Microwave-Assisted Synthesis of Five-Membered O-Heterocycles

Microwave-Aided Reactions of Aniline Derivatives with Formic Acid: Inquiry-Based Learning Experiments

The synthesis of amides belongs to traditional experimental tasks not only in organic chemistry exercises at universities but also at chemically focused secondary schools or in special practices at general high schools. An example of such a synthesis may be the preparation of acetanilide via reaction of aniline with acetic acid or acetic anhydride. However, both of these reactions are associated with a rather long reaction time and certain hazards that limit their straightforward use in pedagogical practice. Conveniently, the reaction of aniline with acetic acid may be significantly optimised if it is performed under solvent-free conditions in the presence of microwaves, which reduces considerably the reaction time and provides very good yield, compared to traditional heating by a heating nest. In this study, the main pedagogical aim of the experimental design is elucidation of the influence of the structure of the amines on the course of the reaction with formic acid through inquiry-based learning. Specifically, the proposed experiments consist in investigation of the chemical yield achieved in microwave assisted reactions of aniline and its derivatives with formic acid in such a way that is adequate for constructive learning of undergraduate chemistry students. The selected series of amines involves aniline, 4-methoxyaniline, 4-chloroaniline, and 4-nitroaniline. In accordance with the chemical reactivity principles, students gradually realise that the influence of the substituent is reflected in the reaction yield, which grows in the following order: N-(4-nitrophenyl)formamide ˂ N-(4-chlorophenyl)formamide ˂ N-phenylformamide ˂ N-(4-methoxyphenyl)formamide. Therefore, the results of the experiments enable students to discover that stronger basicity of the amine increases the yield of the amide. In order to deepen the students’ chemical knowledge and skills, the concept of the experiments was transformed to support inquiry-based student learning. The proposed experiments are intended for experimental learning in universities educating future chemistry teachers, but they may be also utilised in the form of workshops for students at secondary schools of a general educational nature.

New Benzimidazole-, 1,2,4-Triazole-, and 1,3,5-Triazine-Based Derivatives as Potential EGFRWT and EGFRT790M Inhibitors: Microwave-Assisted Synthesis, Anticancer Evaluation, and Molecular Docking Study

A new series of benzimidazole, 1,2,4-triazole, and 1,3,5-triazine derivatives were designed and synthesized using a microwave irradiation synthetic approach utilizing 2-phenylacetyl isothiocyanate (1) as a key starting material. All the new analogues were evaluated as anticancer agents against a panel of cancer cell lines utilizing doxorubicin as a standard drug. Most of the tested derivatives exhibited selective cytotoxic activity against MCF-7 and A-549 cancer cell lines. Furthermore, the new target compounds 5, 6, and 7 as the most potent antiproliferative agents have been assessed as in vitro EGFRWT and EGFRT790M inhibitors compared to the reference drugs erlotinib and AZD9291. They represented more potent suppression activity against the mutated EGFRT790M than the wild-type EGFRWT. Moreover, the compounds 5, 6, and 7 down-regulated the oncogenic parameter p53 ubiquitination. A docking simulation of compound 6b was carried out to correlate its molecular structure with its significant EGFR inhibition potency and its possible binding interactions within the active site of EGFRWT and the mutant EGFRT790M.

Asymmetric synthesis of new γ-butenolides via organocatalyzed epoxidation of chalcones

A greener three-step sequence, with only one single chromatographic purification, afforded γ-butenolides in moderate overall yield and high enantiomeric excess.

A new microwave-assisted thionation-heterocyclization process leading to benzo[c]thiophene-1(3H)-thione and 1H-isothiochromene-1-thione derivatives

The first example of a MW-assisted tandem thionation/S-cyclization process, leading to benzothiophenethione and isothiochromenethione derivatives, is reported.