Syntheses of Guanidinoglycosides with the Inventive use of Mitsunobu Conditions­ and 1,8-Diazabicyclo[5.4.0]undec-7-ene

Abstract

A series of novel guanidinoglycosides was successfully synthesized. This was accomplished with the use of Mitsunobu conditions as a strategy to convert the glycopyranose anomeric hydroxy group to give the corresponding substituted masked guanidines in high yields. Subsequent deprotection and coupling with Fmoc protected β-amino acid, afforded a series of N,N′-substituted-methylisothioureas. Cleavage of Fmoc followed by concomitant cyclization was achieved with a catalytic amount of DBU to give the guanidinoglycosides.

Key words

guanidine - glycosides - Mitsunobu reaction - coupling - cyclization

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1

First and second authors contributed equally to this work.

12

To further prove the existence of rotomers, Boc-protection of 2 was carried out using Boc₂O and DMAP in CH₂Cl₂. Both 2a and 2b yielded only their respective α rotomers.