Aromatic Radical-Induced Aromatic 1,5-Hydrogen Transfer Of Benzene-naphthaline System With Nitrogen As The Bridge Atom

A series of diazonium salts of 4-(N-methyl-N-phenylamino)-3-amino-1,8-naphthalic anhydride 5a, its naphthalimide derivative 5b, and 5e were designed and synthesized,and it was the first time to discover that aromatic radical-induced intramolecular aromatic 1, 5-hydrogen transfer was also involved in the nitrogen-contianed system during Pschorr cyclization. In addition, the ratios of rearranged isomers increased from 9% (14a) to 14% (14b) and 16% (14e) as reducing the diffenrence of electron density between the two interacting aromatic system.In order to obtained the six-membered ring compound and a thorough assignment of the spectra, and further to prove that the six-membered ring compound was formed from the hydrogen transfer, the compound N-butyl-4-(N-methylphenylamino)-5-amino- 1, 8-naphthalimide 6 was designed to obtained with N-butyl-4-bromo-5-amino-1, 8-naphthalimide and N-methyl phenylamine as the starting material. However it was difficult to obtain the desired product as the different solvent giving the different products except the desired product. Subsequently, compound N-butyl-4-(N-methyl-2-nitrophenylamino)- 1, 8-naphthalimide 9 was designed to obtian from N-butyl-4-bromo-1, 8-naphthalimide and N-methyl 2-nitroaniline. Reaction conditions were screened including the changes of different solvents, the ratios of starting materials, the base and its amount, and the reaction temperature, however the desired product wasn't obtianed at all.UV-vis absorption and fluorescence spectrum of the compounds that prepared from the aromatic radical-induced intramolecular aromatic 1, 5-hydrogen transfer (including the five-membered and six-membered compounds) were recorded in various solvents. It was investigated that the substituent, the different bridge atom, and the different structure of the compounds have significant effect on UV-vis absorption and fluorescence spectrum.Compared to the compounds with oxygen or sulphur as the bridge atom, the compounds with nitrogen as the bridge atom, show red-shifted maximum absorption and emission wavelength were 64nm and 66nm. Especially the strength of the fluorescence was improved obviously, and the largest variable of fluorescence quantum yield was 0.6. the Stocks' shift didn't change much. The difference was formed for the electricity-donor of nitrogen was stronger then that of oxygen and sulphur. The absorption maxima and emission maxima didn't change obviously between the five-membered compounds when N-methyl as the bridge atom. The value of extinction coefficient was increased obviusly compared naphthalimide with naphthalic anhydride. The largest variable of logεwas 0.45, and the strength of the fluorescence was increased about 0.1.The polarity of the solvent greatly effected the uv-vis absorption spectrum, and the polarity increase, the absorption maxima showed red shift. However, the polarity of the solvent didn't effect the fluorescent strength obviously. The polarity of the solvent effeeted emission maxima the obviously.