Crystal forms of 6-bromo-3-hydroxy-2-pyrazinecarboxamide
AssigneeFUJIFILM Toyama Chemical Co., Ltd.
InventorsTetsuro Uchida, Sayuri Uehara, Takayoshi Tsuzuki, Yusuke Okubo, Yuta Kobayashi, Yu Koseki
Life of this patent
Estimating the term…
Abstract
The purpose of the present invention is to provide a method for producing 6-bromo-3-hydroxy-2-pyrazinecarboxamide in which the content ratio of impurities is reduced. This production method includes a step of obtaining 6-bromo-3-hydroxy-2-pyrazinecarboxamide crystal having diffraction angles expressed in degrees 2θ of 5.5, 20.1, 23.7, 26.7, 27.5, and 28.1° and/or diffraction angles expressed in degrees 2θ of 7.1, 21.4, 25.2, 25.7, 27.1, and 28.8° in powder X-ray diffraction.
Claims14
A type-A crystal of 6-bromo-3-hydroxy-2-pyrazinecarboxamide having powder X-ray diffraction angles (2θ) of 5.5°, 20.1°, 23.7°, 26.7°, 27.5° and 28.1°.
A method for producing a type-A crystal of 6-bromo-3-hydroxy-2-pyrazinecarboxamide, wherein the method comprises:
- (1) adding anhydrous 3-hydroxy-2-pyrazinecarboxamide having powder X-ray diffraction angles (2θ) of 11.9°, 13.2°, 23.9°, and 26.7° to N,N-dimethylformamide to form a suspension;
- (2) reacting the suspension formed in the adding above with bromine to produce a mixture;
- and
- (3) obtaining a type-A crystal of 6-bromo-3-hydroxy-2-pyrazinecarboxamide having powder X-ray diffraction angles (2θ) of 5.5°, 20.1°, 23.7°, 26.7°, 27.5° and 28.1°.
A method for producing a type-A crystal of 6-bromo-3-hydroxy-2-pyrazinecarboxamide, wherein the method comprises:
- (1) adding a type-B crystal of 6-bromo-3-hydroxy-2-pyrazinecarboxamide having powder X-ray diffraction angles (2θ) of 7.1°, 21.4°, 25.2°, 25.7°, 27.1° and 28.8° to N,N-dimethylformamide in the presence of activated carbon to form a suspension;
- (2) filtering the suspension formed in the adding above;
- (3) washing the filter cake obtained in the filtering above with N,N-dimethylformamide;
- (4) adding water to the combined filtrates formed in the filtering and the washing above to form a mixture;
- and
- (5) obtaining a type-A crystal of 6-bromo-3-hydroxy-2-pyrazinecarboxamide having powder X-ray diffraction angles (2θ) of 5.5°, 20.1°, 23.7°, 26.7°, 27.5° and 28.1°.
Dependencies are inferred from the claim text.