Microwave‐Assisted Synthesis and Biological Evaluation of Some New Pyrazolothiazoles via a Multicomponent Approach

Abstract

A series of new pyrazolothiazole hybrids were designed and synthesized by the microwave‐assisted multicomponent reaction of thiosemicarbazide, 3‐(furan‐2‐yl)‐1‐(pyridin‐2‐yl)prop‐2‐en‐1‐one and 1‐(pyridin‐2‐yl)‐3‐(thiophen‐2‐yl)prop‐2‐en‐1‐one with substituted 2‐bromoacetophenones. Structures of all the synthesized compounds were in good agreement with their spectral (FTIR, 1H & 13C NMR, Mass) and analytical data (CHN analysis). The target compounds were screened for their in vitro cytotoxic activity by testing against human adenocarcinoma (A549), cervical cancer (HeLa), human neuroblastoma (SK−N‐SH) and human prostate cancer (DU‐145) cell lines. From the in vitro results, it was found that the compound derived from p‐ NO2 phenyl (4 h) has potent activity against HeLa cell line with IC50 value 9.97 ± 0.05 μM. Also, the compounds having p‐OCH3 phenyl (4 c), phenyl (4 i), and p‐Cl phenyl (4 j) substitutions exhibited significant activity against HeLa cell line with IC50 values 19.78 ± 0.03 μM, 18.47 ± 0.01 μM and 15.61 ± 0.06 μM respectively.

Development in the Synthesis of Bioactive Thiazole-Based Heterocyclic Hybrids Utilizing Phenacyl Bromide

“…The diverse range of pharmacological effects displayed by furans underscore their potential significance in the formulation of pharmaceutical agents endowed with multifaceted therapeutic applications (Figure 10). 54 Mamidala and his research team 55 developed a microwavemediated, single-step methodology for the synthesis of several furan hybrids designed as potent anticancer agents, 22a−22l, with exceptional yields. The multicomponent synthesis involved the cyclization of phenacyl bromide 7 with thiosemicarbazide 20, followed by the reaction of chalcone 21 with a catalytic amount of sodium hydroxide (NaOH) in ethanol at 70 °C for 5 to 6 min, resulting in the production of the desired compounds.…”

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

“…Menéndez and co-workers [138] described an efficient microwave-assisted sequential four-component reaction of chalcones 157, acyclic 1,3-diketone 54, butylamine (158) and ammonium formate (159) using CAN as a catalyst and ethanol as solvent. This is followed by sequential addition of formamide (160) under microwave irradiation to yield polysubstituted 5,6-dihydroquinazolinones 161 in good to moderate yields (Scheme 64).…”

“…Recently, Vedula and co-workers [158] designed a facile and efficient base-catalyzed microwave-assisted three-component reaction between thiosemicarbazide (191), substituted chalcones 157 with substituted phenacyl bromides 41 in EtOH for the construction of pyrazolothiazoles 192. A comparative study of the conventional refluxing method with the microwaveassisted protocol depicted the efficiency of microwave technology in increasing the yield from 82% to 95% in reduced time from 4 h to 5 min.…”

Ultrasound-Assisted Synthesis and Characterization of 5-Carbonitrile-Functionalized tetrahydropyrimidine Derivatives with Evaluation of Their Antimicrobial Activity

“…21 Developing MCR processes in aqueous medium is an active field of study in this direction has several benefits, including the absence of carcinogenic effects, 22 decreased pollution, lesser cost, and ease of processing, which are beneficial to both the industry and the environment. 23 Additionally the synthesis 24 of several organic compounds with the aid of ultrasonic technology and the presence of catalysts greatly increase reaction rate 25 , reduced reaction durations, decreased energy consumption 26 , increased selectivity, and increased product yield. Compared to traditional procedures, these procedures have revealed to be effective, rapid, clean 27 , environmentally friendly, and reliable in chemical laboratory.…”