The absolute configurations of angelols A-H (1-8) isolated from Angelica pubescens MAXIM. (Umbelliferae) were determined to be as shown in Chart 1 by means of chemical, spectral and X-ray analysis. Furthermore, the stereostructure of angelol B (2) was determined to be as shown in Fig. 1 on the basis of X-ray analysis.
The Effect of Phenyl Substituents on the Release Rates of Esterase-Sensitive Coumarin-Based Prodrugs.
作者:Yuan LIAO、Siska HENDRATA、Sung Yong BAE、Binghe WANG
DOI:10.1248/cpb.48.1138
日期:——
peptidomimetics. The drug release rates from this prodrug system were found to be dependent on the structural features of the drug moiety. In certain cases, the release can be undesirably slow for drugs that are secondary amines with relatively high pKa's. Aimed at finding ways to manipulate the release rates to suit the need of different drugs, we have examined the effect of the phenyl ring substitutions
A new and efficient method for the reduction of α,β-unsaturated carboxylic esters to allylic alcohols utilizing LiAlH4/BnCl is described. Various α,β-unsaturatedesters, including the coumarins bearing α,β-unsaturated lactone skeleton, can be converted smoothly into their corresponding allylic alcohols in high yields under mild conditions with short reaction times.