ISSN:
0075-4617
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Partial Esterification of α-Methyl-D-glucopyranoside with N-(Tri-O-methylgalloyl)imidazole1)Reaction of corresponding quantities of N-(tri-O-methylgalloyl)imidazole with α-methyl-D-glucopyranoside affords α-methyl-6- (1), α-methyl-2,6-bis- (2), and α-methyl-2,3,6-tris(tri-O-methylgalloyl)-D-glucopyranoside (3). With the same N-acylimidazole both α-methyl-2-(tri-O-methylgalloyl)-6-(O-trityl)- (5) and α-methyl-2,3-bis(tri-O-methylgalloyl)-6-(O-trityl)-D-glucopyranoside (6) can be obtained from α-methyl-6-(O-trityl)-D-glucopyranoside (4). Cleavage of the trityl groups from 5 and 6 yields α-methyl-2-(tri-O-methylgalloyl)- (7) and α-methyl-2,3-bis(tri-O-methylgalloyl)-D-glucopyranoxide (8). This selective acylation is caused by intramolecular hydrogen bonds. - The compounds 1,2,3,7, and 8 were investigated by NMR spectroscopy. For the purpose of further structural determinations they were first methylated to give compounds 9, 10, 11, 12, and 13; subsequent cleavage of the acyl groups afforded the compounds 14-18. The latter compounds 14-18 and their silylation products 19-23 were investigated by mass spectrometry.
Notes:
Bei Einwirkung entsprechender Mengen N-(Tri-O-methylgalloyl)imidazol auf α-Methyl-D-glucopyranosid entstanden α-Methyl-6- (1), α-Methyl-2,6-bis- (2) und α-Methyl-2,3,6-tris-(tri-O-methylgalloyl)-D-glucopyranosid (3). Aus α-Methyl-6-(O-trityl)-D-glucopyranosid (4) wurden mit diesem Acylierungsmittel α-Methyl-2-(tri-O-methylgalloyl)-6-(O-trityl)- (5) und α-Methyl-2,3-bis(tri-O-methylgalloyl)-6-(O-trityl)-D-glucopyranosid (6) erhalten. Nach Abspaltung der Tritylgruppen ergaben 5 und 6 α-Methyl-2-(tri-O-methylgalloyl)- (7) und α-Methyl-2,3-bis(tri-O-methylgalloyl)-D-glucopyranosid (8). Diese selektive Acylierung ist auf das Auftreten von intramolekularen Wasserstoffbrücken zurückzuführen. - Die Verbindungen 1, 2, 3, 7 und 8 wurden NMR-spektroskopisch untersucht; ihre weitere Strukturbestimmung erfolgte durch Methylierung zu 9, 10, 11, 12 und 13 und anschließende Abspaltung der Acylgruppen. Von den dabei entstandenen Verbindungen 14-18 sowie deren Silylierungsprodukten 19-23 wurden die Massenspektren aufgenommen.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jlac.197419740103
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