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Convenient Glycoside Synthesis of Amino Sugars: Michael‐Type Addition to 2‐Nitro‐D‐galactal
Author(s) -
Das Jagattaran,
Schmidt Richard R.
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199808)1998:8<1609::aid-ejoc1609>3.0.co;2-1
Subject(s) - chemistry , nitro , disaccharide , catalysis , raney nickel , selectivity , glycoside , derivative (finance) , acetylation , organic chemistry , medicinal chemistry , acetic acid , base (topology) , glycal , stereoselectivity , biochemistry , mathematical analysis , alkyl , mathematics , financial economics , economics , gene
Formation of 3,4,6‐tri‐ O ‐benzyl‐2‐nitro‐ D ‐galactal ( 3 ) was readily accomplished starting from tri‐ O ‐benzyl‐ D ‐galactal ( 1 ) by acetyl nitrate addition to 2 and base‐promoted acetic acid elimination. Addition of alcohols to 3 under conditions of base catalysis afforded 2‐deoxy‐2‐nitrogalactopyranosides 4a–e in high yields; high α‐selectivity was obtained with strong bases, whereas weaker bases furnished mainly the corresponding β‐galactopyranosides. Chemoselective nitro group reduction in these glycosides was successfully carried out in the case of disaccharide 4cα using Raney nickel as catalyst, thereby affording after N ‐acetylation the corresponding 2‐acetylamino‐2‐deoxy derivative 5cα .