Method for producing amino acid phosphates

1. A method for producing phosphates of an amino acid or an ester thereof, which comprises allowing a salt of an amino acid or a salt of an amino acid ester to mix and react with phosphoric acids and a basic nitrogen-containing compound in a hydrophilic solvent, wherein an amount of the basic nitrogen-containing compound is from 0.1 mole to 5 moles based on the salt of an amino acid or the salt of an amino acid ester; and

wherein the basic nitrogen-containing compound is pyridines represented by the following formula (3):

(in the formula, R 3 represents a hydrogen atom, a hydrocarbon group having from 1 to 40 carbon atoms which may have a substituent or amino group which may have a substituent), or amines represented by the following formula (4):

NH m R 4 3-m   (4)

(in the formula, m is an integer of from 0 to 2, and R 4 represents a hydrocarbon group having from 1 to 18 carbon atoms which may have a substituent).

2. The method according to claim 1 , wherein the amino acid is selected from α-amino acids, β-amino acids, γ-amino acids and δ-amino acids.

3. The method according to claim 1 or 2 , wherein the salt of an amino acid or the salt of an amino acid ester is a salt of a compound represented by the following formula (1):

R 1 OCOCH 2 CH 2 COCH 2 NH 2   (1)

(in the formula, R 1 represents a hydrogen atom or a hydrocarbon group having from 1 to 40 carbon atoms which may have a substituent).

4. The method according to claim 3 , wherein the phosphoric acids are phosphoric acids represented by the following formula (2):

HOP(O)(OR 2 ) n (OH) 2-n   (2)

(in the formula, R 2 represents a hydrogen atom or a hydrocarbon group having from 1 to 26 carbon atoms which may have a substituent, and n is an integer of 0 to 2).

5. The method according to claim 1 , wherein the salt of an amino acid or the salt of an amino acid ester is first mixed with phosphoric acids, and then the basic nitrogen-containing compound is added to the resulting mixture.