The synthesis of azaisomers of the triester of PQQ: 3H-pyrrolo[3,2-f]-, 1H-pyrrolo[3,2-h]-, and 7H-pyrrolo[2,3-h]quinolinequinone derivatives

Article abstract of DOI:10.1002/hlca.19940770114

We describe here the synthesis of the title compounds 3-5, starting from highly substituted aminoindoles. The annelated pyridine rings were built up in each case with dimethyl 4-oxoglutaconate according to Corey's procedure. All three o-quinone derivatives 3-5 are stable compounds, comparable to PQQ-triester. The azaisomers vary in biological activity from practically inactive to strong inhibition of the α-amidating enzyme or the ornithin decarboxylase.