Synthesis, antioxidant, and antiacetylcholinesterase activities of sulfonamide derivatives of dopamine-related compounds.

A series of sulfonamides were synthesized from dopamine derivatives. The reactions of amines with methanesulfonyl chloride followed by O-demethylation with BBr3 afforded phenolic sulfonamides. The antioxidant activities of the synthesized phenolic sulfonamides were investigated by thiocyanate method, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(•+)), 1,1-diphenyl-2-picryl-hydrazyl (DPPH(•)), N,N-dimethyl-p-phenylenediamine (DMPD(•+)), and superoxide anion (O2(•-)) radical scavenging, reducing power, and ferrous ion (Fe(2+)) chelating assays. Sulfonamides 13-16 showed around 75-85% inhibition on linoleic acid peroxidation. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol, and trolox indicated an inhibition of 90.0%, 85.73%, 73.33%, and 85.73% on peroxidation, respectively, in the same system at the same concentration (10 µg/mL). Also, the inhibition effects of the synthesized compounds on acetylcholinesterase (AChE) activity were evaluated. AChE was effectively inhibited by sulfanomides 13-16, with K(i) values in the range of 33.04 ± 4.3 to 131.68 ± 8.8 nM.