Synthetic, Structural, and Anticancer Activity Evaluation Studies on Novel Pyrazolylnucleosides

Yadav, Yogesh; Sharma, Deepti; Kaushik, Kumar; Kumar, Vineet; Jha, Amitabh; Prasad, Ashok K.; Len, Christophe; Malhotra, Sanjay V.; Wengel, Jesper; Parmar, Virinder S.

Reactions were conducted under an atmosphere of nitrogen in anhydrous solvents. Column chromatography was carried out by using silica gel (100-200 mesh). Melting points were determined in a concentrated H 2 SO 4 acid bath and were uncorrected. Analytical TLCs were performed on pre-coated Merck silica gel 60F 254 plates; the spots were detected either by using UV light or by charring with 4% alcoholic sulfuric acid. The IR spectra were recorded on a Perkin-Elmer 2000 FT-IR spectrophotometer (Waltham, MA, USA). The optical rotations were measured with a Bellingham-Stanley AD 220 polarimeter and the concentrations expressed as g/mL. The 1 H-NMR and 13 C-NMR spectra were recorded on a Bruker Avance 300 spectrometer (Billerica, MA, USA) at 300 and 75.5 MHz, respectively in CDCl 3 , DMSO-d 6 , or CD 3 CN. All 2D measurements were performed in acetone-d 6 on a Bruker Avance 400 spectrometer (Billerica, MA, USA). Chemical shifts are relative to internal TMS. Assignments were based on COSY, NOESY, HMBC (by using Bruker's microprogram inv4gslplrnd, which includes the low-pass J-filter to suppress one-bond correlations), HSQC, and JRES spectra. The chemical shift values were reported as δ ppm relative to TMS used as the internal standard and the coupling constants (J) were measured in Hz. The ESI-HRMS spectra of all compounds were recorded on a JEOL JMS-AX505W high-resolution mass spectrometer (Tokyo, Japan) in positive ion mode by using the matrix HEDS (bis-hydroxyethylsulfide) doped with sodium acetate. Acetonitrile was used after distillation over freshly ignited potassium carbonate.