| 摘要 |
PROBLEM TO BE SOLVED: To provide a 2β-chloromethyl-2α-methylpenam-3α-carboxylic acid benzhydryl ester (CMPB) crystal having excellent stability. SOLUTION: This crystal is, for example, characterized by an X-ray powder diffraction pattern given by copper radiant rays which are passed through a monochromator and have aλof 1.5418Å. The crystal is, for example, produced by (A) concentrating a CMPB-containing solution, (B) subjecting the obtained concentrated solution to column chromatography, (C) concentrating the CMPB-containing fraction, and (D) dissolving the obtained CMPB-containing concentrate in an ether solvent and then adding a hydrocarbon solvent to the CMPB-containing solution, so as to make the CMPB crystal precipitated. COPYRIGHT: (C)2005,JPO&NCIPI
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