%Greenness, a new metric to assess solvents

TOVAR, JOHN J.; ESPECHE, M. JULIETA; GALVÁN, MARÍA C.; ROSSI, LAURA I.

Sustainable Chemistry and Pharmacy

ELSEVIER B.V

Año: 2025 vol. 44

2352-5541

even solvents (green and non-green) were used in the nitration and α-halogenation reactions.The parameters "% Greenness" (%G) and “% Price-Affected Greenness” (%PAfG) are proposed forsolvent analysis. Partial conversion of benzothiophene to the expected nitro compounds wasobserved when the reaction was carried out at reflux in dimethylcabonate (60.5%G) or acetic acid(36.8%G). However, in dichloromethane (39.5%G) where there was higher substrate conversion,the reaction was not chemoselective. In the case of cinammic acid, β-nitrostyrene was observedwhen the nitration reaction was carried out at reflux in dimethylcarbonate or acetonitrile (42.1%G). In ethyl acetate (65.8%G) and dichloromethane, cinnamic acid did not react and, in cyclopentyl methyl ether (31.6%G), by-products of the solvent were observed. Finally, in the halogenation reaction, the best solvent to obtain α-bromopropiophenone was ethyl acetate. Allreactions were analysed with different green metrics such as