Squaramide-catalysed asymmetric Friedel-Crafts alkylation of naphthol and unsaturated pyrazolones.

The first method for highly efficient asymmetric Michael-type Friedel-Crafts alkylation of naphthol and unsaturated pyrazolones has been accomplished under mild reaction conditions. In the presence of the chiral squaramide catalyst, a wide range of substrates are tolerated in excellent yields (up to 99%) with reasonable enantioselectivities (up to 96% ee).

Synthesis and biological activities of new halophenols.

A series of new halophenols were synthesized, and their structures were established on the basis of 1H, 13C NMR and mass spectral data. All of the prepared compounds were screened for their in vitro protein tyrosine kinase (PTK) and vascular smooth muscle cell (VSMC) proliferation inhibitory activity. Twelve halophenols showed significant PTK inhibitory activity, most of them exhibited stronger activities than that of genistein, a positive reference compound. Several halophenols also displayed moderate VSMC proliferation inhibitory activity, compound 8c showed higher activity than that of tetrandrine, a positive reference compound. The preliminary structure-activity relationships of these compounds were investigated and discussed. The results provided a foundation for the action mechanism study and further structure optimization of the halophenols.

[Application of three-phase hollow fiber liquid-phase microextraction for analysis of hydroxybenzoic acids].

Under the optimal experimental conditions of three-phase hollow fiber liquid-phase microextraction (3p-HFLPME), the behaviors of hydroxybenzoic acids (HBAs) were investigated. The correlation between the enrichment factor (EF) of HBAs and their n-heptanol/water conditional distribution coefficients (log P(n-heptanol/5 mmol/L) HCl), pK(a) mmol/L HCI ), and the number of -OH (N); the extraction mechanism that polyvinylidene difluoride hollow fiber contributed to promote the extraction efficiency by forming charge transfer compound with HBAs and the organic solvents showed notable selectivity for HBAs were elucidated. The optimal 3p-HFLPME conditions were: MOF 503 polyvinylidene difluoride hollow fiber as organic solvent supporter, n-heptanol as organic phase, 5 mmol/L HCl in the donor phase and 80 mmol/L NH3 x H2O as the acceptor phase, the HBAs were extracted for 35 min under an agitation of 1 200 r/min. It was found that the relative standard deviations were lower than 3%, the detection limits were 0.09-30.00 microg/L, the average recoveries of HBAs in Calyx Kaki were 93.3%-107.1% and the EF of HBAs at 5 mg/L was up to 107.6 fold.