Synthesis and Potential Muscarinic Receptor Binding and Antioxidant Properties of 3-(Thiadiazolyl)pyridine 1-Oxide Compounds

Abstract

The synthesis of two different series of 3‐(thiadiazolyl)pyridine 1‐oxides containing 1,2,5‐ and 1,2,4‐thiadiazole moiety respectively is described. The potential muscarinic receptor binding together with the antioxidant properties of the new compounds were evaluated.

Synthesis and anticholinesterase activities of novel 1,3,4-thiadiazole based compounds

“…Some researchers have studied thiadiazoles extensively and the compounds bearing thiadiazole moiety have been reported to exhibit significant anticholinesterase activity 11,12 . The antioxidant and muscarinic receptor binding properties of 3-(thiadiazolyl)pyridine 1-oxides were reported by Martinez et al 13 . as potential acetylcholinesterase inhibitors.…”

“…In the case of additional substitution in position 5 by chlorine atom protons of that ring appear as two characteristic singlets at ca. 6.7 and 8 ppm corresponding to H-C(2) and H-C(5), respectively [13][14][15][16] . Singlet is registered for H-C(isoxazole) at 7.88 ppm in the case of compound 10.…”

“…7.77 and 7.63 ppm with J = 3.9 Hz (11,12) . In the relatively strong band corresponding to tropylic cation C 7 H 7 + (m/z 91) is observed for benzyl derivative 13 . It is the effect of α and β atoms disconnection in relation to the phenyl ring.…”

“…The presence of the additional heterocyclic ring (oxazolyl, thiophenyl) does not improve activities of compounds. Placement of chlorine atom in the benzenodiole moiety does not change substantially affinity of compounds for both enzymes (13)(14)(15)(16) . The analogs possessing naphthalenyl (3) or biphenylyl (12) substituent are inactive.…”

“…HO-C(3)), 10.49 (s, 1H, NH), 7.98 (m, 1H, H-C(5)), 7.95 (t, 1H, J = 1.93 Hz, H-C(2')), 7.47 (m, 1H, H-C(6')), 7.37 (t, 1H, J = 8.10 Hz, H-C(5')), 7.04 (m, 1H, H-C(4')), 6.70 (s, 1H, H-C(2)); 13 C NMR (125 MHz, DMSO-d 6 178 (6), 177 (18), 164 (18), 163 (7), 150 (9), 148 (17), 147 (12), 146 (72), 145 (100), 132 (9), 131 (9), 129 (11), 121 (9), 120 (11), 104 (7), 102 (13), 91 (5), 77 (7), 51 (6), 45 (13), 44 (23), 42 (11), 39 (6), 36 (27), 34 (11).…”