The reactions of 2-halogenonaphthoquinones (5, 13, 14 and 15) and 2-methyl-1, 4-naphthoquinone (20; vitamin K3) with primary and secondary amines were examined. 1, 3-Dialkyl-1, 2, 3, 4-tetrahydrobenzo[g]quinazoline-5, 10-diones (9) were obtained in moderate yields by treating 20 with formaldehyde in primary amines. A plausible reaction path-way is also presented.
2-Methylamino-3-(1-piperidinylmethyl)-1, 4-naphthoquinone (7) was prepared via several steps from 2-methyl-1, 4-naphthoquinone (vitamin K3, 3). The quinone (7) was photochemically oxidized to 2-methylamino-3-(1-piperidinylcarbonyl)-1, 4-naphthoquinone (8) and/or 2-alkoxycarbonyl-3-methylamino-1, 4-naphthoquinone (9), depending on the solvent used.