Facile synthesis of indole 3-acetic acid and azaindole 3-acetic acid derivatives

A practical and facile method for synthesizing indole 3-acetic acid and azaindole 3-acetic acid derivatives was developed by using 2-hydroxy-1-tosylindoline-3-triethylammonium bromide and 3-bromo-2-hydroxy-1-tosylazaindoline as starting materials. The lactone derivatives obtained by the reaction with Meldrum's acid and triethylamine were used as key intermediates, in which the acetic acid unit was introduced into the indole and azaindole skeleton. Twenty-six indole 3-acetic acid and azaindole 3-acetic acid derivatives were synthesized using these synthetic methods.