Amide Ion Formation and N-Alkylation of Aminoanthraquinones in the presence of Potassium Hydroxide in Dimethyl Sulfoxide

Article abstract of DOI:10.1246/bcsj.58.1458

Amide ions were formed by the deprotonation of the amino group of amino group of amino- and (monoalkylamino)anthroquinones in the presence of powdered potassium hydroxide in dimethyl sulfoxide (DMSO).Under a nitrogen atmosphere these amide ions changed to their radical anions.The amide ions of 1-aminoanthroquinones reacted with excess alkyl halides to yield 1-alkylaminoanthraquinones, while the N-alkylation of 2-aminoanthraquinones afforded 2-alkylaminoanthraquinones in good yields. 2-Aminobenzophenone underwent mono-N-alkylation, while 4-aminoazobenzene and p-nitroaniline underwent di-N-alkylation.It was also found that carbanion of DMSO easily attacked the carbonyl group of the (dialkylamino)anthraquinones.