Unexpected regioselectivity in nitration of 3-aminoquinoxalin-2(1H)-ones

Regioselective nitration takes place at position 8 of 6,7-disubstituted-3-aminoquinoxalin-2(1H)-ones 3a-d. The orientation is not disturbed by the electronic or steric effects of the substituents on the aromatic ring and on the amino group. The isomeric 5-nitro derivative 9 is formed only in a round...

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Published inPerkin 1 : an international journal of organic and bio-organic chemistry no. 9; pp. 1417 - 1421
Main Authors Gönczi, C, Csikós, E, Podányi, B, Nusser, T, Böcskei, Z, Hermecz
Format Journal Article
LanguageEnglish
Published CAMBRIDGE Royal Soc Chemistry 01.01.2000
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
HETEROCYCLIC SYNTHESIS
SITE
POTENT
NUCLEAR MAGNETIC-RESONANCE
ANTAGONISTS
ETHYL CARBOETHOXYFORMIMIDATE
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Summary:Regioselective nitration takes place at position 8 of 6,7-disubstituted-3-aminoquinoxalin-2(1H)-ones 3a-d. The orientation is not disturbed by the electronic or steric effects of the substituents on the aromatic ring and on the amino group. The isomeric 5-nitro derivative 9 is formed only in a roundabout way from 3,6,7-trichloroquinoxalin-2(1H)-one 7. When position 8 is occupied, the 5- nitro derivatives appear only as a minor component. The isomers were identified by NMR techniques. Theoretical calculations (AM1, Hartree-Fock, B3LYP) and NMR investigations confirmed the presumed nitronium cation attack on the monoprotonated species 3ap.
ISSN:1472-7781
1470-4358
1364-5463
DOI:10.1039/a910234p