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Synthesis 2004(1): 53-58  
DOI: 10.1055/s-2003-42494
PAPER
© Georg Thieme Verlag Stuttgart · New York

A Convenient Route to O-Glycosyl Lactates via Conjugate Addition to 2-Nitroglycals: Ring Closure to Novel Pyrano[2.3-b][1,4]-oxazines

Ahmed I. Khodairb, Kandasamy Pachamuthua, Richard R. Schmidt*a
a Fachbereich Chemie, Universität Konstanz, Fach M 725, 78457 Konstanz, Germany
Fax: +49(7531)883135; e-Mail: Richard.Schmidt@uni-konstanz.de;
b On leave from the Chemistry Department, Faculty of Education, Tanta University, Kafr El-Sheikh Branch, Kafr El-Sheikh, Egypt
Further Information

Publication History

Received 26 June 2003
Publication Date:
19 November 2003 (online)

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Abstract

Lactate esters d-2a, l-2a, and d-2b could be readily added to 3,4,6-tri-O-benzyl-2-nitro-galactal (1) and 3,4,6-tri-O-benzyl-2-nitro-glucal (4), affording exclusively α- and β-anomers with galacto- and gluco-configuration, respectively. Nitro group reduction to the amino group and ester cleavage led to compounds 6a, 6b, and 7, which can be regarded as dipeptide mimetics. For these compounds the bicyclic pyrano[2.3-b][1,4]-oxazines 8-10 were prepared via ring closure.

Key words

glycal - nitroolefin - Michael additions - glycosides - peptide mimetic - bicyclic systems - azadioxadecalines

11

This compound is commercially available.