Nojirimycin Based 2,5-Diketopiperazines

2,5-Diketopiperazines were prepared and characterized where one of the amino acids is (2S,3R,4R,5S)-3,4,5-trihydroxypipecolic acid. The protected pipecolic acid was synthesized from a selectively protected deoxynojirimycin derivative. The ring closure to give the diketopiperazines, from the dipeptides, was performed by nucleophilic attack of the amino function of the pipecolic acid moiety onto the carbonyl group of the methyl esters. [GRAPHICS] .