キノンとエナミンとの反応に基づいたヘテロ環縮合キノン類のワンポット合成

抄録

New simple methods for the preparation of heterocycle-fused quinone derivatives based on tandem Michael addition-cyclization sequence between quinones and enamines (or imines) have been developed. The reaction of 2-hydroxy-1, 4-naphthoquinones with enamines, derived from ketones, afforded 2, 3-disubstituted naphtho [2, 3-b] furan-4, 9-diones. 1H-Benz [f] indole-4, 9-diones could be prepared by treating 2-trifluoroacetylamino-1, 4-naphthoquinone with enamines. The similar pyrrole ring formation took place by using a 2-trifluoroacetylamino-1, 4-benzoquinone to give 1H-indole-4, 7-diones. 2, 3-Disubstituted naphtho [2, 3-b] thiophene-4, 9-diones were synthesized from 2- [2- (ethoxycarbonyl) ethylthio] -1, 4-naphthoquinone and enamines. 1H-Naphtho [2, 3-c] pyran-5, 10-dione derivatives, including a natural product (pentalongin), were prepared from 2- (1-hydroxyalkyl) -1, 4-naphthoquinones and enamines (or imines). The utility of this method was demonstrated in the synthesis of pyranonaphthoquinone antibiotics, (±) -eleutherin and (±) -isoeleutherin. 1H-2-Benzopyran-5, 8-dione derivatives were similarly synthesized from 2-alkoxy-6- (1-hydroxyalkyl) -1, 4-benzoquinones. Treatment of 2-acyl-1, 4-naphthoquinones or 2-acyl-5, 6-dimethyl-1, 4-benzoquinones with enamines (or imines), followed by addition of aqueous ammonia, afforded benz [g] isoquinoline-5, 10-diones or isoquinoline-5, 8-diones, respectively.