| abstract |
The invention relates to beta -alaninamides of general formula (I), wherein: R<1> represents hydrogen or C1-C6 alkyl which is optionally substituted by hydroxy, amino, carboxy, carbamoyl, methylmercapto, guanidino, or by optionally substituted aryl or heteroaryl; R<2> represents hydrogen or R<1> and R<2>, together, form a group of formula -(CH2)n , wherein n represents 3 or 4, and; R<3> 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 ( beta -alanyl-L-histidine, R<1> = imidazol-4-yl-methyl, R<2> = R<3> = H), a naturally occurring dipeptide, which is used as a food additive having an antioxidant effect. |