Guo-Gang Tu

The synthesis and preliminary activity assay In Vitro of peptide-like derivatives as APN inhibitors

Both the aminopeptidase N (APN) and matrix metalloproteinase (MMP) are essential metallopeptidases in the development of tumor invasion and angiogenesis. A series of novel peptide-like derivatives were designed and synthesized as antitumor agents. Their structures were confirmed by IR, MS, and 1H-NMR. These compounds exhibited potent inhibitory activities against APN and low activity against MMP in vitro. The derivatives with methoxy group show better activities than those with other substituted group and could be used as lead compounds for exploring new APN inhibitors in the future.

Design, synthesis and biological evaluation of CB1 cannabinoid receptor ligands derived from the 1,5-diarylpyrazole scaffold

The CB1 receptor belongs to the G-protein-coupled receptor superfamily. CB1 antagonism has been considered as a new therapeutic target for the treatment of obesity. In this study, we report the synthesis and in vitro binding affinity assay of some 1,5-diarylpyrazole scaffold compounds. The binding results showed that some of the target compounds had an excellent potency toward the CB1 receptor with IC50 values lying at the nanomole level.

4-Chloro-N-[3-methyl-1-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)but-yl]benzamide.

In the title compound, C14H16ClN3O2S, the dihedral angle between the 4-chlorophenyl and 1,3,4-oxadiazole rings is 67.1 (1)° and the orientation of the amide N—H and C=O bonds is anti. In the crystal, molecules are linked by N—H⋯O and N—H⋯S hydrogen bonds.

(2R)-N-[5-(4-Chloro­phen­yl)-1,3,4-thia­diazol-2-yl]-2-(cinnamoylamino)propanamide

In the title compound, C20H17ClN4O2S, the dihedral angle between the two benzene rings is 65.9 (1)°; the corresponding angle between the 4-chlorophenyl and thiadiazole rings is 3.4 (8)°. The conformations of the N—H and C=O bonds are anti with respect to each other. The enone groups show a trans configuration. The structure displays intermolecular N—H⋯O, C—H⋯N, C—H⋯S and C—H⋯O hydrogen bonding.

(2R)-2-Cinnamoylamino-N-[5-(4-methoxy-phen-yl)-1,3,4-thia-diazol-2-yl]propanamide.

The asymmetric unit of the title compound, C21H20N4O3S, contains two independent molecules. The dihedral angles between the two benzene rings are 47.6 (1) and 30.2 (1)°, the corresponding values between the p-methoxybenzene and thiadiazol rings are 12.3 (1) and 24.7 (1)°, respectively, for the two molecules. The conformations of the N—H and C=O bonds are anti with respect to each other. The enone groups show a trans configuration. The crystal structure is stabilized by N—H⋯O and N—H⋯N interactions. The absolute structure could not be determined from the X-ray data but the absolute configuration has been assigned by reference to an unchanging chiral centre in the synthetic procedure.

Exploring ligand dissociation pathways from aminopeptidase N using random acceleration molecular dynamics simulation

AbstractAminopeptidase N (APN) is a zinc-dependent ectopeptidase involved in cell proliferation, secretion, invasion, and angiogenesis, and is widely recognized as an important cancer target. However, the mechanisms whereby ligands leave the active site of APN remain unknown. Investigating ligand dissociation processes is quite difficult, both in classical simulation methods and in experimental approaches. In this study, random acceleration molecular dynamics (RAMD) simulation was used to investigate the potential dissociation pathways of ligand from APN. The results revealed three pathways (channels A, B and C) for ligand release. Channel A, which matches the hypothetical channel region, was the most preferred region for bestatin to dissociate from the enzyme, and is probably the major channel for the inner bound ligand. In addition, two alternative channels (channels B and C) were shown to be possible pathways for ligand egression. Meanwhile, we identified key residues controlling the dynamic features of APN channels. Identification of the dissociation routes will provide further mechanistic insights into APN, which will benefit the development of more promising APN inhibitors. Graphical AbstractThe release pathways of bestatin inside active site of aminopeptidase N were simulated using RAMD simulation

(2R,3R)-N-(4-Chloro-phen-yl)-2,3-dihydr-oxy-N'-(5-phenyl-1,3,4-thia-diazol-2-yl)succinamide.

In the structure of the title compound, C18H15ClN4O4S, the dihedral angle between the two benzene rings is 1.4 (3)°. The angle between the phenyl ring and thiadiazole ring is 5.8 (4)°. The conformations of the N—H and C=O bonds are anti with respect to each other. In the crystal structure, molecules are linked by intermolecular O—H⋯N, N—H⋯O and O—H⋯O hydrogen bonds, forming a three-dimensional network.

1-(3-Chloro­benz­yloxy)urea

The asymmetric unit of the crystal structure of the title compound, C8H9ClN2O2, contains four independent molecules. The dihedral angles between the urea N—(C=O)—N planes and the benzene rings are 83.3 (3), 87.8 (1), 89.1 (1) and 17.5 (2)° in the four molecules. Extensive N—H⋯O hydrogen bonding is present in the crystal structure.

2-Benzoyl-amino-N-[5-(4-bromo-phen-yl)-1,3,4-thia-diazol-2-yl]ethanamide.

In the structure of the title compound, C17H13BrN4O2S, the dihedral angle between the two benzene rings is 38.5 (1)°; the angle between the 4-bromobenzene and thiadiazole rings is 1.3 (1)°. The conformations of the N—H and C=O bonds are anti with respect to each other. The structure displays intermolecular N—H⋯O and C—H⋯O hydrogen bonding, with both interactions leading to inversion dimers.