ISSN:
0170-2041
Keywords:
Calonyctin A
;
Saccharides
;
Resin glycosides
;
Glycosides
;
Trichloroacetimidates
;
Carbohydrates
;
D-Quinovose
;
L-Rhamnose
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
3-O-Benzyl-protected quinovose 6 was transformed into 1,2-O-unprotected derivative 9 which on treatment with TBS-Cl in the presence of a base gave selectively 2-O-unprotected glycosyl acceptor 10. Similarly, 3-O-allyl-protected quinovose 11 was transformed into 1,2-O-unprotected derivative 14. 1,2-O-Acetylation of 14, selective removal of the 1-O-acetyl group with hydrazinium acetate, and subsequent treatment with trichloroacetonitrile in the presence of DBU furnished the versatile 2-O-acetyl-3-O-allyl-protected quinovosyl donor 17. Reaction of donor 17 with acceptor 10 in the presence of TMSOTf as the catalyst gave disaccharide 19. Treatment of 19 with NaOMe/MeOH provided 2b-O-unprotected derivative 20 which gave with rhamnosyl donor 18 in the presence of TMSOTf as the catalyst trisaccharide 21. 3b-O-Deallylation of 21 and subsequent reaction with donor 17, again in the presence of TMSOTf as the catalyst, gave target tetrasaccharide 2. Removal of all O-protective groups furnished D-Quiß(1→3)[L-Rhaα(1→2)]D-Quiß(1→2)D-Qui (3), the tetrasaccharide moiety of calonyctin A.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.199419940702
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