1,2-Ethylene-bis(p-N²-phenylene-N¹,N¹-dimethylformamidine)

A mixture of 4.28 mmol (1.1328 g) bibenzil-4,4-di-yl-diisocyanate (1) [1] and 84 mmol (6.14 g) of redistilled N,N-dimethylformamide (2) was refluxed under stirring using a magnetically stirring-bar for 12 h, with complete absorption for any carbon dioxide in aqueous potassium hydroxide solution [2]. The major portion of the unchanged 2 was removed by vacuum distillation. After cooling the residue is triturated with diethyl ether. The precipitated solid is recrystallized from ethanol to afford 1.22 g (90 %) of 3.

M.p. : 182 - 183°C.

IR (cm^-1): 1640; 1610 (C=N); 1510; 1500; 1370 (C-N); 840.

¹H NMR (CDCl3): 7.5 (s, 2H, -CH=N); 6.95 (d, 4H, HAr, ortho to N=); 6.90 (d, 4H, HAr, ortho to -CH2-CH2-); 3.08 (s, 12 H, -CH3); 2.88 (s, 4H, >CH2).

Anal. calc. For C20H26N4 (322.457): C 74.50, H 8.13, N 17.37; Found: C 74.40, H 8.12, N 17.48.