FORMATION OF 4-(HET)ARYL-3<i>H</i>-1,5-BENZODIAZEPINE-2-CARBOXYLATES FROM (HET)AROYLPYRUVATE ESTERS AND <i>o</i>-PHENYLENEDIAMINE
DOI:
https://doi.org/10.1007/7252Keywords:
1, 5-benzodiazepines, 3-diketones, о-phenylenediamine, pyruvic acids, cyclocondensation.Abstract
Esters of (het)aroylpyruvic acids can react with о-phenylenediamine, leading to the formation of (Z)-3-(2-(het)aryl-2-oxoethylidene)-3,4dihydroquinoxalin-2(1H)-ones and 4-(het)aryl-3H-1,5-benzodiazepine-2-carboxylates. The obtained product ratio depends on the electronic effects due to substituents in the (het)aroyl moiety of (het)aroylpyruvate esters and the reaction conditions. The highest ratio of quinoxalinones relevant for medicinal chemistry was observed when using (het)aroylpyruvate esters without substituents that would cause a negative mesomeric effect in the (het)aroyl moiety, as well as when performing the reactions in acetic acid.