Nagarajan Vembu

Synthesis of mutual azo prodrugs of anti-inflammatory agents and peptides facilitated by α-aminoisobutyric acid.

Reported is the synthesis of azo mutual prodrugs of the nonsteroidal anti-inflammatory agents (NSAIDs) 4-aminophenylacetic acid (4-APAA) or 5-aminosalicylic acid (5-ASA) with peptides, including an antibiotic peptide temporin analogue modified at the amino terminal by an α-aminoisobutyric acid (Aib) residue. These prodrugs are designed for colonic delivery of two agents to treat infection and inflammation by the bacterial pathogen Clostridium difficile .

2‐Nitro­phenyl 4‐toluene­sulfonate: supramolecular aggregation through weak C—H⋯O, C—H⋯π and π–π interactions

In the crystal structure of the title compound, C17H14O3S, the dihedral angle between the mean planes of the 4-tolyl and 1-naphthyl rings is 45.05 (4)°. The supramolecular aggregation is completed by the presence of intermolecular C—H⋯O and C—H⋯π interactions.

N,N′-(Phenyl­imino­dimethyl­ene)di­prop-2-enamide hemihydrate

In the title compound, C14H17N3O2·0.5H2O, the asymmetric unit consists of an N,N′-(phenyliminodimethylene)diprop-2-enamide molecule and one half-molecule of water, with the O atom of the latter having 2 site symmetry. The supramolecular architecture is framed by the interplay of two-dimensional networks of both O—H⋯O and N—H⋯O interactions supported by C—H⋯O and edge-to-face C—H⋯π interactions.

2-Chlorophenyl 3-nitrobenzenesulfonate and 2,4-dichlorophenyl 3-nitrobenzenesulfonate: supramolecular aggregation through C-H...O, π-π and van der Waals interactions

In 2-chlorophenyl 3-nitrobenzenesulfonate, C(12)H(8)ClNO(5)S, and 2,4-dichlorophenyl 3-nitrobenzenesulfonate, C(12)H(7)Cl(2)NO(5)S, weak C-H...O interactions generate S(5), S(6) and R(2)(2)(7) rings. The supramolecular aggregation is completed by the presence of pi-pi interactions and intermolecular van der Waals short contacts.

Morpholinium 2,4,6-trinitro-phenolate.

There are two independent formula units in the asymmetric unit of the title compound, C4H10NO+·C6H2N3O7 −. The morpholinium cations in both molecules are puckered and adopt a chair conformation. Intermolecular N—H⋯O and C—H⋯O interactions generate rings of motifs R 2 1(5) and R 1 2(6). The supramolecular aggregation is completed by the presence of two co-operative hydrogen-bonded networks of further N—H⋯O interactions, which generate an infinite one-dimensional chain along the base vector [100]. Two C—H⋯π interactions are also seen.

Layer architecture in 4-nitrophenyl and 4-chlorophenyl 3-nitrobenzenesulfonate at 100 K.

The structures of the title compounds, C(12)H(8)N(2)O(7)S and C(12)H(8)ClNO(5)S, contain weak C-H.O interactions creating layers of molecules which, taking the conformation of the molecules into account, are arranged in an ABAB sequence. Both structures can be designated, therefore, as ordered racemates of rotameric species.

Benzene 1,3,5-tris(p-toluenesulfonate): Supramolecular aggregation through extensive C-H⋯O, C-H⋯π and π-π interactions

Within and between molecules of the title compound, C27H24O9S3, there are weak C—H⋯O interactions which generate rings of motifs S(5), S(6), R12(5), R22(14), R22(20), R12(6) and R21(4). The supramolecular aggregation is completed by the presence of C—H⋯π and π–π interactions.

Dimethyl 2,2'-[(4-oxo-2-phenyl-4H-chromene-5,7-di-yl)di-oxy]diacetate: a less densely packed polymorph.

The title molecule, C21H18O8, crystallizes in two crystal polymorphs, see also Nallasivam, Nethaji, Vembu & Jaswant [Acta Cryst. (2009), E65, o312–o313]. The main difference between the two polymorphs is in the conformation of the oxomethylacetate groups with regard to the almost planar [total puckering amplitude 0.047 (2) Å] chromene ring. In the title compound, the best planes of the oxomethylacetate groups through the non-H atoms are almost perpendicular to the chromene ring [making dihedral angles of 89.61 (6) and 80.59 (5)°], while in the second polymorph the molecules are close to planar. Both crystal structures are stabilized by C—H⋯O.

5,7-Dimeth­oxy-2-phenyl-4H-chromen-4-one

The asymmetric unit of the title compound, C17H14O4, contains two independent molecules which differ in the relative orientations of the phenyl rings with repect to the essentially planar [maximum deviations of 0.029 (2) and 0.050 (2) Å in the two molecules] chromene fused-ring system, forming dihedral angles of 10.3 (5) and 30.86 (5)° in the two molecules. The crystal structure is stabilized by weak C—H⋯O and C—-H⋯π interactions, and π–π stacking interactions.

4-Nitro­phenyl 4-bromo­benzene­sulfonate

In the title molecule, C12H8BrNO5S, the dihedral angle between the two benzene rings is 30.02 (7)°. The crystal structure is stabilized by weak C—H⋯O interactions.