Synthesis of 6I-amino-6I-deoxy-2I-VII,3I-VII-tetradeca-O-methyl-cyclomaltoheptaose.
The preparation of 6(I)-amino-6(I)-deoxy-2(I-VII),3(I-VII)-tetradeca-O-methyl-cyclomaltoheptaose is reported. Two different routes (A and B), both starting from beta-cyclodextrin (betaCD), have been examined. Route A involved: (i) synthesis of heptakis(6-O-tert-butyldimethylsilyl)-betaCD from betaCD; (ii) permethylation of the secondary hydroxyl groups with methyl iodide and sodium hydride; (iii) desilylation of the primary hydroxyls with ammonium fluoride; (iv) monotosylation at O-6 position of per-(2,3-O-methyl)-betaCD; (5) nucleophilic replacement of the tosyl group with azide anion; (v) reduction of the azido group by catalytic transfer hydrogenation using hydrazine hydrate in the presence of Pd/C in methanol/water. Route B started from the known 6(I)-monoazido-6(I)-monodeoxy-beta-CD (two steps from beta-CD) and entailed: (i) protection of the remaining primary hydroxyls using tert-butyldimethylsilylchloride (TBDMSCl); (ii) exhaustive methylation of the secondary hydroxyls with methyl iodide and sodium hydride; (iii) removal of the TBDMS protecting groups with ammonium fluoride; (iv) reduction of the azido group as above. Route A was found to be less convenient than Route B due to the inherent difficulty of controlling the monotosylation of per-(2,3-O-methyl)-betaCD.
Carofiglio
Tommaso
T
Dipartimento di Scienze Chimiche, and ITM-CNR (sezione di Padova), Università di Padova,Via Marzolo 1, 35131 Padova, Italy. tomasso.carofiglio@uuipd.it
Cordioli
Matteo
M
Fornasier
Roberto
R
Jicsinszky
Laszlo
L
Tonellato
Umberto
U
D015394:Molecular Structure; D047392:beta-Cyclodextrins / Q000138:chemical synthesis* / Q000737:chemistry*
C494279:6(I)-amino-6(I)-deoxy-2(1-VII),3(1-VII)-tetradeca-O-methylcyclomaltoheptaose; D047392:beta-Cyclodextrins