1-HYDROXY-3-AMINO-2-PIPERIDONE (DELTA-N-HYDROXYCYCLOORNITHINE) DERIVATIVES - KEY INTERMEDIATES FOR THE SYNTHESIS OF HYDROXAMATE-BASED SIDEROPHORES

Several routes for the synthesis of -N-(benzyloxy)cycloornithine (2) from glutamic acid derived starting materials are described. Efficient methods were developed for the synthesis of glutamic acid 7-semialdehyde and 5-hydroxynorvaline derivatives as key substrates for preparation of N-hydroxyornithine analogues. Thus, the best approaches to the synthesis of 2 were: (1) reductive cyclization of an N-hydroxysuccinimide ester of the O-benzyloxime 4 of a-amino-protected glutamic acid 7-semialdehyde 5 and (2) cyclization of the N- (benzyloxy)amide of 6-bromonorvaline (7). © 1990, American Chemical Society. All rights reserved.