2-(4-Bromo­phen­yl)-N-(pyrazin-2-yl)acetamide

In the title compound, C₁₂H₁₀BrN₃O, the dihedral angle between the mean planes of the 4-bromo­phenyl and pyrazin-2-yl rings is 54.6 (3)°. An intra­molecular C—H...O hydrogen bond generates an S(6) graph-set motif. In the crystal, weak N—H...N hydrogen bonds link the mol­ecules into chains along [100]. The chains are linked via C—H...N and C—H...O hydrogen bonds, forming two-dimensional networks lying parallel to the ab plane.

2-(4-Bromo­phen­yl)-N-(3,4-di­fluoro­phen­yl)acetamide

In the title compound, C₁₄H₁₀BrF₂NO, the dihedral angle between the mean planes of the 4-bromo­phenyl and 3,4-di­fluoro­phenyl rings is 66.4 (1)°. These two planes are twisted by 40.0 (5) and 86.3 (2)°, respectively, from that of the acetamide group. In the crystal, N—H...O hydrogen bonds and weak C—H...O and C—H...F inter­actions form infinite chains along [100].

Rupatadine

In the title compound (systematic name: 8-chloro-11-{1-[(5-methyl­pyridin-3-yl)meth­yl]piperidin-4-yl­idene}-6,11-di­hydro-5H-benzo[5,6]cyclo­hepta­[1,2-b]pyridine), C₂₆H₂₆ClN₃, the dihedral angle between the mean planes of the chloro­phenyl and cyclo­hepta­[1,2-b]pyridinyl rings fused to the cyclo­heptane ring is 56.6 (1)°. The mean planes of the cyclo­hepta­[1,2-b]pyridinyl and 5-methyl­pyridin-3-yl rings are twisted by 64.9 (4)°. The central piperizene group is in a slightly distorted chair configuration. A weak intra­molecular C—H...N inter­action is observed between the cyclo­hepta­[1,2-b]pyridinyl and piperidin-4-yl­idene moieties.

2-(4-Chloro­phen­yl)-N-(3,4-di­fluoro­phen­yl)acetamide

In the title compound, C₁₄H₁₀ClF₂NO, the dihedral angle between the mean planes of the 4-chloro­phenyl and 3,4-di­fluoro­phenyl rings is 65.2 (1)°. These two planes are twisted by 83.5 (5) and 38.9 (9)°, respectively, from that of the acetamide group. In the crystal, N—H...O hydrogen bonds form infinite chains along [100]. Weak C—H...O and C—H...F inter­actions are also observed and stack mol­ecules along the b axis.