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In order to better understand the molecular aspects of the cytotoxic action mechanisms, the cytotoxicity of alkannin derivatives, 1-10, on five human tumor cell lines were examined and their standard redox potentials in aprotic medium were tested by means of cyclic voltammetry. It was suggested that the oxidative potential is closely related to the cytotoxicity. The more negative the oxidative potential of the hydroquinones, the higher cytotoxicity of these derivatives. The results of the compounds 5, 7, 9 and 10 with bad leaving groups, have higher cytotoxic action is not agreed with the bioreductive alkylation mechanism of quinones. It indicates that the molecular mechanism involving cytotoxicity of alkannin derivatives may favor the mechanism of production of reactive oxygen.

Three series of functionalized coumarin compounds were designed and prepared as cholinesterase (AChE and BuChE) inhibitors. The biological profile against AChE and BuChE of the prepared compounds was determined. Compound 7b exhibited a mixed-type of AChE inhibitor with IC 50 value for the AChE inhibition of 0.19 ± 0.01 μM and a high selectivity for AChE/BuChE, and compound 6b acted as non-competitive AChE inhibitor with IC 50 value of 0.43 ± 0.02 μM. Structure–activity relationships (SARs) of prepared compounds were discussed.

To study the synthesis and antitumour activities of some aryl-substituted pteridines.A series of aryl-substituted pteridines were synthesized from 4, 6-diamino-5-nitrosopyrimidines by cyclization with 4-aminophenylacetonitriles. The antitumour activities were tested by MTT method.Nine new compounds (I-III) were synthesized and their structures were characterized by EA, IR, 1HNMR and MS spectra. Compounds I-III showed antitumour activities in vitro.Compounds I-III showed remarkable antitumour activities in vitro. No interaction was determined between the title compounds and calf thymus DNA. It indicated that these compounds possibly inhibit dihydrofolate reductase (DHFR) or other enzymes on which folic acid depends.

Inhibition of metal ions and synergetic inhibition of metal ions/genistein on alpha-glucosidase activity has been investigated. We have examined the inhibitory effect of Cu2+, Ni2+, Mg2+, Fe2+, Hg2+, Zn2+, Ca2+, Pb2+, Ag+, V5+, V4+ and Mn2+ ions. The results show that the nature of the inhibition was reversible, slow-binding, non-competitive, and the Ki values of some ions such as Cu2+, Ni2+ and Zn2+ range from 10(-5) to 10(-6) M. Moreover, synergetic inhibitory effect of metal ions and genistein on alpha-glucosidase were studied with kinetics method. It is concluded that the inhibitory effect was much greater when both of them were added to the reactant solution simultaneously than that they were added, respectively, which suggests that the inhibitors seem to bind to the different sites of alpha-glucosidase at the same time. Furthermore, the mechanism of the synergetic inhibition was examined by spectrophotometry.

Alkannin derivatives (3-19) were prepared through the reaction of beta,beta-dimethylacrylalkannin (1), the most abundant isohexenylnaphthazarin isolated from the roots of Arnebia euchroma, with different types of nucleophiles such as amines and thiols in the absence or presence of a reducing agent. The cytotoxicities of 1-8, 10-14 and 19 against four human carcinoma cell line (GLC-82, CNE2, Bel-7402, K-562) were found to be markedly higher than that of the naturally occurring beta,beta-dimethylacrylalkannin (1) and acetylalkannin (2). This study also shed light on the understanding of the biological activities in terms of the chemical reactivity of alkannins.

The title compound, C18H14O3, also known as 1,2-di­hydro­tanshin­quinone, contains a four-ring system. No classical hydrogen bonds are found in the structure.

The structure determination of the compound C7H 9N3O4 reagent that is used in the synthesis of a class of pyschoactive drugs was investigated. It was found that the molecule of the compound was flat in the imidazole portion, but the carboxethyl group was twisted by 15.0 (1)° The compound was synthesized using a published procedure and crystals were obtained by recrystallization from diethyl ether. The structure from the x ray measurements was used for the calculation of the potential energy surface at the PM3 level using HyperChem.

In the crystal structure of the title compound, C16H18N2O4·H2O, the substituted indole mol­ecule forms a hydrogen bond to the water mol­ecule. The water mol­ecule in turn interacts with the carbonyl O atom of the acetoxy unit of an adjacent indole mol­ecule and also with the O atom of the acet­amide unit of another indole mol­ecule, giving rise to a hydrogen-bonded helical chain structure that runs along the b axis of the monoclinic unit cell.

G-quadruplex structures are a new class of attractive targets for DNA-interactive anticancer agents. The primary building block of this structure is the G-quartet, which is composed of four coplanar guanines and serves as the major binding site for small molecules. NMR studies and molecular dynamics simulations have suggested that the planarity of G-quartet surface has been highly dynamic in solution. To better investigate how the planarity of unfused aromatic ligand impacts on its quadruplex binding properties, a variety of planarity controllable isaindigotone derivatives were designed and synthesized. The interaction of G-quadruplex DNA with these designed ligands was systematically explored using a series of biophysical studies. The FRET-melting, SPR, and CD spectroscopy results showed that reducing the planarity of their unfused aromatic core resulted in their decreased binding affinity and stabilization ability for G-quadruplex. NMR studies also suggested that these compounds could stack on the G-quartet surface. Such results are in parallel with subsequent molecular modeling studies. A detailed binding energy analysis indicated that van der Waals energy (ΔE(vdw)) and entropy (TΔS) are responsible for their decreased quadruplex binding and stabilization effect. All these results provided insight information about how quadruplex recognition could be controlled by adjusting the planarity of ligands, which shed light on further development of unfused aromatic molecules as optimal G-quadruplex binding ligands.

A series of 2-phenyl-benzopyranopyrimidine (PBPP) derivatives with alkylamino side chains were synthesized and found to be a new type of highly selective ligand to bind with telomeric G-quadruplex DNA, and their biological properties were reported for the first time. Their interactions with telomeric G-quadruplex DNA were studied with FRET melting, surface plasmon resonance, CD spectroscopy, and molecular modeling. Our results showed that the disubstituted PBPP derivatives could strongly bind to and effectively stabilize the telomeric G-quadruplex structure, and had significant selectivity for G-quadruplex over duplex DNA. In comparison, the mono substituted derivatives had much less effect on the G-quadruplex, suggesting that the disubstitution of PBPP is essential for its interaction with the G-quadruplex. Furthermore, telomerase inhibition of the PBPP derivatives and their cellular effects were studied, and compound 11b was found to be the most promising compound as a telomerase inhibitor and telomeric G-quadruplex binding ligand for further development for cancer treatment.

A series of new indolizinoquinoxaline-5,12-dione derivatives were designed and synthesized via a heterocyclization reaction of 6,7-dichloroquinoxaline-5,8-dione with active methylene reagents and pyridine derivatives. The synthesized compounds exhibited significant activity to inhibit the growth of four human tumour cell lines, including lung adenocarcinoma cell, large-cell lung carcinoma cell, breast carcinoma cell, and ardriamycin-resistant breast carcinoma cell at micromolar range. These compounds were also investigated for their inhibition to DNA topoisomerase IB activity. The results indicated that the indolizinoquinoxaline-5,12-dione structure might be a potential pharmacophore in anti-cancer drug design.

The title disubstituted naphthalene-1,4-dione, C24H16Cl2O2, has the two chlorobenzyl substituents related by a non-crystallographic twofold rotation axis, generating a chiral conformation; both enantiomers are present. The two chlorobenzene rings are nearly perpendicular to the fused ring system, making angles of 88.8 (1) and 77.5 (1)° with it.

A series of novel heteropolycyclic pyrazines and oxazoles were synthesized by the reaction of 2,3-dihydrobenzo[de]chromene-7,8-dione (compound 1) with amines in mild reaction conditions. The mechanisms for these reactions were discussed.