Angular-type pyranocoumarins from Peucedani Radix (Chinese name: Qian-hu) have exhibited potential for use on treatment of cancer and pulmonary hypertension. Due to the existence of C-3′ and C-4′ chiral centers, compounds belonging to this chemical type commonly exist in enantiomers and/or diastereoisomers, which may elicit distinct activities during their interactions with the human body. In the present study, a new method, which combines enzymatic hydrolysis with chiral LC-MS/MS analysis, has been developed to determine the absolute configurations of these angular-type pyranocoumarins. Pyranocoumarins isolated from Qian-hu, their enantiomers, or metabolites were individually incubated with rat liver microsomes. As the common end product from enzymatic hydrolysis of all tested pyranocoumarins, cis-khellactone was collected and its absolute configuration was determined by comparison with (+)-cis-khellactone and (−)-cis-khellactone using chiral LC-MS/MS. The absolute configurations of all tested parent pyranocoumarins were determined by combination of LC-MS/MS, NMR and polarimetric analysis. The results revealed that the metabolite cis-khellactone retained the same absolute configurations of the stereogenic carbons as the respective parent compound. This method was proven to be rapid and sensitive and also has advantages in discriminating single enantiomers and mixtures of optical isomers with different ratios.

In this work, the ion exchange resin catalyst named D072 were used in the hydrolysis of a methyl acrylate to acrylic acid and methanol firstlyand chemical equilibrium would be achieved during the process of the reversible reaction system. The influences of parameters such as dosage of catalyst, initial reactants molar ratio and reaction temperature were investigated. Meanwhile, the reusability of cation-exchange resin was studied, and no phenomenon of deactivation was found with using of reused catalyst. Moreover, the experimental data were analyzed by the pseudo-homogeneous (PH) model and the hydrolysis dynamics equation of methyl acrylate was obtained and found that the activation energy of the reaction was 118.37 KJ/mol in the presence of D072. Based on the result, high energy would be needed to the hydrolysis of methyl acrylate in using D072 resin as catalyst.