Hari N. Pati

Alkylation of Ethanolamines: An Approach to a Novel Class of Functional Surfactants

Abstract Some monomeric and dimeric surfactants with functional head groups have been synthesized from di- and triethanolamine synthons. The treatment of alkyl bromide with triethanolamine resulted in simultaneous N-alkylation and O-alkylation products. However, with diethanolamine, N-alkylated products were obtained, which were further used to synthesize various double-tailed surfactants and gemini surfactants.

Separation, Isolation, and Characterization of Isoform Impurities of Gemcitabine Formed During the Anomerization of Protected α‐Gemcitabine to Gemcitabine

Abstract In the impurity profile of the gemcitabine active pharmaceutical ingredient, two process related impurities (0.12%) were detected other than the known α‐isomer of gemcitabine impurity in HPLC with respect to gemcitabine. The mass spectral data and UV spectrum of these two impurities were similar to that of gemcitabine. These impurities were referred as isoform impurity I and isoform impurity II. These isoform impurities were isolated from a crude sample of gemcitabine bulk drug using a reverse phase preparative high performance liquid chromatography (prep‐HPLC), and were characterized by LC‐MS, LC‐MS/MS, and FT‐NMR experimental techniques. Based on the results obtained from the different spectroscopic experiments, these isoform impurities were characterized as β‐anomer of 4‐amino‐1‐(3,3‐difluoro‐4,5‐dihydroxy tetrahydro‐2H‐pyran‐2‐yl)pyrimidin‐2(1H)‐one (isoform impurity I) and α‐anomer of 4‐amino‐1‐(3,3‐difluoro‐4,5‐dihydroxy tetrahydro‐2H‐pyran‐2‐yl)pyrimidin‐2(1H)‐one (isoform impurity II), respectively. Formation, separation, isolation, and characterization of these isoform impurities were discussed in detail.

Design, Synthesis, and Cytotoxicity of Novel 3‐Arylidenones Derived from Alicyclic Ketones

Forty‐four novel chalcone‐inspired analogs having a 3‐aryl‐2‐propenoyl moiety derived from alicyclic ketones were designed, synthesized, and investigated for cytotoxicity against murine B16 and L1210 cancer cell lines. The analogs belong to four structurally divergent series, three of which (series g, h, and i) contain differently substituted cyclopentanone units and the fourth (series j) contains a 3,3‐dimethyl‐4‐piperidinone moiety. Of these, the analogs in series j showed potential cytotoxic activity against murine B16 (melanoma) and L1210 (lymphoma) cells. The most active compounds 5j, 11j, 15j, and 12h produced IC50 values from 4.4 to 15u2003μm against both cell lines. A single‐crystal X‐ray structure analysis and molecular modeling studies confirmed that these chalcones have an E‐geometry about the alkene bond and possess a slightly ‘twisted’ conformation similar to that of combretastatin A‐4. At a concentration of 30u2003μm, compounds 5j, 11j, and 15j did not cause microtubule depolymerization in cells, suggesting that they have a different mechanism of action.

5-Benzyl-idene-3-phenyl-2-phenyl-imino-1,3-thia-zolidin-4-one.

The title compound, C22H16N2OS, is a chalcone analog with a thiazolidinone core that was synthesized as a potential cytotoxic and anticancer agent. The structure is commensurately modulated by unit-cell doubling along the direction of the a axis of the cell. The two crystallographically independent molecules are differerentiated by the dihedral angle between the mean planes of the benzylidene phenyl group against the thiazolidin-4-one moiety, which is 5.01u2005(7)° in one molecule, and 17.41u2005(6)° in the other. The two molecules are otherwise close to being indistinguishable and are related by crystallographic pseudo-translation. The two molecules are not planar but are slightly bent with the benzylidene and phenylimino substituents being bent upwards with respect to the center planes of the two molecules. The degree of bending of the two halves of the thiazolidin-4-one moieties (defined as the planes that intersect at the S atom) are 11.08u2005(7) and 15.88u2005(7)°. Packing of the molecules is facilitated by C—H⋯π interactions and slipped π–π stacking between one of the phenyl rings and a neighboring ethylene π system [distance between the centroid of the ethylene group and the closest phenyl C atom = 3.267u2005(2)u2005Å, Cg(phenyl)⋯Cg(ethylene) = 3.926u2005Å].

Synthesis of 2-[4-(4-Chlorophenyl)piperazin-1-yl]-2-methylpropanoic Acid Ethyl Ester

The title compound was synthesized by N-alkylation of 4-(4-chlorophenyl)piperazine with ethyl 2-bromo-2-methylpropanoate and its IR, 1H NMR, 13C NMR and Mass spectroscopic data are reported.

1-(3-methoxyphenyl)-2-phenylethanone oxime

In the structure of the title compound, C15H15NO2, the dihedral angle between the two benzene rings is 86.8u2005(1)°. An intraxadmolecular methylxadene–oxime C—H⋯O hydrogen bond stabilizes the molxadecular structure. Interxadmolecular O—H⋯N hydrogen bonds between oxime subxadunits cluster the molxadecules into R22(6) dimers. Aromatic–aromatic stacking interxadactions are also observed in the packing [interxadplanar distance 3.344u2005A, slippage 4.107u2005A, centroid-to-centroid distance 5.297u2005(2)u2005A] and these, combined with the O—H⋯N hydrogen bonds, form a one-dimensional array of molxadecules along the b axis.