Nonracemizable Isocyanoacetates for Multicomponent Reactions
摘要:
Chiral ortho esters of a-isocyano acids were synthesized from commercially available Cbz-protected alpha-amino acids. These compounds are stable toward racemization in the Ugi 4CC in contrast to known esters of alpha-isocyano acids. Applying them in Ugi 4CC with subsequent deprotection gives access to dipeptides with preserved configuration at the C-terminal amino acid.
Peptide Macrocyclization Assisted by Traceless Turn Inducers Derived from Ugi Peptide Ligation with Cleavable and Resin-Linked Amines
作者:Alfredo R. Puentes、Micjel C. Morejón、Daniel G. Rivera、Ludger A. Wessjohann
DOI:10.1021/acs.orglett.7b01761
日期:2017.8.4
multicomponent approach enabling the installation of turn-inducing moieties that facilitate the macrocyclization of short and medium-size oligopeptides is described. The strategy comprises the Ugi ligation of peptide carboxylic acids and isocyanopeptides in the presence of aldehydes and acid or photolabile amines followed by cyclization and cleavage of the backbone N-substituents to render canonical
Efficient synthesis of tetrazole derivatives of cytisine using the azido-Ugi reaction
作者:Danil P. Zarezin、Adil M. Kabylda、Valentina I. Vinogradova、Pavel V. Dorovatovskii、Victor N. Khrustalev、Valentine G. Nenajdenko
DOI:10.1016/j.tet.2018.06.045
日期:2018.8
The azido-Ugi reaction with natural alkaloid cytisine was investigated. It was demonstrated that the reaction could be performed with various carbonyls (both aldehydes and ketones) and isocyanides. The transformation proceeded under mild conditions in methanol using TMSN3 as a source of hydrazoic acid to give target tetrazole derivatives of cytisine in up to 98% yield. The diastereoselectivity of this