N,N'-Bridged 1,4,5,8-Tetrakis(methylamino)naphthalenes and Their Radical Cations. Comparison with 1,4,5,8-Tetrakis(dimethylamino)naphthalene and Related Radical Cations
作者:Thomas Barth、Franz A. Neugebauer
DOI:10.1021/jo00122a015
日期:1995.9
Syntheses of 3,8-dihydro-1,3,6,8-tetramethylpyrimido[4,5,6-gh]perimidine-2,7-(1H,6H)-dione (2), 1,2,3,6,7,8-hexahydro-1,3,6,8-tetramethylpyrimido[4,5,6-gh]perimidine (3), and 3,6,7,8-tetrahydro-1,3,6,8-tetramethylpyrimido[4,5,6-gh]perimidin-2(1H)-one (4) are reported. The corresponding radical cations were generated by oxidation with iodine or tris(4-bromophenyl)amminium hexachloroantimonate and were studied by ESR and ENDOR for comparison with the 1,4,5,8-tetrakis(dimethylamino)naphthalene radical cation (1(.+)), The ESR results of 2(.+)-4(.+), however, ave no indications which could explain the widely different exo (3.54 G) and endo (1.77 G) N-methyl proton splittings in 1(.+).