Patent ID: 8183408

Claim:
A process for production of an N-carbamoyl-tert-leucine represented by the general formula (2): wherein, R 1 is a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, or an optionally substituted aryl group having 6 to 12 carbon atoms, comprising a step of mixing tert-leucine with an isocyanic acid compound represented by the general formula (1): R 1 —N═C═O (1) wherein, R 1 is the same as described above, while a pH of the mixture is kept at a range of not less than 8.0 and less than 13.0, wherein the amount of the isocyanic acid compound is not less than 0.9 times by mole and not more than 1.1 times by mole relative to the amount of the tert-leucine.