Free-radical mediated stannylcarbonylation of azaenynes provides a general [n + 1]-type annulation approach leading to alpha-stannylmethylene lactams. The cyclization is unusual in its breadth, covering 4-exo, 5-exo, 6-exo, 7-exo, and 8-exo modes.

We have investigated the aroma of yuzu (Citrus junos Sieb. ex Tanaka). Application of the aroma extract dilution analysis technique allowed us to determine a sequence of the odour‐active compounds in yuzu volatile oil. In this study, we confirmed the presence of an unknown odorant that possesses a sweaty odour and a relatively high flavour dilution factor. In order to identify the unknown compound, the concentrated volatile acid fraction of yuzu volatile oil was obtained, using an enrichment procedure consisting of the combination of the sub‐extraction of an acidic component with a basic aqueous solution and subsequent affinity chromatography with an Oasis MAX cartridge. Gas chromatography–olfactometry and multi‐dimensional gas chromatography–mass spectrometry analyses revealed that the unknown compound was (E)‐4‐methyl‐3‐hexenoic acid [(E)‐4M3H]. (E)‐4M3H was identified for the first time as an odour‐active unsaturated aliphatic acid in yuzu. Additionally, both (Z)‐ and (E)‐4M3H were stereoselectively synthesised over two steps comprised of the iron‐catalysed carbometalations of homopropargylic alcohols with Grignard reagents, followed by oxidation. On the basis of sensory evaluation, the orthonasal odour detection threshold of the (E)‐isomer was 10‐fold to 100‐fold lower than that of the (Z)‐isomer. Copyright © 2012 John Wiley & Sons, Ltd.

In this study, the biological activity of 20 essential oils (EOs) from herbal plants and citrus fruits were investigated in terms of mammalian DNA polymerase (pol) inhibitory activity, cancer cell (human colon carcinoma, HCT116) growth inhibitory activity, antiallergic activity, as anti-β-hexosaminidase release activity in rat basophilic leukemia RBL-2H3 cells treated with calcium ionophore A23187, and antioxidant activity by a lipophilic-oxygen radical absorbance capacity method. These EOs showed patterns of inhibition of pol α, a DNA replicative pol, similar to their cancer cell growth inhibitory activity, and their inhibitory activity on pol λ, a DNA repair/recombination pol, by the EOs showed correlation with anti-β-hexosaminidase release activity. Among these EOs, chamomile (Matricaria chamomilla L.) was the strongest inhibitor of pols α and λ and showed significant effects on both cancer cell growth and mast cell degranulation. On the basis of these results, chamomile EO can be recommended as a potentially useful, bioactive candidate for therapeutic applications.

We investigated the effects of geranium essential oil (GEO) on anaphylaxis. GEO can exert antioxidant and anti-inflammatory effects, but its roles in allergic reactions are incompletely understood. Here, we used mouse cells to show that GEO inhibited the degranulation of cultured mast cells (CMCs). Citronellol is the major component of GEO and inhibited CMC degranulation. The l-enantiomer of citronellol more effectively suppressed CMC degranulation than did d-citronellol. We also examined whether citronellol could inhibit the immunoglobulin (Ig) E-induced production of tumor necrosis factor (TNF)-α. Treatment with various concentrations of citronellol before CMC activation with IgE significantly inhibited the induction of TNF-α in a dose-dependent manner. Mechanistically, citronellol suppressed the phosphorylation of mitogen-activated protein kinase (ERK), which is critical for ERK activation and the production of inflammatory cytokines in mast cells. These findings suggest that citronellol may represent a candidate compound for the effective treatment of allergic diseases.