Ultrasound‐Mediated Synthesis of New (Piperazine‐Chromene)‐Linked Bis(thieno[2,3‐b]pyridine) Hybrids as Potential Anti‐acetylcholinesterase

Abstract

Using ultrasound irradiation and the eco-friendly piperazine, two series of (piperazine-chromene)-linked bis (thieno[2,3b]pyridine) hybrids attached to various arene or chromene units were efficiently prepared. Therefore, the target hybrids were prepared by reacting bis(pyridine-2(1H)-thione) with two equivalents of the appropriate α-haloketones in the presence of 1.4 equivalents of piperazine. The reaction mixture was subjected to ultrasonic irradiations at 60 °C for 20-40 min to produce the desired products in 87-96 % yields. At concentrations of 15 and 25 μM, new hybrids were tested for antiacetylcholinesterase activity, as well as their ability to quench DPPH free radicals at a concentration of 25 μg/mL. Generally, the chromene unit attached to thienopyridine-C2 has a significant effect on the inhibitory activity of the new hybrids. Moreover, the electronic properties of the substituent attached to the chromene-C6 unit influence the inhibitory activity. The bis(thienopyridine) hybrid attached to 6-methoxy-2H-chromen-2-one units demonstrated the best anti-acetylcholinesterase activity at the previous concentrations, with inhibition percentages of 69.1 and 85.4. Additionally, with an inhibition percentage of 84.4, the previous hybrid demonstrated the most effective anti-DPPH activity.

New Arylazo‐Based (Chromene‐Thiazole) Hybrids as Potential MRSA Inhibitors

“…With the goal of synthesizing new chromene and thiazole‐based compounds with promising bioactivity, particularly antibacterial activity, [46–50] we aimed to study the impact of arylazo units on the antibacterial activity of new chromene‐thiazole hybrids. Using a three‐component protocol, we prepared hybrid 1 and new hybrids 2 – 4 with arylazo units attached to chromene‐C6 and/or thiazole‐C5 (see Figure 2).…”