Pinguisane-Type Sesquiterpenes from the South American Liverwort Porella recurva (Taylor) Kuhnemann
The chemical composition of a dichloromethane extract of the South American liverwort Porella recurva has been examined. Two new pinguisane-type norsesquiterpenoid natural products were isolated: 6,11-epoxy-15-nor-3,4-dioxo-5,10-pinguisadien-12-acetate and 6,11- epoxy-15-nor-4-oxo-5,10-pinguisadien-12-acetate. In addition two known pinguisane-type sesquiterpenes were also isolated: norpinguisone and norpinguisone methyl ester. All structures were elucidated by means of NMR spectroscopic techniques and mass spectrometry.
Sesqui- and diterpenoids from the panamanian liverwort Bryopteris filicina
Abstract Four new pinguisane-type sesquiterpenoids, bryopterins A–D, were isolated from the Panamanian liverwort Bryopteris filicina along with some previously known sesqui- and diterpenoids and the marchantin-type bisbibenzyl, isomarchantin C and their structures determined by extensive NMR techniques and chemical degradation. The stereochemistry of fusicogigantepoxide was determined by X-ray crystallographic analysis. Bryopteris filicina is chemically similar to Ptychantus species.
Copper Phthalocyanine Improving Nonaqueous Catalysis of Pseudomonas cepacia Lipase for Ester Synthesis
The nonaqueous catalysis of lipases is significant for synthesis of high pure esters, but they usually behave low catalytic activity due to denaturation and aggregation of enzyme protein in organic phases. To improve the nonaqueous catalysis, the inexpensive copper phthalocyanine was taken as a new carrier on which Pseudomonas cepacia lipase was immobilized by physical absorption, and used for synthesis of hexyl acetate, an important flavor, via transesterification of hexanol and vinyl acetate. Results showed that the desired loading was 10 mg lipase immobilized on 10 mg copper phthalocyanine powder. When the immobilized lipase was employed in the reaction system consisted of 1.5 mL hexanol and 1.5 mL vinyl acetate at 37℃ and 160 rpm, the conversion was five fold of that catalyzed by native lipase after 1 h, and reached 99.0% after 8 h. Undergoing six times of 8-h reuses, the immobilized lipase had an activity attenuation rate 1.22% h− 1, lower than 1.77% h− 1 of native lipase, which meant that the immobilized lipase was more stable. Even at the room temperature and the static state without shaking or stirring, the immobilized lipase could bring conversion 42.8% after 10 h and the native lipase gave 20.1%. Obviously, the immobilized lipase is an available biocatalyst in organic phase and has great potential in food industry.