| 摘要 |
PURPOSE:To obtain the crystal of the titled compound having excellent crystal habits such as separability, in high yield, by regulating the initial concentration of an aqueous solution of L-alpha-aspartyl-L-phenylalanine methyl ester, and crystallizing the compound under cooling without stirring. CONSTITUTION:The initial concentration of an aqueous solution of L-alpha-aspartyl- L-phenylalanine methyl ester (hereinafter abbreviated as APM) is adjusted to about >=10g per 1 liter of the solvent in which the precipitated solid phase exists after cooling. The solution is cooled by thermal conduction without applying the force to flow, e.g. mechanical agitation so as to transform the whole solution to a pseudo-solid phase having sherbet-like appearance. After formation of the pseudo-solid phase, the APM is crystallized, if necessary by breaking the supersaturation by cooling under forced flow. The dimension of the short axis of the crystal obtained by the crystallization under pseudo-solid phase condition is more than 5-10 times that of the crystal obtained by conventional process, and the present process is also economically advantageous. |
