Ethyl 3-amino-2-cyano-4-(4-methoxyphenyl)-6- methylthieno[2,3-b]pyridine-5-carboxylate

In the title molecule, C19H17N3O3S, the bicyclic core is planar [maximum deviation = 0.0205 (1) Å] In the crystal, the molecules stack along thea-axis direction through π–π-stacking interactions between the bicyclic units with a small alternation in the interplanar distances along the stack. The stacks are held together by N—H...N and C—H...O hydrogen bonds. The carboethoxy substituent is disordered over several closely spaced sites and was modeled as having two-component disorder [occupancy ratio 0.548 (16):0.452 (16)]. The final refinement was as a two-component twin.

UNITS IN F2D2p

Let p be an odd prime, D2p be the dihedral group of order 2p, and F2 be the finite field with two elements. If * denotes the canonical involution of the group algebra F2D2p, then bicyclic units are unitary units. In this note, we investigate the structure of the group [Formula: see text], generated by the bicyclic units of the group algebra F2D2p. Further, we obtain the structure of the unit group [Formula: see text] and the unitary subgroup [Formula: see text], and we prove that both [Formula: see text] and [Formula: see text] are normal subgroups of [Formula: see text].

Bicyclic Units in some Integral Group Rings

A description is given of the unit group for the two groups G = D12 and G = D8 × C2. In particular, it is shown that in both cases the bicyclic units generate a torsion-free normal complement. It follows that the Bass-cyclic units together with the bicyclic units generate a subgroup of finite index in for all n ≥ 3.