Total syntheses of hyacinthacine A2 and 7-deoxycasuarine by cycloaddition to a carbohydrate derived nitrone
摘要:
Practical syntheses of nitrone 8 by two different approaches from sugars are reported. Its use as a versatile intermediate in highly selective 1,3-dipolar cycloaddition reactions constitutes the key step for novel total syntheses of hyacinthacine A(2) (3) and 7-deoxycasuarine (20) by simple transformations of a common isoxazolidine adduct. (C) 2003 Elsevier Science Ltd. All rights reserved.
Synthesis, Biological Evaluation and Docking Studies of Casuarine Analogues: Effects of Structural Modifications at Ring B on Inhibitory Activity Towards Glucoamylase
We report the total synthesis of a series of pyrrolizidine analogues of casuarine (1) and their 6-O-alpha-glucoside derivatives. The synthetic strategy is based on a totally regio- and stereoselective 1,3-dipolar cycloaddition of suitably substituted alkenes and a carbohydrate-based nitrone. We also report the evaluation of the biological activity of casuarine and its derivatives towards a wide range
transformation of the reaction products allowed the synthesis of four new tetrahydroxylated indolizidines. Their activity as glycosidase inhibitors was evaluated against a panel of commercially available glycosidases. The specificity of inhibitory activity against amyloglucosidase and α-mannosidases depends on the configuration at C-2 of the indolizidine moiety.
Practical syntheses of nitrone 8 by two different approaches from sugars are reported. Its use as a versatile intermediate in highly selective 1,3-dipolar cycloaddition reactions constitutes the key step for novel total syntheses of hyacinthacine A(2) (3) and 7-deoxycasuarine (20) by simple transformations of a common isoxazolidine adduct. (C) 2003 Elsevier Science Ltd. All rights reserved.
Synthesis and glycosidase inhibition of C-7 modified casuarine derivatives
Abstract A series of C-7 modified analogues of casuarine have been synthesized from sugar-derived nitrone and assayed against various glycosidases. Introduction of C-7 aminomethyl or amide group led to sharp decrease of the inhibitory activities.