Synthesis of a second generation chroman/catechol hybrids and evaluation of their activity in protecting neuronal cells from oxidative stress-induced cell death.

A new generation of chroman/catechol hybrids bearing heterocyclic five-membered rings, such as 1,2,4-oxadiazole 1,3,4-oxadiazole, 1,2,3-triazole, tetrazole and isoxazole, were designed and synthesized. The activity of the new derivatives against oxidative stress induced neuronal damage, was evaluated using glutamate-challenged hippocampal HT22 cells. Compound 3 in which a 3,4-dimethoxyphenyl moiety, is directly attached to the 1,2,4-oxadiazole ring was the most active among the 2-substituted chroman analogues, with EC(50)=254+/-65nM. Concerning the 5-subtituted chroman analogues, isoxazole derivative 29 exhibited the strongest activity (EC(50)=245+/-38nM). However, 29 was cytotoxic at concentrations higher than 1microM, while the triazole analogue 24 (EC(50)=801+/-229nM), was non-toxic at all concentrations tested.