74492-45-8Relevant academic research and scientific papers
Synthesis of indolones via radical cyclization of N-(2-halogenoalkanoyl)- substituted anilines
Nishio, Takehiko,Iseki, Kyoko,Araki, Norihito,Miyazaki, Takenori
, p. 35 - 41 (2007/10/03)
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).
Photochemical reactions of N-(2-halogenoalkanoyl) derivatives of anilines
Nishio, Takehiko,Asai, Hidenori,Miyazaki, Takenori
, p. 1475 - 1483 (2007/10/03)
The photochemical reactions of 2-substituted N-(2-halogenoalkanoyl) derivatives 1 of anilines and 5 of cyclic amines are described. Under irradiation, 2-bromo-2-methylpropananilides 1a-e undergo exclusively dehydrobromination to give N-aryl-2-methylprop-2-enamides (= methacrylanilides) 3a-e (Scheme 1 and Table 1). On irradiation of N-alkyl- and N-phenyl-substituted 2-bromo-2-methylpropananilides 1f-m, cyclization products, i.e. 1,3-dihydro-2H-indol-2-ones (= oxindoles) 2f-m and 3,4- dihydroquinolin-2(1H)-ones (= dihydrocarbostyrils) 4f-m, are obtained, besides 3f-m. On the other hand, irradiation of N-methyl-substituted 2- chloro-2-phenylacetanilides 1o-q and 2-chloroacetanilide 1r gives oxindoles 2o-r as the sole product, but in low yields (Scheme 3 and Table 2). The photocyclization of the corresponding N-phenyl derivatives 1s-v to oxindoles 2s-v proceeds smoothly. A plausible mechanism for the formation of the photoproducts is proposed (Scheme 4). Irradiation of N-(2-halogenoalkanoyl) derivatives of cyclic amines 5a-c yields the cyclization products, i.e. five- membered lactams 6a, b, and/or dehydrohalogenation products 7a,c and their cyclization products 8a,c, depending on the ring size of the amines (Scheme 5 and Table 3).
