Novel Synthetic Dopamine Analogues: Carbon-13/Nitrogen-15 Isotopic Labeling and Fluorescence Properties

Abstract

Dopamine (DA) and its analogues are compounds of interest in polymer science where their properties provide a multitude of applications. However, in elucidating polydopamine structure, there are ambiguities related to the types of bonds, the structure of monomeric units, their ratio, and influence of synthesis parameters. In order to minimize these variables, isotopic labeling presents an optimal alternative. In the diversification and understanding of these polymers, we aim to investigate analogues that by selective isotopic labeling provide possibilities for structure elucidation both of the polymerized analogues as well as polydopamine. In the present paper we report the synthesis of three new dopamine derivatives, labeled *CL ((Z)-3-(3,4-bis(benzyloxy)phenyl)-2-cyano-2-propenamide) and both labeled and unlabeled DL/*DL (2-aminomethyl-3-(3,4-dihydroxyphenyl)propionamide). The labeled *CL and *DL compounds contain selective ¹³C and ¹⁵N labeling in the alkyl chain. For these new compounds, NMR, FT-IR and fluorescence characterization, including by time-resolved laser spectroscopy, are reported.

Keywords:

• carbon-13/nitrogen-15 isotopic labeling
• dopamine analogues
• fluorescence
• nuclear magnetic resonance (NMR)

Acknowledgement

The authors acknowledge Dr. Ramona Suciu for conducting the steady-state fluorescence spectroscopy.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the Romanian Ministry of Research under Core Program, Project PN19 35 01 02.