Penicillin G acylase(PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm,specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g.The 96.7%ampicillin yield with 1.60 of the synthesis/hydrolysis(S/H) ratio from 6-aminopenicillanic acid(6-APA) and D-(-)-alpha-phenylglycine methyl ester(D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol,where only 82.1%yield with 1.40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions.The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.
A facile approach for the first total synthesis of two naturally occurring geranylated flavonoids,（±）-puyanin 1 and（±）-4＇-O- methylbonannione 2 has been obtained with total yield 27%and 21%,respectively.The key steps were regioselective cyclization of geranylated trihydroxychalcone and regioselective geranylation of 2,4,6-trihydroxyacetophenone.
Jin Hui Yang Yu Heng Zhang Hong Jun Li Shi Zhi Jiang Yun Feng Li
A facile approach for the first total synthesis of prenylated flavonoids, （±）-abyssinone-VI-4-O-methyl ether 1, （±）-abyssinone- IV-4＇-O-methyl ether 2, （±）-abyssinone-V-4＇-O-methyl ether 3 and （±）-sigmoidin E 4 has been described. The key intermediate 4-hydroxy-3,5-di-（3-methylbut-2-enyl）benzaldehyde 6 was also first synthesized that features regioselective prenylation of 4-hydroxybenzaldehyde and crystallizing with petroleum ether from the reaction mixture by freeze-out effect.
