Carboxamide–pyridine N-oxide heterosynthon for crystal engineering and pharmaceutical cocrystals

Abstract

The novel carboxamide-pyridine N-oxide synthon, sustained via N-H...O- hydrogen bonding and C-H...O interaction, is shown to assemble isonicotinamide N-oxide in a triple helix architecture and the same heterosynthon is exploited to synthesize cocrystals of barbiturate drugs with 4,4'-bipyridine N,N'-dioxide.

Halogen-Bonded Co-Crystals of Aromatic N-oxides: Polydentate Acceptors for Halogen and Hydrogen Bonds

“…The C−H···O contacts are attractive, and are rather site acidity-dependent. For example, the C2-proton acidity in pyridine N-oxides for ortho-C−H functionalization in organic synthesis [19][20][21][22][23][24][25], and in crystal engineering for C−H···O−N interactions is well studied [51][52][53][54]. However, to the best of our knowledge, the combination of C−H···O−N and C−I···O−N interactions through the N−O group, giving rise to supramolecular assemblies, has not been extensively studied.…”

Benefits of cocrystallisation in pharmaceutical materials science: an update

“…In the context of pharmaceutical materials, hydrogen‐bonded synthons have been principally investigated to date, although a potential role for halogen bonds is suggested by the recent discovery of such interactions in biomolecular recognition [14] . The number of supramolecular synthons that are regularly used in crystal engineering and cocrystallisation is relatively small and is probably less than ten [15] . Cocrystal formation can be recognised as a natural choice to construct new solid forms of APIs when it is realised that the functional groups that are most important in cocrystal design are also frequent in pharmaceutically active molecules.…”

Aromatic N-oxide bridged copper(II) coordination polymers: Synthesis, characterization and magnetic properties

“…Moreover, researchers have reported several aromatic N-oxide derivatives capable of forming biologically active metal complexes [7,8]. Apart from these, coordination complexes of aromatic N-oxides are known to have extensive applications as magnetic materials [7,[9][10][11][12], in catalysis [13][14][15][16][17][18][19] as well as in supramolecular systems [20][21][22][23][24][25][26][27][28][29][30][31].…”