No abstract

The interaction of tetrahydrofuran (THF), a template, with FER type zeolite was studied by molecular simulation and 13 C high-power decoupling magic angle spinning nuclear magnetic resonance (HPDEC MAS NMR) spectrometry. Molecular dynamics (MD) together with energy minimization (EM) methods were used to simulate the interactions of Si-FER with THF, and with two other templates of pyrrolidine and pyridine for comparison. The interaction energies for these templates located in FER (8 2 6 2 6 4 5 8 ) cage and in the 10 member ring (MR) channel were calculated, respectively. The preferred binding site for each template investigated is the FER cage site. The variation of the calculated potential energy indicates a high-energy barrier for the moving of THF molecule to the 10-MR channel from FER cage. The experiments of 13 C HPDEC MAS NMR demonstrate that the molecules of THF are located in FER cages as the template, and in the 10-MR channels as the adsorbed molecules.

Two new triterpenoid saponins, incarvillosides A (1) and B (2), and two new monoterpenoid glycosides, incarvillosides C (3) and D (4), were isolated from the high-polarity fraction of the whole plant of Incarvillea delavayi. By means of spectroscopic data and chemical degradation, the structures were established as (3beta,21beta)-3,19,21,23-tetrahydroxyurs-12-en-28-oic acid 28-O-beta-d-glucopyranoside (1), (2beta,3beta,19alpha)-2,3,19,23-tetrahydroxyolean-12-en-28-oic acid 28-O-beta-d-glucopyranoside (2), (2S,6R)-2,6-dimethyl-1,8-octanediol 1-O-beta-d-glucopyranoside (3), and (2S,6R)-2,6-dimethyl-1,8-octanediol 8-O-beta-d-glucopyranoside (4).