New Triterpenoid and Anti-Inflammatory Constituents of Eriobotrya deflexa f. deflexa

Chemistry of Natural Compounds - A new triterpenoid, methyl 2α-(4-hydroxybenzoyl)oxy-3β-hydroxy-urs-12-en-28-oate (1), has been isolated from the leaves of Eriobotrya deflexa f. deflexa,...     

Facile Selective Diels-Alder Reactions of Chiral 5, 5-Dimethyl-4,6-Mathano-2-Methoxycarbonyl-2-Cyclohexenone. Application to the Total Synthesis of Qinghaosu

Starting from (--)-β-pinene,an efficient synthesis of qinghaosu (8) in natural form hasbeen accomplished. The synthesis involves keto ester 7 as a key intermediate which is conveniently pre-pared using the Diels-Alder chemistry developed in our laboratory.     

13C NMR Substituent Parameters of Dithioacetal Groups in Benzene Derivatives. The σp+ Values of Cyclic Dithioacetals

The ¹³C NMR spectra of forty-six cyclic dithioacetals and their derivatives have been studied. A set of shift parameters was established for each of these heterocycles as substituent. Based on the Hammett type correlation for substituted benzenes, the σ_P ⁺values of cyclic dithioacetal groups have been determined.