Reaction of β-Lapachone with 1,2-Diamines: Facile Synthesis of Novel Tetracyclic Pyrazines

The reactions of beta-lapachone (1) with 1,2-diaminoethane (2) and 1,2-diaminopropane (4) gave the tetracyclic pyrazine derivatives (3) and mixtures of (5) and (6), respectively, while reaction with o-phenylene diamine (7) gave the quinoxaline derivative (8). The structure of pyrazine derivative (3) is confirmed by single-crystal X-ray diffraction study.