Solvent-free sonochemical multi-component synthesis of benzopyranopyrimidines catalyzed by polystyrene supported p-toluenesulfonic acid

One-Pot Synthesis of Benzopyrano-Pyrimidine Derivatives Catalyzed by P-Toluene Sulphonic Acid and Their Nematicidal and Molecular Docking Study

A cost-effective and environmentally benign benzopyrano-pyrimidine derivative synthesis has been established with the condensation of different salicylaldehyde derivatives, piperidine/morpholine with malononitrile, in the presence of a catalyst containing p-toluene sulphonic acid (PTSA) at 80 °C temperature. This procedure offers a new and enriched approach for synthesizing benzopyrano-pyrimidine derivatives with high yields, a straightforward experimental method, and short reaction times. The synthesized compounds were investigated for their nematocidal activity, and the result shows that among the four compounds, compounds 4 and 5 showed strong nematocidal activity against egg hatching and J2s mortality. The nematocidal efficacy of the compounds might be due to the toxicity of chemicals which are soluble in ethanol. The nematocidal effectiveness was directly related to the concentration of ethanolic dilutions of the compounds, i.e., the maximum treatment concentration, the higher the nematocidal action, or the higher the mortality and egg hatching inhibition. In the present study, with support from docking analysis, the relation between chemical reactivity and nematocidal activity of compound 4 was inferred.

Ultrasound-assisted synthesis of pyrimidines and their fused derivatives: A review

The pyrimidine scaffold is present in many bioactive drugs; therefore, efficient synthetic routes that provide shorter reaction times, higher yields, and site-selective reactions are constantly being sought. Ultrasound (US) irradiation has emerged as an alternative energy source in the synthesis of these heterocyclic scaffolds, and over the last ten years there has been a significant increase in the number of publications mentioning US in either the construction or derivatization of the pyrimidine core. This review presents a detailed summary (with 140 references) of the effects of US (synergic or not) on the construction and derivatization of the pyrimidine core through classical reactions (e.g., multicomponent, cyclocondensation, cycloaddition, and alkylation reactions). The main points that were taken into consideration are as follows: chemo- and regioselectivity issues, and the results of conventional heating methods compared to US and mechanistic insights that are also presented and discussed for key reactions.

p-TsOH-Catalyzed one-pot transformation of di- and trihydroxy steroids towards diverse A/B-ring oxo-functionalization

A milder, facile, and greener transformative protocol, specifically on solid supports, to yield A-ring and/or B-ring oxo-functionalized steroids has been accomplished.

Advances in Green Organic Sonochemistry

Over the past 15 years, sustainable chemistry has emerged as a new paradigm in the development of chemistry. In the field of organic synthesis, green chemistry rhymes with relevant choice of starting materials, atom economy, methodologies that minimize the number of chemical steps, appropriate use of benign solvents and reagents, efficient strategies for product isolation and purification and energy minimization. In that context, unconventional methods, and especially ultrasound, can be a fine addition towards achieving these green requirements. Undoubtedly, sonochemistry is considered as being one of the most promising green chemical methods (Cravotto et al. Catal Commun 63: 2-9, 2015). This review is devoted to the most striking results obtained in green organic sonochemistry between 2006 and 2016. Furthermore, among catalytic transformations, oxidation reactions are the most polluting reactions in the chemical industry; thus, we have focused a part of our review on the very promising catalytic activity of ultrasound for oxidative purposes.