K. Rajesh

Ultrasound-promoted synthesis of bi-, tri- and tetrapodal polyhydroquinolines, 1,4-dihydropyridines and the corresponding pyridines

Bi-, tri- and tetrapodal polyhydroquinolines and 1,4-dihydropyridines were synthesised by the reaction of various alkylating agents with polyhydroquinolines and 1,4-dihydropyridines under sonication conditions. These were in turn converted to the corresponding pyridines also using sonication. Sonication produced higher yields in a faster reaction time. All the synthesized compounds were characterized using spectral data.

1,1'-(p-Phenyl-enedimethyl-ene)dipiperidin-4-one.

In the molecule of the title compound, C18H24N2O2, the piperidine rings are in chair conformations. The crystal structure is stabilized by intermolecular C—H⋯O hydrogen bonding. There are neither C—H⋯π nor π–π interactions in the structure.

9-(4-Hy-droxy-phen-yl)-3,3,6,6-tetra-methyl-4,5,6,9-tetra-hydro-3H-xanthene-1,8(2H,7H)-dione.

In the title compound, C23H26O4, the two cyclohexene rings adopt envelope conformations whereas the pyran ring adopts a boat conformation. In the crystal, pairs of intermolecular O—H⋯O hydrogen bonds link the molecules into inversion dimers.

4-Azido-2-chloro-6-methyl­quinoline

In the title compound, C10H7ClN4, the quinoline ring system is planar [maximum deviation 0.0035 (10) Å]. The crystal structure is stabilized by van der Waals and π–π stacking interactions [centroid–centroid distance 3.6456 (17) Å].

Synthesis of novel 9-((arylidene)hydrazono)-2,4,6,8-tetrakis(4-methoxyphenyl)-3,7-diazabicyclo[3.3.1]nonane azines as potential antibacterial agents

Some novel 9-((arylidene)hydrazono)-2,4,6,8-tetrakis(4-methoxyphenyl)-3,7-diazabicyclo[3.3.1]nonane azines were synthesized, and characterized by use of spectral data. Their antibacterial activity against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus was evaluated.

Regioselective synthesis of novel 2-chloroquinoline derivatives of 1,4-dihydropyridines

Highly regioselective reaction of some substituted 2,4-dichloroquinolines with symmetrical 1,4-dihydropyridines, leading to novel quinoline derivatives of DHPs, has been achieved in the presence of powdered K2CO3, as a mild and efficient base, at moderate temperature. All the synthesized compounds were characterized by use of IR, NMR, and mass spectral data.

1-[2,4,6-Trimethyl-3,5-bis­(4-oxopiperidin-1-ylmeth­yl)benz­yl]piperidin-4-one

In the structure of the title compound, C27H39N3O3, each of the (4-oxopiperidin-1-yl)methyl residues adopts a flattened chair conformation (with the N and carbonyl groups being oriented to either side of the central C4 plane) and they occupy positions approximately orthogonal to the central benzene ring [Cbenzene—C—Cmethylene—N torsion angles 103.4 (2), −104.4 (3) and 71.9 (3)°]; further, two of these residues are oriented to one side of the central benzene ring with the third to the other side. In the crystal packing, supramolecular layers in the ab plane are sustained by C—H⋯O interactions.

1-{3-[(4-Oxopiperidin-1-yl)carbon­yl]benzoyl}piperidin-4-one

Two independent molecules comprise the asymmetric unit in the title compound, C18H20N2O4. One of the molecules exhibits disorder in one of its 4-piperidone rings, which is disposed over two orientations [site occupancy of the major component = 0.651 (5)]. The first independent molecule and the minor component of the second disordered molecule are virtually superimposable. The central four C atoms in the major component of the disordered molecule have an opposite orientation. All the 4-piperidone rings have a chair conformation. The carbonyl groups in each molecule have approximate anti conformations [O=C⋯C=O = 146.2 (2) and −159.9 (2)°]. The 4-piperidone rings lie to opposite sides of the central benzene ring in both molecules. In the crystal, molecules are linked by C—H⋯O interactions. The crystal studied was found to be a non-merohedral twin (twin law −1 0 0, 0 1 0, 0 − 1/2 − 1), the fractional contribution of the minor component being approximately 11%.

Dimethyl 4-(3-hydroxy-phen-yl)-2,6-dimethyl-1,4-dihydro-pyridine-3,5-dicarboxyl-ate.

The 1,4-dihydropyridine ring in the title compound, C17H19NO5, has a flattened-boat conformation, and the benzene ring is almost orthogonal to it [dihedral angle = 82.98 (12)°]. The hydroxy group is disordered over two positions in a 0.780 (4):0.220 (4) ratio. In the crystal, hydrogen-bonding interactions of the type Na—H⋯Oc and Oh—H⋯Oc (a = amine, c = carbonyl and h = hydroxy) link the molecules into a three-dimensional network.

2,4,6,8-Tetra­kis(2-methoxy­phen­yl)-3,7-diaza­bicyclo­[3.3.1]nonan-9-one diethyl ether hemisolvate

In the title compound, C35H36N2O5·0.5C4H10O, the asymmetric unit contains one bicyclo[3.3.1]nonane molecule and a half-occupancy diethyl ether solvent with the O atom lying on a crystallographic inversion center. Two intramolecular N—H⋯O hydrogen bonds generate S(6) ring motifs. The bicyclo[3.3.1]nonane ring system adopts a chair-boat conformation. In the crystal structure, the molecules are linked by weak intermolecular C—H⋯N hydrogen bonds into chains along the b axis; additional stabilization is provide by C—H⋯π interactions.