A series of hydrazone and N-acylhydrazone derivatives of dehydroabietic acid were synthesized and evaluated for BK channel-opening activities in an assay system of CHO-K1 cells expressing hBKa channels.The assay results indicated that the activities of the investigated compounds were influenced by the physicochemical properties of the substituent at hydrazone moiety.
Three novel dehydroabietate oxime derivatives were synthesized from dehydroabietic acid and their crystal structures were determined by X-ray crystallographic techniques. All of these 12-oxime dehydroabietic acid derivatives crystallize in orthorhombic system, space group P212121. In the structures, rings A and B exhibit chair and half-chair configurations, respectively and form trans ring junction with two methyl groups（C（19） and C（20）） in the axis positions. The oxime groups have E conformations. Comparison of conformations reveals subtle differences principally in ring B due to the modification in C（12）. The E-acetaldehyde oxime derivative 2c showed distinct BKα gate-opening activity with an ionic current increase of 164% at 30 μM versus the control current.
Two novel taxoids were synthesized from 1-deoxybaccatin Ⅵ and their crystal structures were determined by X-ray crystallographic techniques. The influences of oxetane ring on molecular conformations and bioactivity were investigated. The result shows that the oxetane ring plays an important role in the conformation and bioactivity of the diterpenoid core. In the structure of compound 3, the six-membered A ring exhibits the 1,4-di-planar conformation, the eightmembered B ring adopts a boat-chair conformation, and the six-membered C ring exhibits a slightly distorted half-chair conformation. However, in D-seco-taxoid 4, the six-membered C ring exhibits a boat conformation with the release of ring strain for the D-ring opening.
Two novel 2-(4-(9,9-disubstitued-9 H-fluoren-2-yl)phenyl)-9,9-diethyl-l-phenyl-1,9-dihydrofluoreno-[2,3-d]imidazole derivatives 2 a and 2 b were synthesized and characterized.Their photophysical and electrochemical properties,thermal stability property,and electroluminescence(EL)performance of 2 b were investigated.The fabricated device based on 2 b doping into 4,4’-N,N’-dicarbazole-biphenyl(5%)as an emitter present a maximum brightness of 1272 cd/m^2 at 4 V with the CIE coordinate of(0.1590,0.0465).
Xueying WangZhangcheng LiaoTianqi WangHaixia LinZixing WangYongmei Cui
The syntheses and preliminary biological evaluation of a potentially bioreductive A-mustard and paclitaxel conjugate prodrug 3 targeting hypoxic tumor tissue are described. Aromatic nitro group was used as the bio-reductive trigger. Generation of paclitaxel occurred after reduction via a subsequent mechanism of ＂cyclization-cyclization-extrusion＂. The prodrug was stable in PBS （pH = 7.4） and released paclitaxel after chemical reduction of the nitro fimctionality. In aerobic cytotoxicity assays, it exhibited diminished cytotoxicity and is a candidate for further biological evaluation.
