Regioselective Enzyme-Mediated Acylation of Polyhydroxy Natural Compounds. A Remarkable, Highly Efficient Preparation of 6'-Acetyl and 6'-O-Carboxyacetyl Ginsenoside Rg1
Lipase B from Candida anturctica has been shown to be an efficient catalyst for the regioselective acylation of the dammarane type glucoside ginsenoside Rg1 (1) on reaction with vinyl acetate in t-AmOH, affording the corresponding 6’-O-acetyl derivative lb in high yield. The structure of lb was dete...
| Published in: | The Journal of Organic Chemistry |
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| Main Authors: | , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
American Chemical Society
1995
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| Subjects: | |
| Online Access: | http://hdl.handle.net/2434/178342 https://doi.org/10.1021/jo00117a012 |
| Summary: | Lipase B from Candida anturctica has been shown to be an efficient catalyst for the regioselective acylation of the dammarane type glucoside ginsenoside Rg1 (1) on reaction with vinyl acetate in t-AmOH, affording the corresponding 6’-O-acetyl derivative lb in high yield. The structure of lb was determined through a careful inspection of its lH NMR at 600 MHz, which allowed for the complete assignment of the signals of the sugar’s protons. The introduction of a carboxyacetyl residue was then investigated using different protocols. The best results were obtained with a two-step sequence involving the preliminary enzymatic acylation of 1 with bis(2,2,2-trichloroethyl) malonate to give the mixed malonyl derivative lf, followed by selective chemical hydrolysis with ZdAcOH to the 6’-O-carboxyacetyl ginsenoside Rg1 (le). |
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