Direct Amination of 9-Hydroxy-1-oxophenalene to Produce 9-Amino-1-oxophenalene and Related Compounds

Abstract

In connection with our studies of organo-non-metallic complexes of the 1,9-disubstituted phenalene unit 1 we required access to compounds possessing a total of just two ionizable hydrogen atoms in the A,B groups of 1. The prototypical compound in this series, 9-amino-1-oxophenalene (2), is not known although 9-hydroxy-l-oxophenalene (3) was first prepared in 1941 and a number of derivatives of 1 possessing one or three ionizable hydrogen atoms in the A,B groups have recently become available. We have found that the high-pressure reaction between 9-hydroxy-1-oxophenalene (3) and aqueous ammonia affords the desired 9-amino-1-oxophenalene (2) in high yield and good purity under relatively mild conditions. In addition 2 may be alkylated to produce the 9-amino-l-ethoxyphenalenylium salt which serves as a precursor for the other derivatives in this series with two ionizable hydrogen atoms in the A,B groups of 1.