Synthesis of the Hydroxyamino Sugar of Calicheamicins

✍ Scribed by Rainer, Hildegard ;Scharf, Hans-Dieter

• Book ID: 102365395
• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 471 KB
• Volume: 1993
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199319930121

✦ Synopsis

Abstract

Methyl 6‐deoxy‐2,3‐O‐isopropylidene‐4‐O‐mesyl‐α‐D‐galactopyranoside (6) was prepared from D‐galactose in six steps. 6 was subjected to a nucleophilic displacement reaction with sodium azide as the nucleophile to yield methyl 4‐azido‐4,6‐dideoxy‐2,3‐O‐isopropylidene‐α‐D‐glucopyranoside (7) in 75% yield. Reduction of the azido group with NaBH~4~ afforded the amino sugar 8 (81%) which was adsorbed on silica gel and subsequently oxidized with ozone to methyl 4,6‐dideoxy‐2,3‐O‐isopropylidene‐4‐nitro‐α‐D‐glucopyranoside (10, 80%). This crystalline and stable compound 10 was reduced with Zn/NH~4~Cl to yield the desired methyl 4,6‐dideoxy‐4‐hydroxy‐amino‐2,3‐O‐isopropylidene‐α‐D‐glucopyranoside (11, 85%), which is unstable to air and therefore has to be transferred to its N,O‐diacetate derivate 12. No chromatographic purification was necessary.