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

Syntheses of thylpyrimido[4,5,6-gh]perimidine-2,7-(1H,6H)-dione (2), r o-1,3,6,8-tetramethylpyrimido[4,5,6-gh]perimidine (3), and 8-tetrameth ylpyrimido[4,5,6-gh]perimidin-2(1H)-one (4) are reported. The correspo nding radical cations were generated by oxidation with iodine or tris( 4-bromophenyl)amminium hexachloroantimonate and were studied by ESR an d ENDOR for comparison with the 1,4,5,8-tetrakis(dimethylamino)naphtha lene 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(.+).