Convenient synthesis, anticancer evaluation and QSAR studies of some thiazole tethered indenopyrazoles

Abstract

A convenient one-pot synthesis of twelve new thiazole tethered indeno[1,2-c]pyrazol-4-ones (3a–3l) was carried out by three-component reaction between 1,3-diketones, thiosemicarbazide and α-bromoketones in high yields. Wolff-Kishner reduction of indeno[1,2-c]pyrazol-4-ones (3a–3l) led to the formation of corresponding indeno[1,2-c]pyrazoles (4a–4l) in moderate-to-good yields. The structures of all the synthesized indenopyrazoles were elucidated by IR, 1H NMR, 13C NMR and mass spectral techniques. In vitro cytotoxicity of thiazole tethered indenopyrazoles (3a–3l & 4a–4l) was evaluated against different human cancer cell lines, viz. human renal carcinoma (A498), human colorectal adenocarcinoma (HT29), human breast adenocarcinoma (MCF-7), human hepatocellular carcinoma (HepG2) and normal cell line, i.e., normal rat kidney epithelial (NRK). Among all the tested derivatives, 4a, 4d and 4h exhibited better activity against HT29 cancer cell line. The statistically significant QSAR models were developed for all the cancer cell lines using multiple linear regression analysis to understand the observed activity trend on structural basis.