Christiane Schneider

Application of the asymmetric chelate-enolate claise rearrangement to the synthesis of 5-epi-isofagomine

Abstract Chelate-enolate Claisen rearrangement of a N -protected chiral amino acid ester gave rise to a γ,δ-unsaturated amino acid, which could be converted to the potential glycosidase inhibitor 5- epi -isofagomine ( 9 ) in a straightforward and a highly stereoselective fashion.

Synthesis of 5‐epi‐Isofagomine via Asymmetric Chelate–Enolate Claisen Rearrangement

Polyhydroxylated piperidines are an interesting class of glycosidase inhibitors. Chelate enolate Claisen rearrangement of N-protected chiral amino acid esters gives rise to γ,δ-unsaturated amino acids, which can be converted to this type of alkaloids. The potential glycosidase inhibitor 5-epi-isofagomine (5) was synthesized by this approach in a highly stereoselective fashion.

Cyclobakuchiols A and B from Psoralea Glandulosa

Bioactivity guided fractionation of the dichloromethane extract from Psoralea glandulosa yielded the isolation of a diasteromeric mixture of cyclobakuchiols A and B as possible anti-inflammatory active compounds.

A 4-methyl-7-hydroxyphthalide glycoside and other constituents from Quillaja saponaria Molina

A so far unknown 4-methyl-7-hydroxyphthalideglycoside has been isolated from the methanol extract of the bark of Quillaja saponaria molina. Its structure has been established from NMR experiments as 7-O(-)[beta-glucopyranosyl-(1-->6)-beta-arabinopyranosyl]-7-hydrox y-4-methy l -1[3H]-isobenzofuranone. Two known compounds, 3,4,5-trimethoxyphenyl-beta-D-glucopyranoside and lyoniresinol-3 alpha-O-beta-D-glycopyranoside were also identified.