含窒素共軛系ジエンに関するDiels-Alder反応 (第3報)

Abstract

There has been no example of a Diels-Alder type reaction taking place in conjugated diene system containing anil nitrogen and the present series of experiments were carried out in order to examine the behavior of such compounds, especially N=C-C=N type dianils, in such a reaction. Reaction of the known, glyoxal bis-(4-dimethylaminoanil) with maleic anhydride was first carried out. While this substance itself is stable when alone, it was found to undergo hydrolysis with a minute amount of water in the solvent, in the presence of maleic anhydride, resulting in the severance of anil bonding. It was thereby learned that p-dimethylaminoaniline thereby formed reacted with maleic anhydride to form maleic acid mono-p-dimethylaminoanilide, and that the minute amount of free maleic acid present in the anhydride acted catalytically. Reaction of the same starting material with p-quinone did not materialize at the reflux temperature of benzene or xylene, but on heating a benzene solution of the two in a sealed tube at 160-170°, a crystalline compound, whose analytical values agreed with those for an equimolar adduct of the two, was obtained. From its infrared absorption spectrum, the adduct was thought to be a product of the anticipated reaction.