“…For example, the carbonyl group of LA undergoes the Knoop ± Oesterlin reductive amination. 77 This reaction is catalysed by Co, Ni and Pd and gives either the corresponding amino acids 33, 78 or 5-methyl-2-pyrrolidone derivatives 34 as a result of cyclodehydration, depending on whether the carboxy group of LA is protected or not. 79,80 The amides formed by the reaction of LA with various amines are attractive not only because of their biological activity, 81 but also because of their ability for cyclisation.…”