Constituents of microbial iron chelators. Alternate syntheses of .delta.-N-hydroxy-L-ornithine derivatives and applications to the synthesis of rhodotorulic acid
The total synthesis of NBRI16716B (2), a naturally occurring modulator of tumor-stroma interactions, was successfully achieved. Using this synthetic route, a dehydroxy analogue (21) and a derivative lacking the 5-hydroxy-3-methylpentenoyl side chain (22) became accessible. A preliminary structure-activityrelationshipstudy to unveil the structural requirements for selective inhibition of tumor cells
Facile syntheses of rhodotorulic acid, isolated from Rhodotorula pilimanae as a siderophore, and its 1,4-dimethylated derivative have been achieved by microwave-assisted cyclization of the corresponding dipeptide precursors.