| 摘要 |
The invention relates to beta-alaninamides of general formula (I), wherein: R1 represents hydrogen or C1-C6 alkyl which is optionally substituted by hydroxy, amino, carboxy, carbamoyl, methylmercapto, guanidino, or by optionally substituted aryl or heteroaryl; R2 represents hydrogen or R1 and R2, together, form a group of formula -(CH2)n, wherein n represents 3 or 4, and; R3 represents hydrogen, a negative charge compensated for by an equivalent of an inorganic or organic cation or represents C1-C6 alkyl. The beta-alaninamides are produced without using an amino protective group by reacting the corresponding alpha-amino acid or the corresponding alpha-amino acid ester with a cyanoacetic acid to form a cyanoacetic acid amide and by a subsequent catalytic hydrogenation. The method is particularly suited for producing carnosine (betaalanyl-L-histidine, R1=imidazol-4-yl-methyl, R2=R3=H), a naturally occurring dipeptide, which is used as a food additive having an antioxidant effect.
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