We envisioned using the pyrazole moiety of our thienopyridine series being a phenyl substitute for which would give novel pyrimidine pyrazoles such as compound ; modeling of this compound with Aurora B indicated that the pyrazole ring would produce a distinctive interaction with all the ?extended hinge? region related to that in the thienopyridine series and perhaps provide inhibitors with enhanced potency or efficacy versus . Herein is described the hard work to organize the compounds of general structure so as to decide the impact of modification substitute on the norbornene carboxamide, pyrimidine substituent and pyrazole N substituent on potency, solubility and tumor efficacy. The planning of racemic pyrazole pyrimidine is shown in Scheme and exemplifies the preparation on the vast majority with the compounds in this deliver the results.
Boc protection of commercially out there, racemic, norbornadiene based lactam supplied carbamate which was ring opened with ammonia to present, just after amine deprotection with TFA, norbornene carboxamide in large yield. Addition of to , dichloro fluoropyrimidine URB597 clinical trial inside the presence of sodium bicarbonate regioselectively gave chloropyrimidine which was treated with methyl aminopyrazole and hydrochloric acid at C to afford pyrazole pyrimidine . Diversity might be introduced into this structure by replacement of ammonia with key amines in the ring opening stage, replacement within the fluoropyrimidine with other substituted pyrimidines and use of aminopyrazoles having a number of N substituents. Selected analogs had been resynthesized as the single enantiomer implementing carboxamide .
The common preparation from the pyrimidine analogs is proven in Scheme . Since the addition of amine to , dichloro pyrimidine was not regioselective, a route was utilized to prepare pyrimidines that Ubiquinone entailed a ZnCl mediated, remarkably regioselective addition of methyl aminopyrazole towards the position of pyrimidine to provide intermediate in modest yield. Addition of amine to chloropyrimidine from the presence of Hunig?s base at C gave the preferred pyrimidine in substantial yield. This route proved convenient for your original perform on norbornene carboxamide substitute. The prepared analogs had been assessed for enzymatic action against a panel of kinases such as KDR, Aurora B, Flt , Flt , cKit, CSFR and FGFR; compounds with enough KDR and Aurora B enzymatic action have been examined for cellular activity in the KDR autophosphorylation assay in addition to a polyploidy induction assay indicative of Aurora B exercise.
Selected inhibitors were then assessed inside a xenograft mouse tumor model implementing the DoHH cancer cell line. As proven in Inhibitors , while pyrazole pyrimidine was only a modest inhibitor of KDR and a lot less lively than thienopyridine pyrazole , it had been comparable in potency to diaminopyrimidine in each the KDR and Aurora B enzymatic assays.