SYNTHESIS OF BETA-D-MANNOSE 1,2ORTHOACETATES,
Abstract
Synthesis of 3,4,6-tri-O-acetyl-beta-D-mannopyranose 1,2-orthoacetates (I) from 2,3,4,6-tetra-O-acetyl-alphaD-mannopyranosyl bromide (II) and various alcohols in the presence of pyridine and substituted pyridines is described. 2,6-Lutidine is a particularly effective acid acceptor in these condensations, and the use of chloroform as a diluent is advantageous. The lutidine-buffered system has afforded a good yield of orthoacetate (I) with several alcohols that barely react with II in the presence of silver ion; this difference is attributed to the dominance of side reactions under the latter conditions. The N-bases also promote a more highly stereo-selective orthoester synthesis than does the silver-catalyzed reaction, leading to formation of the OR-exo-diastereoisomer almost exclusively. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 04, 1965
- Accession Number
- AD0618809
Entities
People
- A. S. Perlin
- Micah Mazurek
Organizations
- National Research Council Canada