Palladium-catalyzed carbonylation reaction has surfaced as a robust tool for insertion of the carbonyl group into organic molecules, and in the last decades enormous progress has been made. Nowadays, a plethora of methodologies is available to synthesize all kinds of carbonyl compounds. However, the focus has shifted during recent years to address rising concerns related to developing safe, cost-efficient, and more sustainable methodologies. The use of different carbon monoxide (CO) precursors/sources, avoiding handling of highly toxic and flammable gaseous carbon monoxide, and substituting nonrenewable solvents for those derived from renewable feedstock have contributed to aim these goals. In this review, we will discuss the advent of the application of renewable solvents to improve the sustainability and environmentally benign nature of Pd catalyzed carbonylation reactions.

This work aims the synthesis of amidino pyrazolines by the cyclocondensation reaction between 3-(hetero)aryl-1-(2-hydroxyphenyl)enones and aminoguanidine hydrochloride under sonochemical conditions. Thirteen new compounds were synthesized in 15-83% of yield after sonication for 30 min without purification by chromatography. Furthermore, antimicrobial activities of the synthesized compounds were investigated by in vitro minimum inhibitory concentration (MIC) in a panel of four bacterial strains and four Candida yeasts. As result, the 5-(4-bromophenyl)-3-(2-hydroxyphenyl)-4,5-dihydro-1H-pyrazole-1-carboximidamide hydrochloride was identified as the most active against gram-positive S. aureus and E. faecalis with MIC of 7.8 µg mL−1, similar to the value showed by chloramphenicol, which was used as standard.