S. Naveen Kumar

Selective hydrogenation of levulinic acid to γ-valerolactone over a Ru/Mg–LaO catalyst

Ruthenium supported on magnesium–lanthanum mixed oxide (Ru/Mg–LaO) obtained from Mg–La hydrotalcite (a base support) catalyzes the hydrogenation of biomass derived levulinic acid (LA) to γ-valerolactone (GVL). The conversion of LA to GVL in toluene was found to be 92% with the selectivity >99% at 80 °C and 0.5 MPa hydrogen pressure in 4 h. It is the first example on the basic support under mild reaction conditions. The Ru nanoparticles on the Mg–LaO support exhibited excellent GVL yields for 5 cycles, making it a sustainable process.

Effective utilization of glycerol for the synthesis of 2-methylpyrazine over ZnO-ZnCr2O4 catalyst

AbstractBioglycerol an inevitable by-product in the production of biodiesel was effectively utilized for the synthesis of 2-methylpyrazine (2-MP) by vapour phase dehydrocyclization with ethylenediamine over ZnO-ZnCr2O4(Zn-Cr-O) mixed oxides. These Zn-Cr-O samples were obtained from hydrotalcite precursors synthesized by precipitation method at different pH (∼7 and 9) and calcination in air at 450°C. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) analysis confirmed the presence of ZnCr2O4 species. Transmission electron microscopy (TEM) images indicated spherical particles with mean diameter of 35.8 and 24 nm for the Zn-Cr-O prepared at pH ∼ 7 and ∼9, respectively. Surface Zn enrichment was observed in the near-surface region of Zn-Cr-O prepared at pH ∼9. Differences in dehydrocyclization activity of Zn-Cr-O mixed oxides were established based on spectroscopic data that emphasized changes in structural properties of Zn-Cr-O obtained at different pH. ᅟDehydrocyclization of glycerol and ethylenediamine proceeded through a cyclic transition of 2-pyrazinylmethanol to produce 2-methylpyrazine.

Erratum to: Synthesis and characterization of new s-triazine bearing benzimidazole and benzothiazole derivatives as anticancer agents

Erratum to: Med Chem Res (2015) 24:3991–4001DOI 10.1007/s00044-015-1430-9

First total synthesis of fuzanins C, D and their analogues as anticancer agents

The first total synthesis of fuzanins C and D, isolated from the culture supernatant of Kitasatospora sp. IFM10917, is described. Key features of this synthetic strategy involve the use of Sharpless asymmetric epoxidation, dihydroxylation, Mitsunobu reaction and Julia-Kocienski olefination. The total synthesis reported herein also confirmed the absolute configuration of fuzanin D. The optical rotations of synthesized fuzanin D and natural product were opposite in sign, leading to a revision of the reported structure as its enantiomer which is further confirmed by molecular modeling studies. In addition, we also synthesized the analogues of fuzanins C, D containing the quinoline nucleus. All of the synthesized compounds were screened for anticancer activity on four cell lines and found to be potent against HT29 colon cancer cell lines, whereas they were found to be less potent against cervical and breast cancer cell lines.