Synthesis of amino-substituted hexo- and heptopyranoses from D-galactose.
After condensation of D-galactose with two equivalents of acetone, the last free hydroxy group was transformed into an acylated amino group by Swern oxidation, oxime formation, LiAlH4 reduction and acylation. The intermediate aldehyde was homologated with the Wittig reagent, (methoxymethyl)triphenylphosphonium chloride, to afford, after careful hydrolysis, a homologous heptodialdo-1,5-pyranose. Condensation of the aldehyde with hydroxylamine and subsequent LiAlH4 reduction provided a bis-O,O-isopropylidene-protected 7-amino-6,7-dideoxygalactoheptopyranose, which was acylated with various carboxylic acid derivatives. The isopropylidene protective groups were cleaved by careful hydrolysis or alcoholysis to yield 6-acylamino-6-deoxy-galactopyranoses and 7-acylamino-6,7-dideoxy-galactohepto-pyranoses.
Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster, Hittorfstrasse 58-62, D-48149 Münster, Germany.
Benedikt
B
Streicher
Bernhard
B
Wünsch
D000606:Amino Sugars / Q000138:chemical synthesis* / Q000737:chemistry*; D002855:Chromatography, Thin Layer; D005690:Galactose / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared
D000606:Amino Sugars; D005690:Galactose