Discovery and SAR exploration of N-aryl-N-(3-aryl-1,2,4-oxadiazol-5-yl)amines as potential therapeutic agents for prostate cancer

Aminonitrones as highly reactive bifunctional synthons. An expedient one-pot route to 5-amino-1,2,4-triazoles and 5-amino-1,2,4-oxadiazoles – potential antimicrobials targeting multi-drug resistant bacteria

A four-component one-pot reaction proceeds very rapidly under mild conditions and gives the heterocyclic systems in good yields.

Antiproliferative 4-(1,2,4-oxadiazol-5-yl)piperidine-1-carboxamides, a new tubulin inhibitor chemotype

We discovered a new chemical class of antiproliferative agents, 4-(1,2,4-oxadiazol-5-yl)piperidine-1-carboxamides. SAR-guided optimization of the two distinct terminal fragments yielded a compound with 120 nM potency in an antiproliferative assay. Biological activity profile studies (COMPARE analysis) demonstrated that 4-(1,2,4-oxadiazol-5-yl)piperidine-1-carboxamides act as tubulin inhibitors, and this conclusion was confirmed via biochemical assays with pure tubulin and demonstration of increased numbers of mitotic cells following treatment of a leukemia cell line.

Identification of diaryl 5-amino-1,2,4-oxadiazoles as tubulin inhibitors: the special case of 3-(2-fluorophenyl)-5-(4-methoxyphenyl)amino-1,2,4-oxadiazole

The combination of experimental (inhibition of colchicine binding) and computational (COMPARE, docking studies) data unequivocally identified diaryl 5-amino-1,2,4-oxadiazoles as potent tubulin inhibitors. Good correlation was observed between tubulin binding and cytostatic properties for all tested compounds with the notable exception of the lead candidate, 3-(3-methoxyphenyl)-5-(4-methoxyphenyl)amino-1,2,4-oxadiazole (DCP 10500078). This compound was found to be substantially more active in our in vitro experiments than the monofluorinated title compound, 3-(2-fluorophenyl)-5-(4-methoxyphenyl)amino-1,2,4-oxadiazole (DCP 10500067/NSC 757486), which in turn demonstrated slightly better tubulin binding activity. Comparative SAR analysis of 25 diaryl 5-amino-1,2,4-oxadiazoles with other known tubulin inhibitors, such as combretastatin A-4 (CA-4) and colchicine, provides further insight into the specifics of their binding as well as a plausible mechanism of action.

Convenient synthesis and biological profile of 5-amino-substituted 1,2,4-oxadiazole derivatives

We describe herein a convenient straightforward synthesis of 5-amino-substituted 1,2,4-oxadiazoles, upon the reactions of amidoximes with carbodiimides, as well as their further derivatization to acetamides, in good yields. Most of the compounds exhibited in general low interaction with the stable radical 1,1-diphenyl-2-picryl-hydrazyl. Compounds 32 and 39 inhibited significantly soybean lipoxygenase. Selected compounds were screened for their in vivo anti-inflammatory activity using the carrageenin paw edema model and showed significant anti-inflammatory activity (26, 51%). The ability of the compounds to release NO in the presence of a thiol factor has been also investigated.