Design, synthesis, SAR and ADMET analyses of the novel class of synthetic 7-amino[1,2,5]oxadiazolo[3,4-b]pyridine-6-carboxylate derivatives with vasorelaxant activity

• The method of synthesis of furazano[3,4- b ]pyridine derivatives has been improved. • The potential vasodilator activity of furazanopyridine derivatives has been studied. • Eight derivatives showed high vasorelaxant activity. • Some corelations between the structure and activity of compounds have been established. A twenty six 7-amino[1,2,5]oxadiazolo[3,4-b]pyridine-6-carboxylate (7-aminofurazano[3,4-b]pyridine-6-carboxylate) derivatives have been synthesized and characterized by IR, 1 H NMR, 13 C NMR spectroscopy, elemental analysis and LC-MS. The potential vasodilator activity of the synthesized compounds was assessed for their ability to induce relaxation of phenylephrine-precontracted isolated rat aortic segments. Eight derivatives showed high vasorelaxant activity, ranging from 73.7 to 87.3 %. Six samples contained an ethyl carboxylate moiety at the 6th position and alkyl or cycloalkyl substituents at the 5th position. Moreover, in the series of compounds with n-alkyl and cycloalkyl substituents, the derivative activity decreased linearly as the number of carbon atoms diminished. ADMET analysis showed that the highly active derivatives met the requirements for drug candidates regarding bioavailability, physicochemical and pharmacokinetic properties. These compounds are also approved by all the filters used, such as druglikeness and leadlikeness. The only problematic property of these highly active vasorelaxants is their in silico predicted very high carcinogenicity, which may be incompatible with their long-term use. Seven derivatives exhibited high virtual similarity to acetylcholinesterase inhibitors, with scores in the range of 0.857 to 0.932. This suggests that they may increase acetylcholine levels, thereby reducing vascular tone. However, this requires experimental confirmation. It should be noted that some 7-aminofurazano[3,4-b]pyridine-6-carboxylate analogs showed a high similarity to inhibitors of adenosine receptors, the non-receptor protein tyrosine kinases JAK2 and JAK3, glycogen synthase kinase-3 beta, prostaglandin E synthase and arachidonate 5-lipoxygenase, providing a basis for direct virtual assessment of their interaction with these targets. The results obtained highlight the considerable potential for further development of this class of compounds as vasoactive agents.