Abstract: A method for producing an alkylamine derivative having a urea bond represented by formula (I), or a salt thereof, comprises the following steps (a) and (b), step (a): and step (b): deprotecting as necessary the reaction product obtained in step (a). The production method suitable for industrialization of the alkylamine derivative having a urea bond represented by formula (I), which is a compound highly useful as an agent having CaSR agonist effects is provided.

Abstract: A method for preparing a phenylalanine derivative having a quinazoline-dione ring represented by the following formula (1) or a pharmaceutically acceptable salt thereof, comprising the following steps (a), (b) and (c): (a) reacting an acyl phenylalanine derivative represented by the following formula (2): with a carbonyl group-introducing reagent and a specific anthranilic acid derivative to thus form the corresponding carboxy-asymmetric urea derivative; (b) converting the carboxy-asymmetric urea derivative into the corresponding quinazoline-dione derivative in the presence of a carboxyl group-activating agent: (c) if desired, substituting an N-alkyl group for the hydrogen atom bonded to the nitrogen atom present in the quinazoline-dione ring of the quinazoline-dione derivative using an N-alkylation agent and then deprotecting the resulting product, when the substituent R3? which is a group corresponding to R3 is protected.

Abstract: Crystals of isopropyl ester of N-(2,6-dichlorobenzoyl)-4-[6-(methylamino)methyl-1-methyl-2,4-dioxo-1,4-dihydroquinazoline-3(2H)-yl]-L-phenylalanine hydrochloride: are useful as ?4 integrin inhibitors.

Abstract: A method for preparing a phenylalanine derivative having a quinazoline-dione ring represented by the following formula (1) or a pharmaceutically acceptable salt thereof, comprising the following steps (a), (b) and (c): (a) reacting an acyl phenylalanine derivative represented by the following formula (2): with a carbonyl group-introducing reagent and a specific anthranilic acid derivative to thus form the corresponding carboxy-asymmetric urea derivative; (b) converting the carboxy-asymmetric urea derivative into the corresponding quinazoline-dione derivative in the presence of a carboxyl group-activating agent: (c) if desired, substituting an N-alkyl group for the hydrogen atom bonded to the nitrogen atom present in the quinazoline-dione ring of the quinazoline-dione derivative using an N-alkylation agent and then deprotecting the resulting product, when the substituent R3? which is a group corresponding to R3 is protected.

Abstract: The present invention releates to a method for preparing a phenylalanine compound having a quinazoline-dione ring represented by the following formula (1) or a pharmaceutically acceptable salt thereof: where R1-R4 are defined herein. The method involves reacting a specified acyl phenylalanine compound with a carbonyl group-introducing reagent and a specified anthranilic acid compound to form a carboxy-asymmetric urea compound which is converted to a quinazoline-dione compound in the presence of a carboxyl group-activating agent.

Abstract: Crystals of isopropyl ester of N-(2,6-dichlorobenzoyl)-4-[6-(methylamino)methyl-1-methyl-2,4-dioxo-1,4-dihydroquinazoline-3(2H)-yl]-L-phenylalanine hydrochloride are useful as ?4 integrin inhibitors.

Abstract: Crystals of isopropyl ester of N-(2,6-dichlorobenzoyl)-4-[6-(methylamino)methyl-1-methyl-2,4-dioxo-1,4-dihydroquinazoline-3(2H)-yl]-L-phenylalanine hydrochloride are useful as ?4 integrin inhibitors.

Abstract: A method for preparing a phenylalanine derivative having a quinazoline-dione ring represented by the following formula (1) or a pharmaceutically acceptable salt thereof, comprising the following steps (a), (b) and (c): (a) reacting an acyl phenylalanine derivative represented by the following formula (2): with a carbonyl group-introducing reagent and a specific anthranilic acid derivative to thus form the corresponding carboxy-asymmetric urea derivative; (b) converting the carboxy-asymmetric urea derivative into the corresponding quinazoline-dione derivative in the presence of a carboxyl group-activating agent: (c) if desired, substituting an N-alkyl group for the hydrogen atom bonded to the nitrogen atom present in the quinazoline-dione ring of the quinazoline-dione derivative using an N-alkylation agent and then deprotecting the resulting product, when the substituent R3? which is a group corresponding to R3 is protected.

Abstract: The present invention discloses crystals of phenylalanine derivatives which have a specific structural formula, and particularly crystals which are easy to be used; crystals excellent in preservation stability, humidity resistance or solubility; and crystals which can be manufactured on the industrial scale. The present invention also discloses the production method thereof and use thereof, and particularly the use thereof as an active ingredient of pharmaceutical compositions.