Synthesis and Antitumor Activity of Guanylhydrazones from 6-(2,4-Dichloro-5-nitrophenyl)imidazo[2,1-<i>b</i>]thiazoles and 6-Pyridylimidazo[2,1-<i>b</i>]thiazoles
The design and synthesis of antitumor imidazothiazole guanylhydrazones are reported. The compounds were submitted to NCI for testing. All but one were more active than methyl-GAG. A few compounds were selected for further studies in search of a possible mechanism of action. The results from these studies and a final search with the NCI COMPARE algorithm suggest that the guanylhydrazones described in
The synthesis, characterization, and functional in vitro assay in cardiac and smooth muscle (vascular and nonvascular) of a series of 4-imidazo[2,1-b]thiazole-1,4-dihydropyridines are reported. To define the calcium blocker nature of the imidazo[2,1-b]thiazole-1,4-DHPs and their selectivity on Ca(v)1.2 and Ca(v)1.3 isoforms, we performed binding studies on guinea pig atrial and ventricular membranes on intact cells expressing the cloned Ca(v)1.2a subunit and on rat brain cortex. To get major insights into the reasons for the affinity for Ca(v)1.2 and/or Ca(v)1.3, molecular modeling studies were also undertaken. Some physicochemical and pharmacokinetic properties of selected compounds were calculated and compared. All the biological data collected and reported herein allowed us to rationalize the structure-activity relationship of the 4-imidazo[2,1-b]thiazole-1,4-DHPs and to identify which of these enhanced the activity at the central level.