Abstract: Background: In recent years, microwave radiation has been widely used in organic synthesis, including solvent-free mode. However, the reaction conditions of phthalic anhydride with amino acids under solvent-free microwave activation have not been studied so far. Objective: In the present work, the effect of microwave activation on the interaction of phthalic anhydride with amino acids in solvent-free conditions has been studied in detail. Methods: The microwave heating dynamics of phthalic anhydride, glycine and their equimolar mixture under microwave conditions have been investigated, and the dependence of the heating rate on the microwave power is defined. Results: The common conditions for the synthesis of phthaloylamino acids have been determined as continuous heating at a power of 200 W at 130 °C for 5-6 min and additional heating for 5-10 min at a temperature close to the melting point of the corresponding amino acid. We have applied the developed two-step solvent-free microwave reaction protocol successfully for the synthesis of phthaloyl derivatives of glycine, alanine, β-alanine, 4-aminobenzoic acid, γ-aminobutyric acid, isoleucine, leucine, phenylalanine. Conclusion: Reaction conditions for synthesizing phthaloylamino acids by microwave activation without solvent have been established. The solvent-free microwave reaction between phthalic anhydride and amino acid has been found to proceed in the melted phthalic anhydride.

Cite: Pankrushina N.A. , Korotkikh M.O. , Mikheev A.N.
Effect of Microwave Radiation on the Solvent-free Synthesis of Phthaloylamino Acids
CURRENT MICROWAVE CHEMISTRY. 2023. V.10. N1. P.60-65. DOI: 10.2174/2213335610666230523114340 WOS РИНЦ

Dates:

Submitted:	Feb 7, 2023
Accepted:	Apr 18, 2023
Published online:	Jul 11, 2023

Identifiers:

Web of science	WOS:001050463000007
Elibrary	62926316
OpenAlex	W4378379631

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