Patent ID: 7238830

Claim:
An N-alkylaspartyl dipeptide ester compound, and salts thereof, represented by the formula (1): wherein R 1 , R 2 , R 3 , R 4 and R 5 are independent from each other, selected from the group consisting of a hydrogen atom, a hydroxyl group, an alkoxy group having 1 to 3 carbon atoms, an alkyl group having 1 to 3 carbon atoms and a hydroxy alkyloxy group having two or three carbon atoms, and R 1 and R 2 , or R 2 and R 3 , optionally, form a methylene dioxy group, and R 4 and R 5 , and R 1 or R 3 which do not form the methylene dioxy group are defined as above; R 6 , R 7 , R 8 , R 9 and R 10 are independent from each other, a hydrogen atom or an alkyl group with 1 to 3 carbon atoms; and optionally, two of R 6 , R 7 , R 8 , R 9 and R 10 may combine to form an alkylene group with 1 to 5 carbon atoms, and R 6 , R 7 , R 8 , R 9 and R 10 which do not form the alkylene group with 1 to 5 carbon atoms are defined as above; R 11 is selected from the group consisting of a hydrogen atom, a benzyl group, a p-hydroxy benzyl group, a cyclohexyl methyl group, a phenyl group, a cyclohexyl group, a phenyl ethyl group and a cyclohexyl ethyl group; R 12 is selected from the group consisting of a hydrogen atom and an alkyl group with 1 to 3 carbon atoms; and R 13 is selected from the group consisting of alkyl groups with 1 to 4 carbon atoms; with the proviso that the following are excluded: where R 6 , R 7 , R 8 , R 9 and R 10 are hydrogen atoms at the same time, where R 6 is a methyl group, R 1 , R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 and R 12 are a hydrogen atom at the same time and R 11 is a benzyl group or a p-hydroxy benzyl group, at the same time; and where R 2 or R 4 is a methoxy group, R 3 is a hydroxyl group, R 10 is a methyl group, R 1 , R 4 or R 2 , R 5 , R 6 , R 7 , R 8 and R 9 are hydrogen atoms at the same time, and R 11 is a benzyl group or a p-hydroxy benzyl group.