A disordered ring in the molecular structure of cyclopentanecarboxamide (CYCLAM)

Cyclohexanecarboxamide

“…The presence of a C-HÁ Á ÁO interaction to stabilize the R 4 6 (16) network does, however, seem to be required. In addition, the title compound is isomorphous with a previously published structure of cyclopentanecarboxamide [Winter et al (1981). Acta Cryst.…”

“…The combination of the two hydrogen bonds also results in a motif that can be described by the secondary graph set R 4 6 (16). A search of the Cambridge Structural Database (CSD; Version 5.30, November 2008 release; Allen, 2002) led to the discovery of the isomorphous structure of cyclopentanecarboxamide (CSD refcode BARFEF; Winter et al, 1981), which has an identical hydrogen-bonding pattern despite the presence of disorder in the five-membered ring. The R 4 6 (16) motif can also be found in the structures of 1-phenylcyclopentanecarboxamide and 1-(2-bromophenyl)cyclohexanecarboxamide, indicating that replacing atom H2 with a more bulky group does not necessarily disrupt this hydrogen-bond pattern (Lemmerer & Michael, 2008).…”

Hydrogen bonding patterns in a series of 1-arylcycloalkanecarboxamides

“…3b), with the hydrogen-bonded ring forming the crossbar. This shape sterically prevents neighbouring dimers from approaching each other and engaging in additional interactions 19 This compound possesses the same hydrogen bonding pattern as 1; and although the cyclopentane ring adopts a disordered envelope conformation, the amide substituent is effectively equatorial. Table 3 Summary of packing and hydrogen bonding in compounds 1-5 Graph set notation 8)…”