Simple, fast and efficient synthesis of ß-keto esters from the esters of heteroaryl compounds, its antimicrobial study and cytotoxicity towards various cancer cell lines.

A series of ß-keto esters were synthesized from heteroaryl esters and ethyl acetate using LiHMDS as base at -50 to -30 °C. The increase in yields of cross condensed product were observed and the percentage of self condensed product was reduced drastically by applying the suitable base (LiHMDS), solvent and the minimum amount of ethyl acetate. All these ß-keto esters were characterized using (1)H NMR, (13)C NMR and mass spectral data. A plausible mechanism is also depicted to prove the formation of trans-esterified products. All the synthesized compounds were subjected to test for their cytotoxicity towards various cancer cell lines and also tested for their antimicrobial activity towards various bacterial and fungal strains and some of them were found to have promising activity.

3-Hy-droxy-2-[(2-hy-droxy-4,4-dimethyl-6-oxocyclo-hex-1-en-1-yl)(3-nitro-phen-yl)meth-yl]-5,5-dimethyl-cyclo-hex-2-en-1-one.

Each of the cyclohexenone rings in the title compound, C(23)H(27)NO(6), adopts a half-chair (envelope) conformation with the C atom carrying the methyl groups lying out of the plane defined by the five remaining C atoms; the O atoms lie to the same side of the mol-ecule as the respective >C(CH(3))(2) atoms. The hy-droxy and carbonyl O atoms face each other and are orientated to allow for the formation of two intra-molecular O-H⋯O hydrogen bonds. In the crystal, the presence of C-H⋯O contacts leads to the formation of supra-molecular chains along the b axis. These aggregate into layers that stack along c.

Hantzsch 1,4-dihydropyridine esters and analogs: candidates for generating reproducible one-dimensional packing motifs.

Examination of the symmetric Hantzsch 1,4-dihydropyridine ester derivatives of the prototypical nifedipine molecule indicates the tendency of this class of molecule to form a common packing motif. Crystal structure analysis of 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylic diesters and analogs reveals that they form extended chains, characterized as the C(6) packing motif, via intermolecular (amine) N-H...O=C (C3,C5 carbonyl) hydrogen bonds. In addition, all the prepared derivatives also satisfy the basic structural requirements for their high binding efficiency to the receptor. The reproducible C(6) packing motif observed among these compounds has a use in the design of solid-state materials.

Ultrasound-promoted synthesis of novel bipodal and tripodalpiperidin-4-ones and silica chloride mediated conversion to its piperidin-4-ols: synthesis and structural confinements.

The ultrasound-promoted synthesis of novel bipodal and tripodalpiperidin-4-ones was carried out by the reaction of 4-piperidone hydrochloride monohydrate with different alkylating and acylating agents. It was preferably reduced to respective piperidin-4-ols by ultrasonic irradiation using silica chloride, which maintains higher yields by acting as an effective supporting polymer. The sterically hindered phthaloyl derivative of piperidin-4-one was synthesized by ultrasonic irradiation which was difficult by conventional methods.