Synthesis of new chemosensors for fluoride ion from dehydroamino acid derivatives

摘要

The development of new anion sensors constitutes an important area of research. Fluoride is an important anion since it is a common ingredient in several drugs and also in water. The excess to fluoride exposure can cause severe damages to living organisms. Thus, detection of this anion using simple procedures is desirable [1]. In our laboratories we have developed a strategy for the synthesis of new bi-, tri- and tetracyclic heteroaromatic compounds from dehydroamino acid derivatives using a Suzuki-Miyaura coupling followed by a metal assisted intramolecular C-N cylization reaction [2]. Continuing this work and in order to prepare new chemosensors, we have decided to apply our strategy to the synthesis of a methyl 3-(phenanthren-9-yl)-1H-dibenzo[e,g]indole-2-carboxylate 4 and a methyl 1-(naphthalen-l-yl)-3H-benzo[e]indole-2-carboxylate 5 (Scheme 1). The Suzuki coupling afforded the β,β-disubstituted dehydroamino acids, 2 and 3 which were submitted to our cyclization conditions giving compounds 4 and 5 in 30 % and 86 % yield.