Total Synthesis of the Antiallergic Naphtho-α-pyrone Tetraglucoside, Cassiaside C2, Isolated from Cassia Seeds
- 8 July 2003
- journal article
- research article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 68 (16) , 6309-6313
- https://doi.org/10.1021/jo034223u
Abstract
Toralactone 9-O-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranosyl-(1-->3)-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranoside (1, cassiaside C(2)), isolated from Cassia obtusifolia L. and showing strong antiallergic activity, was concisely synthesized employing glycosyl trifluoroacetimidates as glycosylation agents. The unique naphtho-alpha-pyrone structure of toralactone (5) was constructed by condensation of orsellinate 8 with pyrone 9 in the presence of LDA as developed by Staunton and co-workers. The naphthol of toralactone showed minimal reactivity as an acceptor and was screened with various glycosyl donors. It is finally concluded that sacrifice of an excess amount of the trifluoroacetimidate or trichloroacetimidate donors (6f/6g, 6.0 equiv) in the presence of a catalytic amount of TMSOTf (0.05 and 0.3 equiv, respectively) afforded excellent yields of the coupling product, which was otherwise only a minor product under a variety of conditions examined.Keywords
This publication has 34 references indexed in Scilit:
- Highly Efficient β-Glucosylation of the Acidic Hydroxyl Groups, Phenol and Carboxylic Acid, with an Peracetylated Glucosyl Fluoride Using a Combination of BF3 · Et2O and DTBMP as a PromoterSynlett, 1999
- Synthesis of Vancomycin from the AglyconJournal of the American Chemical Society, 1999
- Phenolic Constituents of Cassia Seeds and Antibacterial Effect of Some Naphthalenes and Anthraquinones on Methicillin-Resistant Staphylococcus aureus.CHEMICAL & PHARMACEUTICAL BULLETIN, 1999
- Antiallergic Agent from Natural Sources. Structures and Inhibitory Effect of Histamine Release of Naphthopyrone Glycosides from Seeds of Cassia obtusifolia L.CHEMICAL & PHARMACEUTICAL BULLETIN, 1998
- Synthesis of a New Phenol Glycoside, Neohancoside C from Cynanchum hancockianum.CHEMICAL & PHARMACEUTICAL BULLETIN, 1997
- Asymmetric Diels–Alder reactions. Part 5. Influence of sugar substituents upon the diastereofacial reactivity of (E-)3-(t-butyldimethylsiloxy)-1-(D-glucopyranosyloxy)buta-1,3-dienesJournal of the Chemical Society, Perkin Transactions 1, 1990
- Stereocontrolled Synthesis of 6′-Deoxy-6′-Fluoro Derivatives of Methyl α-Sophoroside, α-Laminaribioside, α-Kojibioside and α-NigerosideJournal of Carbohydrate Chemistry, 1988
- Studies on the constituents of the seeds of Cassia obtusifolia L. The structures of two naphthopyrone glycosides.CHEMICAL & PHARMACEUTICAL BULLETIN, 1988
- Biomimetic syntheses of polyketide aromatics from reaction of an orsellinate anion with pyrones and a pyrylium saltJournal of the Chemical Society, Perkin Transactions 1, 1984
- Chemical Studies on the Oriental Plant Drugs. XXI. The Constituents of Cassia tora L. (2). A Glycoside of RubrofusarinCHEMICAL & PHARMACEUTICAL BULLETIN, 1969