Guowu Lin

Synthesis, structure, DNA binding and cleavage ability of a new copper ciprofloxacin complex

The structure of 1 consists of [Cu(HCp)(phen)(H2O)]2+ (HCp is ciprofloxacin and phen is 1,10-phenanthroline), two acetates, and four free water molecules. In each cation, copper displays a distorted square pyramid, coordinated to ring 3-carboxylate and 4-oxo oxygen from HCp, two nitrogens from phen, and one water molecule. There are five water molecules in each discrete complex with one coordinated to Cu center, and the other four linked to each other by intermolecular hydrogen bonds. Two uncoordinated acetates make the compound neutral. The complex exhibits higher DNA binding compared to HCp at the same conditions by fluorescence and viscosity measurements. Combining its structure with the DNA-binding result, the binding mechanism may be explained by intercalation. Moreover, 1 shows significant cleavage of DNA in the presence of a reducing agent, such as ascorbate by gel electrophoresis using supercoiled pBR322 DNA in Tris-HCl buffer (pH 7.4). The complex also has a higher activity against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Klebsiella pneumoniae than HCp.

Design, synthesis and biological evaluation of β-carboline derivatives as novel inhibitors targeting B-Raf kinase.

β-Carboline family of compounds is a large group of alkaloids widely distributed in nature and exhibits broad-spectrum anti-tumor activities. We designed and synthesized two series of novel 1-carboxamide- and 6-sulfonamide-substituted β-carboline derivatives 7a-p and 12a-b, and their wild type B-Raf kinase inhibitory activities were described. Most compounds showed moderate to excellent inhibitory activities. Among them, 1-carboxamide-6-(N-(3-(dimethylamino)propyl)-sulfamoyl)-β-carboline, 7e exhibited potent activity (IC(50)=1.62 μM), showing the potential for further investigation as a lead compound.

A selectivity study on mTOR/PI3Kα inhibitors by homology modeling and 3D-QSAR

The phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway plays a critical role in the regulation of cellular growth, survival and proliferation. mTOR and PI3K have attracted particular attention as cancer targets. These kinases belong to the phosphatidylinositol-3-kinase-related kinase (PIKK) family and therefore have considerable homology in their active sites. To accelerate the discovery of inhibitors with selective activity against mTOR and PI3K as cancer targets, in this work, a homology model of mTOR was developed to identify the structural divergence in the active sites between mTOR and PI3Kα. Furthermore, two highly predictive comparative molecular similarity index analyses (CoMSIA) models were built based on 304 selective inhibitors docked into mTOR and PI3Kα, respectively (mTOR: q2 = 0.658, rpre2 = 0.839; PI3Kα: q2 = 0.540, rpre2 = 0.719). The results showed that steric and electrostatic fields have an important influence on selectivity towards mTOR and PI3Kα—a finding consistent with the structural divergence between the active sites. The findings may be helpful in investigating selective mTOR/PI3Kα inhibitors.

A Facile Synthesis of 3-Substituted 9H-Pyrido[3,4-b]indol-1(2H)-one Derivatives from 3-Substituted β-Carbolines

A mild and efficient two-step synthesis of 3-substituted β-carbolinone derivatives from 3-substituted β-carboline in good yields is described. A possible reaction mechanism for the formation of the skeleton of β-carbolin-1-one is proposed. The structures of these compounds were established by IR, 1H-NMR, 13C-NMR, mass spectrometry and elemental analysis, as well as X-ray crystallographic analysis of 4-2 and 6-2.

De novo design of quinazoline derivatives as CDK2 inhibitors: 3D-QSAR, molecular fragment replacement and Volsurf predictions

Cyclin-dependent kinase 2 (CDK2) has appeared as an important drug target over the years with a multitude of therapeutic potentials. To design compounds with enhanced inhibitory potencies against CDK2, 3D-QSAR and molecular fragment replacement studies were performed on the pyrazolo[4,3-h]quinazoline derivatives, a class of potent CDK2 inhibitors. The contours of 3D-QSAR model revealed important structural features of the inhibitors related to the active site of CDK2. Based on the pyrazolo[4,3-h]quinazoline core, the different substituents at three important points were replaced with diverse molecular fragments. The compounds resulting from fragments assembly with pyrazolo[4,3-h]quinazoline core were then scored with the robust 3D-QSAR model. Furthermore, the absorption, distribution, metabolism and excretion properties of these compounds were predicted by Volsurf to eliminate inappropriate compounds. Thirty-one new potential compounds were finally obtained. These results initiated us to further optimise and design new potential inhibitors.

Discovery of 4-((7H-Pyrrolo[2,3-d]pyrimidin-4-yl)amino)-N-(4-((4-methylpiperazin-1-yl)methyl)phenyl)-1H-pyrazole-3-carboxamide (FN-1501), an FLT3- and CDK-Kinase Inhibitor with Potentially High Efficiency against Acute Myelocytic Leukemia

A series of 1-H-pyrazole-3-carboxamide derivatives have been designed and synthesized that exhibit excellent FLT3 and CDK inhibition and antiproliferative activities. A structure-activity-relationship study illustrates that the incorporation of a pyrimidine-fused heterocycle at position 4 of the pyrazole is critical for FLT3 and CDK inhibition. Compound 50 (FN-1501), which possesses potent inhibitory activities against FLT3, CDK2, CDK4, and CDK6 with IC50 values in the nanomolar range, shows antiproliferative activities against MV4-11 cells (IC50: 0.008 μM), which correlates with the suppression of retinoblastoma phosphorylation, FLT3, ERK, AKT, and STAT5 and the onset of apoptosis. Acute-toxicity studies in mice show that compound 50 (LD50: 186 mg/kg) is safer than AT7519 (32 mg/kg). In MV4-11 xenografts in a nude-mouse model, compound 50 can induce tumor regression at the dose of 15 mg/kg, which is more efficient than cytarabine (50 mg/kg). Taken together, these results demonstrate the potential of this unique compound for further development into a drug applied in acute-myeloid-leukemia (AML) therapeutics.

A Facile Synthesis of 1-Substituted β-Carboline Derivatives via Minisci-Reaction

Abstract A mild and efficient one-pot reaction for the synthesis of 1-substituted β-carboline derivatives via the Minisci reaction has been developed with good yields and selectivity. In addition, the mechanism of the 1-substituted β-carboline derivatives by means of the nucleophilic radical is described.

Synthesis of a Novel Series of 1,6-Disubstituted-3-(cyclohexylmethoxy)-β-carboline Derivatives via Minisci Reaction

Abstract A facile and efficient route for the synthesis of 1,6-disubstituted-3-cyclohexylmethoxy-β-carboline derivatives via the Minisci reaction has been described with good yields and selectivity. A novel series of β-carboline derivatives with various substituents at 1-, 3-, and 6-positions were designed and synthesized from the starting material (±)-tryptophan on the basis of harmine chemical structure. The mechanism of the 1-substituted β-carboline derivatives by means of a nucleophilic radical was also described, and the x-ray analysis confirmed the structures of 11-7. GRAPHICAL ABSTRACT

(N-{[4-(1,3-Benzothiazol-2-yl)anilino]carbonylmethyl-κO}iminodiacetato-κ3O,N,O′)(1,10-phenanthroline-κ2N,N′)cobalt(II) pentahydrate

The title compound, [Co(C(19)H(15)N(3)O(5)S)(C(12)H(8)N(2))] x 5 H(2)O, has a moderately distorted octahedral coordination environment composed of two N atoms of a 1,10-phenanthroline ligand and one N and three O atoms of an N-{[4-(1,3-benzothiazol-2-yl)anilino]carbonylmethyl}iminodiacetate (ZL-5(2-)) ligand. The ring systems of the phenanthroline and ZL-5(2-) ligands are coplanar and the complexes pack in layers parallel to the ab plane with the rings of adjacent complexes facing one another. The layers stack along the c axis and are linked by hydrogen bonds involving the five water solvent molecules in the asymmetric unit and O atoms of the acetate groups of the ZL-5(2-) ligand. This is believed to be the first crystal structure of a complex of a 2-(4-aminophenyl)benzothiazole ligand.

(N-{[4-(1,3-benzothiazol-2-yl)anilino]carbonylmethyl-kappaO}iminodiacetato-kappa(3)O,N,O')(1,10-phenanthroline-kappa(2)N,N')cobalt(II) pentahydrate.

The title compound, [Co(C(19)H(15)N(3)O(5)S)(C(12)H(8)N(2))] x 5 H(2)O, has a moderately distorted octahedral coordination environment composed of two N atoms of a 1,10-phenanthroline ligand and one N and three O atoms of an N-{[4-(1,3-benzothiazol-2-yl)anilino]carbonylmethyl}iminodiacetate (ZL-5(2-)) ligand. The ring systems of the phenanthroline and ZL-5(2-) ligands are coplanar and the complexes pack in layers parallel to the ab plane with the rings of adjacent complexes facing one another. The layers stack along the c axis and are linked by hydrogen bonds involving the five water solvent molecules in the asymmetric unit and O atoms of the acetate groups of the ZL-5(2-) ligand. This is believed to be the first crystal structure of a complex of a 2-(4-aminophenyl)benzothiazole ligand.