Compound 15f Research Articles

Synthesis and biological evaluation of 2-trifluoromethyl/sulfonamido-5,6-diaryl substituted imidazo[2,1- b]-1,3,4-thiadiazoles: A novel class of cyclooxygenase-2 inhibitors

A series of 2-trifluoromethyl/sulfonamido-5,6-diarylsubstituted imidazo[2,1- b]-1,3,4-thiadiazole derivatives 15a– j have been synthesized by the reaction of 2-amino-5-trifluoromethyl/sulfonamido-1,3,4-thiadiazoles 14a– b and appropriately substituted α-bromo-1,2-( p-substituted)diaryl-1-ethanones 13a– h. Structures of these compounds were established by IR, 1H NMR, 13C NMR, Mass, and HRMS data. The selected compounds were evaluated for their preliminary in vitro cyclooxygenase inhibitory activity against COX-2 and COX-1enzymes using colorimetric method. The compounds tested showed selective inhibitory activity toward COX-2 (80.6–49.4%) over COX-1 (30.6–8.6), amongst them compounds 15f and 15j showed appreciable COX-2 selective inhibitory activity. These compounds also exhibited significant anti-inflammatory activity (70.09–42.32%), which is comparable to that of celecoxib in the carrageenan-induced rat paw edema method.

Response of Rat Thoracic Aorta to F2-Isoprostane Metabolites

This study was undertaken to investigate the vascular actions (contraction and relaxation) of the F(2)-isoprostane metabolites 15-keto-15-F(2t)-IsoP, 2,3-dinor-15-F(2t)-IsoP, and 2,3-dinor-5,6-dihydro -15-F(2t)-IsoP in comparison with 15-F(2t)-IsoP on the rat thoracic aorta. 15-keto-15-F(2t)-IsoP induced a vasoconstriction in a concentration-dependent manner with a pD(2) value of 5.80 +/- 0.05, whereas 2,3-dinor-15-F(2t)-IsoP and 2,3-dinor-5,6-dihydro-15-F(2t)-IsoP had no effect. The parent compound 15-F(2t)-IsoP was more potent (pD(2) value: 6.46 +/- 0.1). Endothelium removal had no influence on the contraction to 15-keto-15-F(2t)-IsoP. GR32191 (a TP-receptor antagonist) concentration-dependently inhibited the contraction induced by 15-keto-15-F(2t)-IsoP, with a significant decrease in the E(max) values for GR32191 10(-7) M. Pretreatment with 2,3-dinor-15-F(2t)-IsoP and 2,3-dinor-5,6-dihydro-15-F(2t)-IsoP induced no alteration of 15-F(2t)-IsoP concentration-response curves. In contrast, 15-keto-15-F(2t)-IsoP pretreatment competitively inhibited the response to 15-F(2t)-IsoP. When concentration ratios of EC(50) values were used, a Schild regression of this data was linear with a slope of 0.974 and a pA(2) value of 6.13. 15-keto-15-F(2t)-IsoP at high concentrations caused a weak concentration-dependent relaxation of rat aorta rings contracted with U46619 (3.10(-8) M) that was not modified in the absence of endothelium. In contrast, 2,3-dinor-15-F(2t)-IsoP and 2,3-dinor-5,6-dihydro-15-F(2t)-IsoP induced no vasodilation. In conclusion, among the F(2)-isoprostane metabolites, 2,3-dinor-15-F(2t)-IsoP and 2,3-dinor-5,6-dihydro-15-F(2t)-IsoP did not cause vasorelaxation or vasoconstriction on the rat thoracic aorta. In contrast, 15-keto-15-F(2t)-IsoP mediates contraction through activation of TP-receptors, probably as a partial agonist, and induces a weak endothelium-independent relaxation at high concentrations.

2-Alkynyl-8-aryladenines possessing an amide moiety: their synthesis and structure–activity relationships of effects on hepatic glucose production induced via agonism of the A 2B adenosine receptor

A series of 2-alkynyl-8-aryladenine derivatives bearing an amide moiety at the 9-position of adenine was synthesized. These analogues were evaluated for inhibitory activity on N-ethylcarboxamidoadenosine (NECA)-induced glucose production in primary cultured rat hepatocytes. The m-primary benzamide derivative 15f was the most potent compound (IC 50=0.017 μM), being 15-fold more active than the corresponding 9-methyl derivative ( 1). Compound 15f showed 72- and 5.2-fold selectivity for human A 2B receptor versus human A 1 and A 2A receptors, respectively. Structure–activity relationship (SAR) studies of the synthesized compounds indicated that a three-carbon linker, fixed in the form of a benzene ring, between the adenine core and the amide moiety is important for both A 2B antagonistic activity and selectivity. The IC 50 values in rat hepatocyte glucose assay correlated well with the IC 50 values in cAMP assay using Chinese hamster ovary cells stably transfected with human A 2B receptors ( r 2=0.94). The A 1 and A 2A affinities showed no correlation with the potency to inhibit NECA-induced glucose production. These results strongly support our previous conclusion that adenosine agonist-induced hepatic glucose production in rat hepatocytes is mediated through the A 2B receptor.

Discovery and synthesis of a potent sulfonamide ET B selective antagonist

The synthesis and structure–activity relationships of a series of sulfonamide endothelin antagonists are described. In the course of our modification studies, we discovered ET B selective antagonists. The most potent compound 15f displays IC 50 values of 1.7 μM and 0.002 μM to ET A and ET B receptors, respectively.

Synthesis and antitumor activity of duocarmycin derivatives: modification of segment-A of A-ring pyrrole compounds.

A series of 3-substituted A-ring pyrrole compounds of duocarmycin were synthesized and evaluated for in vitro anticellular activity against HeLa S(3) cells and in vivo antitumor activity against murine sarcoma 180 in mice. These compounds were evaluated on the peripheral blood toxicity and delayed lethal toxicity. Further, to expand our investigation of their peripheral blood toxicity, the toxicity to bone marrow cells (CFU-GM, CFU-Meg) was investigated. Among 3-substituted A-ring pyrrole compounds of duocarmycin bearing a 5',6',7'-trimethoxy-2'-indolecarboxyl group as segment-B (Seg-B), several analogues showed remarkably potent antitumor activity with low peripheral blood toxicity. The 3-formyl compound 12h, one of such analogues, showed stronger antitumor activity with lower toxicity to bone marrow cells compared to DU-86 (2a), an active metabolite of KW-2189 (2b). However, compound 12h caused delayed death. On the other hand, the 3-bromo compound 15f, one of the 3-substituted A-ring pyrrole derivatives bearing a 4'-methoxycinnamoyl group as Seg-B, showed the most potent antitumor activity among the 4'-methoxycinnamate analogues with low toxicity to bone marrow cells. Furthermore, compound 15f did not cause delayed death similarly to 2d. These results would indicate the importance of the C-3 substituents of A-ring pyrrole duocarmycin derivatives for exhibiting antitumor activity and decreasing toxicity.