Reaction of nitrile oxides with N-aryl-S,S-dimethylsulfimides.

概要

論文の詳細を見る
Both benzimidazole 3-oxides and 1,2,4-benzoxadiazines were formed in reactions of sterically-stabilized benzonitrile oxides with N-aryl-S,S-dimethylsulfimides, whereas only 1,2,4-benzoxadiazines were produced in reactions of 2,6-unsubstituted benzonitrile oxides. The reactions are thought to proceed via the intermediacy of a nitroso compound formed by the nucleophilic attack of sulfimide on the carbon atom of the nitrile oxide and the subsequent release of dimethyl sulfide. The nitrogen or the oxygen atom of the nitroso group of this intermediate can attack the ortho position of the benzene ring originating from sulfimide to form benzimidazole 3-oxide or 1,2,4-benzoxadiazine, respectively, Conjugation of the nitroso group with the C-aryl group can be attained in s-cis form for the intermediate derived from 2,6-unsubstituted benzonitrile oxide, and thus, exclusive O-attack takes place to afford 1,2,4-benzoxadiazines. On the other hand, conjugation of the nitroso group with the C-aryl group cannot be considered for the intermediate derived from 2,6-disubstituted benzonitrile oxide because of the steric hindrance of the substituents. In this case, the intermediate nitroso compound is either in s-cis or in s-trans form. This causes the formation of both benzimidazole 3-oxide and 1,2,4-benzoxadiazine. Characterization data of benzimidazole 3-oxides are also described.
公益社団法人日本化学会の論文