Abstract
Kinsenoside (1) and goodyeroside A (2), two naturally occurring stereoisomers with diverse biological activities, have been synthesized efficiently by a chemo-enzymatic approach with a total yield of 12.7%. The aglycones, (R)- and (S)-3-hydroxy-γ-butyrolactone, were prepared from d- and l-malic acid by a four-step chemical approach with a yield of 75%, respectively. These butyrolactones were then successfully glycosidated using β-d-glucosidase as a catalyst in a homogeneous organic-water system. Under the optimized enzymatic conditions, the yields of kinsenoside and goodyeroside A in the enzymatic steps both reached 16.8%.
Highlights
Kinsenoside (1) and goodyeroside A (2), two naturally occurring stereoisomers with diverse biological activities, have been synthesized efficiently by a chemo-enzymatic approach with a total yield of 12.7%
In order to overcome these challenges, we have adopted a chemical process to synthesize 3-hydroxy-γ-butyrolactones from malic acid in three steps according to a reference procedure with some modifications
The obtained (R)- and (S)-3-hydroxy-γ-butyrolactones were reacted with β-D-glucose as glycosylation agent and β-D-glycosidase as catalyst to prepare kinsenoside
Summary
3-(R)-3-β-D-Glucopyranosyloxybutanolide (kinsenoside, 1, Figure 1) has been isolated from three. Pharmacological investigations on rats demonstrated that 1 possessed several other significant effects, including antihyperliposis [7], anti-inflammatory [8], antihyperglycemic [3], vascular protection [9], ovariectomy-induced bone loss preventive, and osteoclastogenesis suppressing properties [10] In light of their effective physiological activities in vitro and in vivo, preparations of compounds 1 and 2 to meet the need of these compounds for further pharmacological studies have been described in the literature. In one of these approaches, the key chiral intermediates (R)- and (S)-3hydroxy-γ-butyrolactone were initially synthesized, and reacted with 2,3,4,6-tetra-O-benzyl-β-Dglucopyranosyl trichloroacetimidate to afford 1 and 2 in a total yield of 0.8% after seven steps [11]. Reaction conditions for the enzymatic step were optimized by single factor and orthogonal experimental design
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