Tryptophan methyl ester: a proposal of the thermal decomposition mechanism

• Published in: Journal of thermal analysis and calorimetry Vol. 147; no. 14; pp. 7741 - 7748
• Main Authors: Justino, A., Carvalho, A. C. S., de Vasconcelos, L. G., Gai, B. M., Stein, A. L., Siqueira, A. B.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-07-2022; Springer; Springer Nature B.V
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Decomposition; Differential thermal analysis; Inorganic Chemistry; Mass spectrometry; Measurement Science and Instrumentation; Metabolites; NMR; Nuclear magnetic resonance; Physical Chemistry; Physiological aspects; Polymer Sciences; Synthesis; Thermal decomposition; Thermodynamic properties; Tryptamines; Tryptophan; Thermal decomposition mechanism; Tryptophan methyl ester; Molecular modeling; Thermal behavior
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-021-11089-3

Tryptophan (Trp) is a secondary metabolite derived from the shikimate pathway responsible for the synthesis of several alkaloids in some animals and plants. In mammalian metabolism, Trp participates in several biological functions and has a wide application in drug synthesis. In this work, Trp was used as a starting material for the synthesis of its methyl ester derivative. This compound was characterized by the NMR
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H e
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C, FTIR, TG–DTA, TG–DSC coupled to FTIR, and HPLC/MS techniques. The preliminary tests showed a formation of the tryptophan methyl ester (Z3) as the main product. The thermal behavior of Z3 showed significant changes when compared to its precursor. From the data obtained through thermoanalytical techniques, it was possible to determine a thermal decomposition mechanism for tryptophan methyl ester, as well as isolating and characterizing the intermediary obtained in the first thermal decomposition step, tryptamine. Compound Z3 and intermediate compounds from its thermal decomposition were optimized by molecular modeling, and the theoretical FTIR spectrum of the compounds showed a good correlation with experimental data.