Catechol reactivity: Synthesis of dopamine derivatives substituted at the 6-position

Dopamine is a ubiquitous neurotransmitter essential in the proper functioning of the human body. In addition to this critical role, the catecholamine core has shown utility as a scaffold for numerous drugs and in other applications, like metal detection and adhesive materials. Substituents at the 6-position of dopamine's catechol core can modulate its stereoelectronic properties, the acidity of its phenolic hydroxyl groups, and the overall hydrophobicity of the molecule. Herein, we report the synthesis of a series of four novel dopamine analogues substituted at the 6-position of catechol core. The H-1 NMR chemical shift of the aromatic proton meta to the substituent correlated strongly with the Hammett sigma(m) constant, confirming the electronic properties of substituents.