M. F. Budyka

Amination of 5-azacinnoline with aromatic amines

The 5-azacinnoline molecule was subjected to quantum-mechanical calculation by the Hückel method. The formation of 4-amino derivatives in the case of the reaction of 5-azacinnoline with aliphatic amines in the presence of an oxidizing agent and of 4,4′-bis(5-azacinnolinyl) in the case of dimerization in an oxygenfree medium was substantiated theoretically. The possibility of reactions with anions of aromatic amines was predicted by means of the Klopman method. It is shown that, in practice, the reaction is actually accelerated and that, in conformity with theory, the reaction center is the nitrogen atom of the aromatic amine. Possible products involving reaction with the participation of the pcarbon atom of the arylamine were not recorded. As in the case of aliphatic amines, the formation of a dimer was observed in an oxygen-free medium. The structures of the compounds obtained were proved by means of a combination of physicochemical methods.

New method for allowance for the activity of the nucleophile in calculations of the reactivities of heteroaromatic compounds

A new method for allowance for the activity of the nucleophile in calculations of the reactivities of heteroaromatic compounds that is based on the special application of the valence molecular orbital (VMO) theory in the form of Dewar reactivity numbers is proposed. It is shown that there is a correspondence between the proposed method and the general VMO theory. The 5-azacinnoline molecule was calculated by both methods. According to the calculations, the 6-C atom should be the most active in reactions with hard bases, whereas the 4-C atom should be the most active in reactions with soft bases. A qualitative correspondence between the proposed method and the DMTS (delocalization model of the transition state) method is also demonstrated in the case of the quinolinium cation.

Amination of 5-azacinnoline. instances of facile nucleophilic substitution of the hydrogen atom by an amino group

Direct nucleophilic substitution of the hydrogen atom by an amino group was observed in the case of 5-azacinnoline. The reaction with amines in the presence of an oxidizing agent under mild conditions leads to 4-amino-5-azacinnoline derivatives. Both electronic and steric factors affect the trend of the reaction. In the case of reactive amines the yields of the final products are close to quantitative. The formation of 4,4′-bis-5-azacinnolyl was observed in the absence of oxidizing agents. A probable scheme for the process that takes into account both possible reaction pathways is proposed. The structures of the products were proved by a combination of physicochemical methods and the results of elementary analysis.