystallization
In an embodiment of the present invention, boscaiid anhydrate form II is prepared by a process comprising the following steps: a) dissolving boscaiid in a halogenated hydrocarbon solvent optionally in presence of water at or above room temperature;
b) cooling and stirring the solution at a predetermined speed; and
c) effecting crystallization In another embodiment of the present invention, boscalid of step a) comprises a mixture of boscalid an hydrate form I and boscalid anhydrate form II.
In yet another embodiment of the present invention, boscalid of step a) comprises boscalid anhydrate form I,
According to another embodiment, solvents of step a) comprises a mixture of halogenated hydrocarbons.
In another embodiment, solvents of step a) comprises a mixture of halogenated hydrocarbon solvents and water.
In an embodiment of the present invention, in step a) the halogenated hydrocarbon solvent is selected from halogenated lower hydrocarbons containing Cj to Cs carbon atoms.
In a preferred embodiment of the present invention, the halogenated hydrocarbon solvent is selected from but not limited to dichloromethane, dich!oroethane, chloroform and chloroberrzene.
In an embodiment of the present invention, in step a), boscalid is dissolved at temperature from about 25°C to about 120°C
In an embodiment, stirring of step b) is performed at a predetermined speed of 40- 130 rpm, preferably at a speed of 50-100 rpm. In an embodiment of the present invention, in step b), solution of boscalid is cooled to a temperature which varies from about 20°C to about 50 a C.
In an embodiment of the present invention, in step b), cooling of boscalid solution is carried out in a time period of about 2 hours to about 4 hours. According to another embodiment of the present invention, in step c) the crystaiiization is effected at a temperature which varies from about -1 S°C to about 30°C.
According to an embodiment of the present invention, in step c), the crystallization is effected by gradual cooling. in another embodiment of the present invention, in step c), the crystaiiization of boscalid anhydrate form II is carried out in a time period of about 1 hour to about 4 hours.
According to another embodiment of the present invention, the crystaiiization is effected by seeding the solution with boscalid anhydrate form II. In an embodiment of the present invention the boscalid anhydrate crystal form Π are isolated by filtration.
In an embodiment, the chemica! procedure which may be used to prepare boscalid anhydrate form II is not particularly limiting and may be carried out by a skilled technician as per the standard conventional procedure as long as the criticality of the selected solvent, stirring speed and cooling condition is maintained.
Thus, the present invention provides a process for the preparation of boscalid anhydrate form Ϊ and/or boscalid anhydrate form Π selectively by crystallizing boscalid from at least one ha!ogenated hydrocarbon solvent, optionally in admixture with water. In an embodiment,, the selectivity between boscalid anhydrate form I and boscalid anhydrate form II is achieved by selecting the above- described stirring and cooling conditions, which are different for boscalid anhydrate form I and boscalid anhydrate form II, to selectively lead to either substantially pure boscalid anhydrate form I or substantially pure boscalid anhydrate form II,
The invention shall now be described with reference to the following specific examples, It should be noted that the examples appended below illustrate rather than limit the invention and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the present invention.
Examples
The following examples described below are to illustrate the embodiments of the present invention and are not limiting the scope of the present invention. The product has been characterized using DSC (Differential Scanning Caloiimetry) and FT-IR.
Example 1: Preparation of boscalid
To a stirred solution of 4-chlorobiphenyi-2-yi-amine (154.0 g. 0,805 mol) in dichloroethane (812.0 g) was added triethylamine (96.0 g, 0.950 mol) at room temperature. The reaction mixture was cooled to 10 B C and 2-chloronicotinyl chloride (179.0 g, 1.017 mol) in dichloroethane (268.0 g) was drop wise added to it for 5-6 h. The reaction mixture' was refluxed for 1 h. The reaction was cooled to 30° C and water (278.0 g) was added to it. The mixture was heated to 60-70° C for 30 min and then stirred for 15 minutes, The mixture was cooled to room temperature and aqueous layer was separated. The organic layer was washed with 5% aqueous sodium hydroxide solution followed by water. The organic layer was dried on sodium sulphate.
Example 2: Preparation of bosca!id anhydrate form I
In a reaction assembly, the organic layer (obtained from Example 1) was diluted with dichioroethane (1326.0 g) and stirred above room temperature. The solution was stirred at 450-600 rpm and cooled to 25-35 " C in 1 hour. After crystal formation was observed., the solution was suddenly cooled to -10° to 5 C C. The crystals were stirred at same temperature for 1 hour. The crystalline solid was filtered and dried to obtain 230.0 g of boscalid anhydrate form I. Melting point: 145.07 °C
IP. (cm -1 ): 923, 1313, 1652
Example 3: Preparation of boscalid anhydrate form II
In a reaction assembly, the organic layer (obtained from Example 1) was diluted with dichioroethane (1326.0 g) and stirred above room temperature. The solution was stirred at 50-100 rpm and gradually cooled to 35-45° C in 3 hours. After crystals formation were observed, it was maintained at same temperature for 1 h. The crystals were gradually cooled to -10" to 5° C and stirred at same temperature for 1 hour. The crystalline solid was filtered and dried to obtain 237.0 g of boscalid anhydrate form II. Melting point 147.57 °C
IR (cm -1 ); 867, 917, 1677
Example 4: Preparation of boscalid anhydrate form I from a mixture of boscalid anhydrate form Ϊ and boscalid anhydrate form II A mixture of boscaiid anhydrate form 1 and boscaiid anhydrate form II (250.0 g, 0.728 mo I) was charged in a reaction assembly. To this mixture was added dichloromethane (2250,0 g) and stirred at room temperature till dissolution. The solution was stirred at 450-600 rpm and cooled to 25-35° C in 1 hour. After crystal formation was observed, the solution was suddenly cooled to -10° to 5 a C. The crystals were stirred at same temperature for 1 hour. The crystalline solid was filtered and dried to obtain 200.0 g of boscaiid anhydrate form I.
Melting point: 145.09 °C
IR (cm-1): 924, 1313, 1651 Example 5: Preparation of boscaiid anhydrate form II from mixture of boscaiid anhydrate form I and form II
A mixture of boscaiid anhydrate form I and boscaiid anhydrate form II (250.0 g, 0.728 mo!) was charged in a reaction assembly. To this mixture was added dichloroethane (1000.0 g) and stirred above room temperature till dissolution. The solution was stirred at 50- 100 rpm and gradually cooled to 35-45° C in 3 hours and maintained at same temperature for 1 h. After crystals formation were observed, it was maintained at same temperature for 1 h. The crystals were gradually cooled to - 10° to 5° C and stirred for 1 hour. The crystalline solid was filtered and dried to obtain 225.0 g of boscaiid anhydrate form II. Melting point: 147.50 °C
IR (cm -1 ): 867, 916, 1675
Example 6: Preparation of boscaiid anhydrate form I from boscaiid anhydrate form II A mixture of boscalid anhydrate form Π (250.0 g, 0.72S mol) in chiorobenzene (2000.0 g) was stirred above room temperature till dissolution. The solution was stirred at 450-600 rpm and cooled to 25-35" C in 1 hour. After crystal formation was observed, the solution was suddenly cooled to -10° to 5°C. The crystals were stirred at same temperature for 30 minutes to 1 hour. The crystalline solid was filtered and dried to obtain 227.0 g of boscalid anhydrate form I.
Melting point: 145.06 °C
IR (cm- 1 ): 922, 1314, 1651
Example 7: Preparation of boscalid anhydrate form ΪΪ from boscalid anhydrate form 1
A mixture of boscalid anhydrate form 3 (250.0 g, 0.728 mol) in chloroform (1000.0 g) and water (7.0 g) was stirred above room temperature till dissolution. The solution was stirred at 50-100 rpm: and gradually cooled to 35-45° C in 3 hours. After crystals formation were observed, it was maintained at same temperature for 1 h. The crystals were gradually cooled to -10° to 5° C in 1 to 2 hours and stirred at same temperature for 30 minutes to 1 hour. The crystalline solid was filtered and dried to obtain 228,0 g of boscalid anhydrate form II.
Melting point 147.48 °C
IR fcm- 1 ): 869, 916 . , 1676 Vv'hiie the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods with the scope and spirit of the invention.