Jbr. Devains et al., SYNTHESIS, THEORETICAL CONFORMATIONAL STUDY AND X-RAY STRUCTURES OF 2,2'-DIMETHYL-4,4'-BIPYRIMIDINE AND 6,6'-DIMETHYL-2,2'-BIPYRAZINE, New journal of chemistry, 18(6), 1994, pp. 701-708
The synthesis of 2,2'-dimethyl-4,4'-bipyrimidine (bpm) and 6,6'-dimeth
yl-2,2'-bipyrazine (bpz) is described. In these compounds the s-trans
molecular conformation has been observed and could be interpreted in t
erms of weak C-H...N interactions. The crystal stacking in the two com
pounds is formed by parallel molecular planes which are 3.46 angstrom
apart. A semi-empirical calculation shows that, irrespective of the me
dium, the molecules conserve this preferential conformation.