18928-00-2Relevant articles and documents
Synthesis and structure-activity relationship study of NBRI16716B, an antitumor natural product
Abe, Hikaru,Sakashita, Chiharu,Kawada, Manabu,Nomoto, Akio,Watanabe, Takumi,Shibasaki, Masakatsu
, p. 463 - 468 (2015)
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-activity relationship study to unveil the structural requirements for selective inhibition of tumor cells cocultured with stromal cells revealed that both of the hydroxamate structures of 2 are indispensable, whereas the 5-hydroxy- 3-methylpentenoyl side chain is not essential.
Constituents of Microbial Iron Chelators. Alternate Syntheses of δ-N-Hydroxy-L-ornithine Derivatives and Applications to the Synthesis of Rhodotorulic Acid
Lee, Byung Hyun,Gerfen, Gary J.,Miller, Marvin J.
, p. 2418 - 2423 (2007/10/02)
δ-N-Hydroxy-L-ornithine derivatives, the key constituents of several microbial iron chelators, have been prepared from protected forms of L-glutamic acid.Reduction of α-tert-butyl N-Boc-glutamate (3) provided α-tert-butyl L-N-Boc-δ-hydroxynorvaline (4).Direct treatment of 4 with Cbz-O-benzylhydroxylamine (5) or trOC-O-benzylhydroxylamine (6) gave the protected δ-N-hydroxyornithine derivatives 7 and 8, respectively. δ-N-Deprotection followed by acetylation provided α-tert-butyl-L-N-Boc-δ-N-acetyl-δ-N-benzyloxyornithine (9).Appropriate α-amino and α-carboxyl deprotections of 8 and 9 provided derivatives of δ-N-hydroxy-L-ornithine suitable for the synthesis of rhodotorulic acid (24) by two routes.The first route employed conventional peptide synthesis methods.The second synthesis or rhodotorulic acid involved the direct dimerization of Leuch's anhydrides 25 and 26 derived from the δ-N-acetyl- and δ-N-trOC-δ-N-benzyloxyornithines 11 and 16.
