Total synthesis and biological evaluation of tamandarin B analogues
(Chemical Equation Presented) Tamandarins A and B are a class of marine natural cyclodepsipeptides with structures and biological activities closely related to those of the didemnins. The easier synthetic access to tamandarins accelerates the preparation of new macrocyclic derivatives of this family of antitumor, antiviral, and immunosuppressive compounds. The optimization of the previously reported synthetic route to tamandarins by changing the macrolactamization site from Nst1 and Thr6 to Pro 4 and N,O-Me2Tyr5 residues led to a significant improvement in the reaction yield. Using this new synthetic approach, four new macrocyclic analogues of tamandarin B were prepared and evaluated for anticancer activity. These results provide further insight into the structure-activity relationship of the tamandarins and didemnins.
Adrio, Javier,Cuevas, Carmen,Manzanares, Ignacio,Joullie, Madeleine M.
Preparation of phosphoamino acid derivatives with acid stable O-phosphono-protection for the Boc-mode solid-phase synthesis of phosphopeptides
Boc-phosphoamino acid derivatives with O-[di(4-nitrobenzyl)- or dicyclohexylphosphono]-protection were prepared for application to the Boc-mode solid-phase synthesis of phosphopeptides. These protecting groups are both stable to TFA, but removable with a combination of trifluoromethanesulfonic acid and methylthiobenzene in TFA. Of these derivatives, N(α)-Boc-O-(dicyclohexylphosphono)serine and N(α)-Boc-O-(dicyclohexylphosphono)threonine were obtained as crystalline compounds to be favorably utilized as starting materials for solid-phase synthesis using an automated peptide synthesizer. On the other hand, N(α)-Boc-O-(dicyclohexylphosphono)tyrosine and all of the O-[di(4-nitrobenzyl)]phosphono derivatives were prepared as crystalline cyclohexylammonium or dicyclohexylammonium salts.
Wakamiya,Saruta,Yasuoka,Kusumoto
p. 2699 - 2703
(2007/10/03)
More Articles about upstream products of 120219-31-0