Synthesis of Homogalacturonan Fragments |
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Authors: | Sven Kramer Birte Nolting Andrej-Jakob Ott Christian Vogel |
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Affiliation: | 1. Department of Biochemistry , University of Missouri , Columbia, MO, 65211, U.S.A;2. Institute of Chemistry, Slovak Academy of Sciences , 842 38, Bratislava, Czechoslovakia;3. Department of Chemistry , University of Missouri , Columbia, MO, 65211, U.S.A;4. Department of Biochemistry , University of Missouri , Columbia, MO, 65211, U.S.A |
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Abstract: | ABSTRACT Glycosylation of the D-galacturonic acid ester derivatives 15 and 17, which are prepared directly from D-galacturonic acid, with the thioglycosides 28 and 32, derived from the same sugar, provides α(1→4)-linked dimers. The formation of the glycosidic linkage between the galacturonic acid moieties is best achieved by iodonium di-sym-collidine perchlorate promotion. Thus, the 4'-O-p-methoxybenzyl dimer 38 can be obtained in 64% yield. Partial deprotection of the 4'-O-position provided the glycosyl acceptor 36, which was coupled with the donor 32 to yield the α(1”→4')-linked trimer 39 (48%). Approximately 8% of the β(1”→4')-coupled isomer was observed in the 13C NMR spectrum of the reaction mixture. |
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