Synthetic utilization of polynitroaromatic compounds. 6. Remarkable regioselectivity in nucleophilic displacement of aromatic nitro groups with amines.
5,7-Dinitroquinazoline-4-ones undergo nucleophilic displacement of a nitro group with N-, S-, and O-nucleophiles. In contrast to previously studied dinitro-substituted benzoannulated five- and seven-membered heterocycles (where a high degree of selectivity was observed), these quinazolines mostly yield mixtures of regioisomeric substitution products. At the same time, primary and secondary amines react selectively to afford 5-aminoquinazolones (peri-substitution). A similar effect is observed for some other polynitroaromatic compounds with adjacent nitro and carbonyl groups. This phenomenon is attributed to a stabilization of the intermediate peri-sigma-complex by intramolecular hydrogen bond N(+)-H...O double bond C.
Kislyi
Konstantine A
KA
N. D. Zelinsky Institute of Organic Chemistry RAS, Leninsky Pr., 47 Moscow, 119991, Russia.
Samet
Alexander V
AV
Strelenko
Yuri A
YA
Semenov
Victor V
VV