Lignans sugars

Two different classes of optically active a-hydroxylated lignans have been prepared from sugars by Yamauchi and co-workers lactone lignans [47, 48] and tetrahydrofuran lignans [49, 50]. In both cases, only model compounds were synthesized, such as lactone lignan 55 (Scheme 13), as a result of the synthetic strategy. The key intermediate for the synthesis of lactone lignan... 

The chiral lactone (178) has been used for the synthesis of a variety of natural products, such as sugars, lignans, terpenes, alkaloids, and P-lactams as a chiral building block 182c,184). The use of (178) as a powerful inductor of asymmetry was mainly established by Takano et al. 181, 84> one can expect more highly interesting reports from this group. 

Sugar, alkaloids, lectins, flavanoids, phenyl allyl alcohols, lignans, triterpenes, polypeptides... 

This review of literature covering phytochemical investigations on ten Taxus species have resulted in the isolation of nearly three hundred and fifty compounds belonging to the classes of taxanes, lignans, flavonoids, steroids, sugar derivatives, aromatic acids, etc. 

In an approach to the olivil type of lignan (Scheme 19), the erythro-aldol product 96 was produced as a 1 1 mixture with the threo-isomer by reaction between piperonal and a lactone derived from D-xylose. Manipulation of 96 gave the diol 97 (sugar carbons numbered), which underwent acid-catalysed cycliz-... 

However, there are exceptions, such as the isoflavone irilone, which seems to be resistant to bacterial conversion [85]. Gut bacteria catalyze an array of dominant core reactions that play key roles in the metabolism of a large panel of phenolic compounds, including isoflavones and lignans (I) hydrolysis of esterified and conjugated bounds, (II) deglycosylation (removal of sugar moieties),... 

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