No abstract

[Reaction: see text]. 1,3-dinitrodibenz[b,f][1,4]oxazepin-11(10H)-one, prepared by intramolecular displacement of nitro group in N-(2-hydroxyphenyl)-2,4,6-trinitrobenzamide, reacts with O- and S-nucleophiles to yield the products of mono- or bis-substitution of the nitro groups. The nitro group in position 3 is displaced first. This observation is in contrast with earlier results for the nitro-substituted benzoannulated five-membered heterocycles. This difference in reactivity is likely due to the increased steric hindrance for peri-nitro group displacement in the case of the benzoannulated seven-membered heterocycle. N-Alkylation of the nitro-substituted dibenz[b,f][1,4]oxazepin-11(10H)-ones yields analogues of a known antidepressant drug Sintamil. The structure of the products is confirmed by NOE experiments and alternative synthesis.

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.

No abstract

Base catalyzed intramolecular nucleophilic substitution for the 2 nitro group in 2 hydr oxyanilides of 2 nitrobenzoic acids gave dibenzo[b,f ][1,4]oxazepin 11(10H ) ones. In particu lar, 3 nitrodibenzo[b,f ][1,4]oxazepin 11(10H ) one was obtained from N (2 hydroxyphenyl) 2,4 dinitrobenzamide. The nitro group in the product could also be replaced under the action of O and S nucleophiles.