38328-94-8Relevant academic research and scientific papers
Photochemical reactions of N-(2-halogenoalkanoyl) derivatives of anilines
Nishio, Takehiko,Asai, Hidenori,Miyazaki, Takenori
, p. 1475 - 1483 (2000)
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).
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).
