Original scientific paper

The Azomethine Imine Route to Guanidines. Total Synthesis of (+)-Saxitoxin

Michael J. Martinelli ; Hall-Atwater Laboratories, Wesleyan University, Middletown ,Connecticut, USA 06457
Allen D. Brownstein ; Hall-Atwater Laboratories, Wesleyan University, Middletown ,Connecticut, USA 06457
Peter A. Jacobi ; Hall-Atwater Laboratories, Wesleyan University, Middletown ,Connecticut, USA 06457
Slovenka Polanc ; Department of Chemistry, E. Kardelj University 61000 Ljubljana, Jugoslavija

Abstract

Azomethine imines may be readily generated through the
interaction of aldehyde aeetals with earboxylie acid hydrazides.
These reaetions are most highly favored in pollar aprotie solvents
and aeid eatalysis is required. With suitably funetionalized
hydrazides these substanees undergo a faeile intramolecular addition
to give fused-ring pyrazolidine derivati ves. As a part of these
studies, (± )-Saxitoxin (7), the paralytie agent of the Alaska butter
elam Saxidomas giganteus, has been synthesized in a totally stereospecific fashion through a sequenee involving as the key steps:
(a) intramolecular 1,3-dipolar addition of an azomethine imine to
a 2-imidazolone; (b) reductive cleavage of the resulting pyrazolidine
ring followed by intramoleeular acylation; and (c) final elaboration of a bis-pseudourea to the requisite guanidine functionality.

Keywords

Hrčak ID:

177593

URI

https://hrcak.srce.hr/177593

Publication date:

16.5.1986.

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