lignans and veratraldehyde

A synthesis of natural tetrahydrofuran lignan (+)-sylvone is achieved starting from methyl allenoate in 5 steps. The synthesis begins from an enantioselective aldol reaction of methyl allenoate with 3,4-dimethoxybenzaldehyde to afford α-addition aldol adduct. Key steps for the synthesis of sylvone include an oxacyclization of the α-hydroxy allenyl adduct followed by a Michael addition of a 1,3-dithiane derivative to establish a sylvone skeleton with suitable stereoselections.

Topics: Benzaldehydes; Catalysis; Furans; Heterocyclic Compounds; Lignans; Molecular Structure; Naphthalenes; Stereoisomerism

A series of naturally occurring 8.0.4'-neolignans (1a-d, 1g, 2g, 2h) and their analogues (le-f, lh, 1i, 2a-f, 2i) have been synthesized in racemic form starting from commercially available phenols, such as eugenol, isoeugenol and 4-allyl-2,6-dimethoxyphenol and from aromatic aldehydes, such as piperonal, veratraldehyde and 3,4,5-trimethoxybenzaldehyde. The inhibitory activity of these compounds on superoxide anion (O2.-) release by human polymorphonuclear leukocytes (PMNLs) was tested and the structure-activity relationship was also studied.

Topics: Aldehydes; Antioxidants; Benzaldehydes; Benzodioxoles; Cells, Cultured; Eugenol; Humans; Lignans; Neutrophils; Phenols; Quantitative Structure-Activity Relationship; Superoxides

A new cyclobutane lignan, named cinbalansan (6), was isolated from the leaves of Cinnamomum balansae, along with five known compounds, 1,2-dimethoxy-4-(1-E-propenyl)benzene (1), 1,2-dimethoxy-4-(1-Z-propenyl)benzene (2), 1,2-dimethoxy-4-(2-propenyl)benzene (3), 3,4-dimethoxybenzaldehyde (4), and E-(3,4-dimethoxyphenyl)-2-propenal (5). The structure of cinbalansan was shown to be 1beta,2beta,3alpha,4alpha-1,2-dimethyl-3,4-bis(3,4-dimethoxyphenyl)cyclobutane by a combination of 1H-, 13C-NMR, and NOE- experiments and by direct analysis of the 1H-NMR spectrum by the method of X-application.

Topics: Acrolein; Benzaldehydes; Benzene Derivatives; Chromatography, High Pressure Liquid; Cinnamomum; Cyclobutanes; Lignans; Magnetic Resonance Imaging; Molecular Structure; Plant Leaves; Plants, Medicinal; Vietnam