1. Synthesis of Indolonesvia Radical Cyclization ofN-(2-Halogenoalkanoyl)-Substituted Anilines
- Author
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Takehiko Nishio, Kyoko Iseki, Takenori Miyazaki, and Norihito Araki
- Subjects
Inorganic Chemistry ,Chemistry ,Yield (chemistry) ,Organic Chemistry ,Drug Discovery ,Organic chemistry ,Physical and Theoretical Chemistry ,Biochemistry ,Medicinal chemistry ,Radical cyclization ,Catalysis - Abstract
The radical reactions of N-(2-halogenoalkanoyl)-substituted anilines (anilides) of type 1 have been investigated under various conditions. Treatment of compounds 1a–1o with Bu3SnH in the presence of (2,2′-azobis(isobutyronitrile) (AIBN) afforded a mixture of the indolones (oxindoles) 2a–2o and the reduction products 5a–5o (Table 1). In contrast, the N-unsubstituted anilides 1p–1s, 1u, and 1v gave the corresponding reduction products exclusively (Table 1). Similar results were obtained by treatment of 1 with Ni powder (Table 2) or wth Et3B (Table 3). Anilides with longer N-(phenylalkyl) chains such as 6 and 7 were inert towards radical cyclization, with the exception of N-benzyl-2-bromo-N,2-dimethylpropanamide (6b), which, upon treatment with Ni powder in i-PrOH, afforded the cyclized product 9b in low yield (Table 4). Upon irradiation, the extended anilides 6, 7, 10, and 11 yielded the corresponding dehydrobromination products exclusively (Table 5).
- Published
- 2005