1189587-59-4Relevant academic research and scientific papers
Synthetic studies of cyclic peptides stephanotic acid methyl ester, celogentin C, and moroidin
Li, Lei,Hu, Weimin,Jia, Yanxing
, p. 7753 - 7762 (2014)
An account of the total synthesis of stephanotic acid methyl ester and celogentin C is presented. The present synthesis features a tandem asymmetric Michael addition/bromination sequence for the synthesis of leucine-tryptophan moiety, and an oxidative coupling reaction to form the tryptophan-imidazole linkage. Moreover, the total synthesis of moroidin had also been studied, and three different synthetic strategies for the construction of the right-hand ring of moroidin were studied.
Total synthesis of celogentin C by stereoselective C-H activation
Feng, Yiqing,Chen, Gong
supporting information; experimental part, p. 958 - 961 (2010/06/11)
(Figure Presented) A total gent: Inspired by the biosynthesis of celogentin C, a highly stereoselective and efficient palladium-catalyzed C-H functionalization strategy is employed to construct the key Leu-Trp linkage of this bicyclic compound. A streamlined synthesis is completed in 23 steps from simple amino acid building blocks.
Total synthesis of the antimitotic bicyclic peptide celogentin C
Ma, Bing,Banerjee, Biplab,Litvinov, Dmitry N.,He, Liwen,Castle, Steven L.
supporting information; experimental part, p. 1159 - 1171 (2010/04/01)
An account of the total synthesis of celogentin C is presented. A right-to-left synthetic approach to this bicyclic octapeptide was unsuccessful due to an inability to elaborate derivatives of the right-hand ring. In the course of these efforts, it was discovered that the mild Braslau modification of the McFadyen-Stevens reaction offers a useful method of reducing recalcitrant esters to aldehydes. A leftto-right synthetic strategy was then examined. The unusual Leu-Trp side-chain cross-link present in the left-hand macrocycle was fashioned via a three-step sequence comprised of an intermolecular Knoevenagel condensation, a radical conjugate addition, and a SmI2-mediated nitro reduction. A subsequent macrolactamization provided the desired ring system. The high yield and concise nature of the left-hand ring synthesis offset the modest diastereoselectivity of the radical conjugate addition. Formation of the Trp-His sidechain linkage characteristic of the right-hand ring was then accomplished by means of an indole-imidazole oxidative coupling. Notably, Pro-OBn was required as an additive in this reaction. Detailed mechanistic investigations indicated that Pro-OBn moderates the concentration of NCS in the reaction mixture, thereby minimizing the production of an undesired dichlorinated byproduct. The natural product was obtained after macrolactamization and deprotection. The chemical shifts of the imidazole hydrogen atoms exhibited significant dependence on temperature, concentration, and pH. Antitumor screening indicated that celogentin C inhibits the growth of some cancer cell lines.
Stereocontrolled and efficient total synthesis of (-)-stephanotic acid methyl ester and (-)-celogentin C
Hu, Weimin,Zhang, Fengying,Xu, Zhengren,Liu, Qiang,Cui, Yuxin,Jia, Yanxing
supporting information; experimental part, p. 956 - 959 (2010/06/15)
(Figure Presented) A highly stereocontrolled and efficient total synthesis of (-)-stephanotlc acid methyl ester and (-)-celogentin C was accomplished In longest linear 14 steps (4.6% overall yield) and In 20 steps (1.6% overall yield) from L-tryptophan, respectively. Highlights of the synthesis include a tandem asymmetric Michael addition/bromination/azidation strategy for a ready access to the leucine-tryptophan moiety (Leu-Trp linkage) and an oxidative coupling reaction to form the indole-imidazole linkage.
