PHOTOINDUCED ADDITION REACTIONS OF CHLORANIL WITH FURAN DERIVATIVES

Photoinduoed reaction of chloranil (TCBQ) with 2-methylfuran la and 2,5-dimethylfuran 1b in benzene gave addition products 2a and 2b respecvely together with tetrachlorohydroquinone 3. A mechanism of sequential electron and proton transfer from la or 1b to ~3TCBQ followed by coupling of the furfuryl and semiquinone radical pairs was proposed and is evidenced by the photo-CIDNP studies of the TCBQ-1a and TCBQ-1b systems.

LOW-VALENT TITANIUM INDUCED REACTION OF CARBOXYLIC DERIVATIVES WITH NITRO COMPOUNDS

The intermolecular reaction of carboxylic derivatives with nitro compounds induced by titanium tetrachloride and zine powder was studied.

Studies on the Reaction of Vinyl Triazole Derivatives with Hydroxylamine

In this paper the reaction of vinyl triazole derivatives with hydroxylamine hydrochloride under the action of sodium carbonate was studied. The result indicated that cyclization took place and new heterocyclic compounds of 1,2-oxazocyclopentanes were obtained.

A PRELIMINARY STUDY ON THE THEORY OF THE SECOND AND THIRD ORDER DERIVATIVE ADSORPTION CHRONOPOTENTIOMETRY FOR A REVERSIBLE REACTION

The equations of the second and third order derivative curves of time with respect to potential for a reversible process in adsorption chronopotentiometry are derived and experimentally verified.

Oxygen-promoted Pd/C-catalyzed Suzuki–Miyaura reaction of potassium aryltrifluoroborates

A simple and highly efficient protocol has been developed for the Pd/C-catalyzed ligand-free Suzuki- Miyaura reaction of potassium aryltrifluoroborates. In this catalytic system, the results demonstrate that oxygen plays a positive role in the cross-coupling reaction. In addition, this catalytic system could be successfully applied to synthesize biaryl compounds containing a carbazole moiety and the catalyst was recycled seven times without significant loss of catalytic activitv.

THE ELECTRON SPIN RESONANCE STUDY ON PRIMARY PHOTOCHEMICAL REACTION OF HEMATOPORPHYRIN DERIVATIVE

The rate of oxygen consumption and the yield of free radical anion of hematoporphyrin derivative (HPD) in aqueous solutions of HPD and pyrocatechol were measured by the probe 2,2,6,6-tetramethyl4-piperidone-1-oxyl.It has been found that both singlet oxygen and free radical mechanisms exist simultaneously in primary photochemical reactions, and there is a competition between both mechanisms. When the oxygen concentration in solutions comes down to 12-14% of the stanting level, the predominant mechanism can be changed from the singlet oxygen to the free radical.Whether HPD exists in aggregation state is very important to photosensitization mechanisms.In the presence of the aggregation state of HPD, the predominant mechanism is the free radical,and photosensitization effects of HPD are all the better.

A novel regio-and stereo-specific hydrohalogenation reaction of 2-alkynoic acids and their derivatives

The nucleophilic hydrohalogenation of 2-alkynoic acids anti their derivatives by heating with lithium halides iu HOAc afforded the thermodynamically unfavorable 3-halo-2 (Z)- alkenoic acids and their derivatives stereospecifically

Design and synthesis of biotinylated dimethylation of alkannin oxime derivatives

DMAKO-05,a novel dimethylation of alkannin oxime derivative,exhibits remarkable anticancer activity as well as excellent cellular selectivity and thus has been considered as a promising antineoplastic agent for colorectal carcinoma and melanoma.However,its potent cytotoxicity is not closely associated with reactive oxygen species（ROS） and bioreductive alkylation.Its specific antitumor target（s） has still remained elusive.To recognize the molecular target（s） of DMAKO-05 and its analogs,four biotinylated DMAKO derivatives were designed and prepared.The biotin moiety was successfully introduced in the molecule through a modified Mitsunobu reaction,which kept its anticancer activity.Moreover,the cellbased investigation demonstrated that replacement of the linker C4 chain with another alkyl chain（C6 or C8） gave rise to the enhancement of cytotoxicity.Among these biotinyl derivatives,both compound 16 and 8c exhibited more potent anticancer activity than DMAKO-05 against MCF-7 cells and were comparatively effective to alkannin toward HCT-15 cells.As expected,they might be thought as ideal chemical probes.Collectively,our present work could provide an available approach for the identification of the potential antineoplastic target（s） of DMAKO derivatives.

Synthesis and structures of malonate derivative-calix [4] arene conjugates

A series of malonate derivatives-calix[4]arene conjugates were synthesized through Knoevenagel condensation reaction between formyl-tetrapropoxycalix[4]arene and malonate derivatives. The structures of the resulting malonate derivative functionalized calix[4]arenes were characterized by NMR spectroscopy, mass spectrometry and even single crystal X-ray diffraction analysis.

New triazole derivatives containing substituted 1,2,3-triazole side chains:Design,synthesis and antifungal activity

In order to discover new generation of triazole antifungal agents,a series of novel antifungal triazoles were designed and synthesized by structural simplification of our previously identified triazolepiperdine-heterocycle lead compounds.Several target compounds showed good antifungal activity with a broad spectrum.In particular,compound 71 was highly active against Candida albicans and Candida glabrata.Moreover,compound 71 showed potent in vivo antifungal efficacy in the Caenorhabditis elegans-C.albicans infection model.