Considering the remarkable relevance of acetylated derivatives of phenols, alcohols, and aryl and alkyl thiols in different areas of biology, as well as in synthetic organic chemistry, a sustainable solvent-free approach to perform acetylation reactions is proposed here. Acetylation reactions are classically performed using excess of acetic anhydride (Ac2O) in solvent-free conditions or by eventually working with stoichiometric amounts of Ac2O in organic solvents; both methods require the addition of basic or acid catalysts to promote the esterification. Therefore, they usually lead to the generation of high amounts of wastes, which sensibly raise the E-factor of the process. With the aim to develop a more sustainable system, a solvent-free, stoichiometric acetylation protocol is, thus, proposed. The naturally occurring phenol, thymol, can be converted to the corresponding-biologically active-ester with good yields, in the presence of 1% of VOSO4. Interestingly, the process can be efficiently adopted to synthesize other thymyl esters, as well as to perform acetylation of alcohols and aryl and alkyl thiols. Remarkably, a further improvement has been achieved replacing Ac2O with its greener alternative, isopropenyl acetate (IPA).

Valentini, F., Galloni, P., Brancadoro, D., Conte, V., Sabuzi, F. (2022). A stoichiometric solvent-free protocol for acetylation reactions. FRONTIERS IN CHEMISTRY, 10 [10.3389/fchem.2022.842190].

A stoichiometric solvent-free protocol for acetylation reactions

Galloni P.;Conte V.;Sabuzi F.
2022-01-01

Abstract

Considering the remarkable relevance of acetylated derivatives of phenols, alcohols, and aryl and alkyl thiols in different areas of biology, as well as in synthetic organic chemistry, a sustainable solvent-free approach to perform acetylation reactions is proposed here. Acetylation reactions are classically performed using excess of acetic anhydride (Ac2O) in solvent-free conditions or by eventually working with stoichiometric amounts of Ac2O in organic solvents; both methods require the addition of basic or acid catalysts to promote the esterification. Therefore, they usually lead to the generation of high amounts of wastes, which sensibly raise the E-factor of the process. With the aim to develop a more sustainable system, a solvent-free, stoichiometric acetylation protocol is, thus, proposed. The naturally occurring phenol, thymol, can be converted to the corresponding-biologically active-ester with good yields, in the presence of 1% of VOSO4. Interestingly, the process can be efficiently adopted to synthesize other thymyl esters, as well as to perform acetylation of alcohols and aryl and alkyl thiols. Remarkably, a further improvement has been achieved replacing Ac2O with its greener alternative, isopropenyl acetate (IPA).
2022
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore CHIM/06 - CHIMICA ORGANICA
English
acetic anhydride; acetylation; alcohols; isopropenyl acetate; phenols; sustainability; thiols; thymol
Valentini, F., Galloni, P., Brancadoro, D., Conte, V., Sabuzi, F. (2022). A stoichiometric solvent-free protocol for acetylation reactions. FRONTIERS IN CHEMISTRY, 10 [10.3389/fchem.2022.842190].
Valentini, F; Galloni, P; Brancadoro, D; Conte, V; Sabuzi, F
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/308518
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