Reactive 2-quinolones dearomatized by steric repulsion between 1-methyl and 8-substituted groups
摘要:
Usual 1-methyl-2-quinolone (MeQone) derivatives are not reactive because of aromatic property in the heterocyclic ring. On the other hand, 8-substituted MeQones have been proved to be highly reactive, which is caused by steric repulsion between the 1-methyl and the 8-substituted groups. When 1-methyl-3,6,8-trinitro-2-quinolone was treated with potassium (or trimethylsilyl) cyanide, cyanation proceeded at the 4-position regioselectively as a result of cine-substitution. This reaction is initiated with addition of cyanide species, and the cyanoquinolone is formed by the protonation of the resultant anionic intermediate followed by elimination of nitrous acid. The high reactivity was maintained even when one of the nitro groups on the benzene moiety was replaced by a methyl group, which afforded corresponding cine-substituted products upon treatment with potassium cyanide. (C) 2013 Elsevier Ltd. All rights reserved.
Reactive 2-quinolones dearomatized by steric repulsion between 1-methyl and 8-substituted groups
摘要:
Usual 1-methyl-2-quinolone (MeQone) derivatives are not reactive because of aromatic property in the heterocyclic ring. On the other hand, 8-substituted MeQones have been proved to be highly reactive, which is caused by steric repulsion between the 1-methyl and the 8-substituted groups. When 1-methyl-3,6,8-trinitro-2-quinolone was treated with potassium (or trimethylsilyl) cyanide, cyanation proceeded at the 4-position regioselectively as a result of cine-substitution. This reaction is initiated with addition of cyanide species, and the cyanoquinolone is formed by the protonation of the resultant anionic intermediate followed by elimination of nitrous acid. The high reactivity was maintained even when one of the nitro groups on the benzene moiety was replaced by a methyl group, which afforded corresponding cine-substituted products upon treatment with potassium cyanide. (C) 2013 Elsevier Ltd. All rights reserved.
Direct amino-halogenation and aziridination of the 2-quinolone framework by sequential treatment of 3-nitro-2-quinolone with amine and N-halosuccinimide
sequential treatment of 3-nitro-2-quinolones with amines and N-halosuccinimides under mild conditions facilitated the direct amino-halogenation and aziridination at the 4- and 3-positions of the 2-quinolone framework. The selectivity of the functionalization was influenced by the electronic properties of the substituents on the benzene moiety of the nitroquinolone. The electron-withdrawing nitro group
Bis(functionalization), 4-alkoxylation and 3-chlorination, of the 1-methyl-2-quinolone framework was achieved by a sequential treatment of 3-nitrated 2-quinolones with sodium alkoxide and NCS.
Usual 1-methyl-2-quinolone (MeQone) derivatives are not reactive because of aromatic property in the heterocyclic ring. On the other hand, 8-substituted MeQones have been proved to be highly reactive, which is caused by steric repulsion between the 1-methyl and the 8-substituted groups. When 1-methyl-3,6,8-trinitro-2-quinolone was treated with potassium (or trimethylsilyl) cyanide, cyanation proceeded at the 4-position regioselectively as a result of cine-substitution. This reaction is initiated with addition of cyanide species, and the cyanoquinolone is formed by the protonation of the resultant anionic intermediate followed by elimination of nitrous acid. The high reactivity was maintained even when one of the nitro groups on the benzene moiety was replaced by a methyl group, which afforded corresponding cine-substituted products upon treatment with potassium cyanide. (C) 2013 Elsevier Ltd. All rights reserved.