SYNTHESIS OF β-D-MANNOSE 1,2-ORTHOACETATES

Canadian Science Publishing - Tập 43 Số 7 - Trang 1918-1923 - 1965
Mytosk Mazurek, Arthur S. Perlin

Tóm tắt

Synthesis of 3,4,6-tri-O-acetyl-β-D-mannopyranose 1,2-orthoacetates (I) from 2,3,4,6-tetra-O-acetyl-α-D-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 stereoselective orthoester synthesis than does the silver-catalyzed reaction, leading to formation of the OR-exo-diastereoisomer almost exclusively.

Từ khóa


Tài liệu tham khảo

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Canadian Science Publishing

Tập 43 Số 7

1918-1923

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