Higher throughput screening of our in house compound collection versus Aurora A offered the imidazopyrazine derivatives and as promising hits . Having confirmed the Aurora A inhibitory activity of and as . and lM, respectively, we initiated a hit to lead programme aimed at establishing clear construction action relationship trends in relation to enzyme inhibition and identifying a compound series meriting additional optimisation in direction of a preclinical growth candidate. To attain these targets, we to start with attempted to establish the position from the C NH with the imidazo pyrazine template for enzyme inhibition. Subsequently, we investigated the Aurora A inhibitory effect of C, C and C substituents about the scaffold .
Starting from , dibromoimidazo pyrazine which was synthesised by modifying a previously reported preparation, access was readily gained to , disubstituted derivatives and , a h along with a g , by initially introducing the amino group at C by way of a SNAr substitution reaction followed by C C bond formation beneath common Suzuki cross coupling ailments . The amide derivatives h, Quizartinib 950769-58-1 i were obtained in the aniline g by response with all the requisite acid chloride from the presence of diisopropylethylamine. The ureas j and k were synthesised by reacting the aniline g with the acceptable aryl isocyanate in CHCl. The sulfonamides l and m have been prepared by treating the aniline g with methoxybenzenesulfonyl chloride and pyridine sulfonyl chloride, respectively, in pyridine CHCl .
The methylimidazo pyrazine derivative was accessed by way of the route proven in Scheme by changing with , dibromo methylimidazo pyrazine which was ready from amino , dibromopyrazine selleck chemical recommended you read inside a manner comparable to that reported for your synthesis of bromo chloro methylimidazo pyrazine. The syntheses in the bromo , chloro , and imidazo pyrazine based analogues are shown in Scheme . Tribromoimidazo pyrazine was obtained from , dibromoimidazo pyrazine upon remedy with NBS Access to , dibromo chloroimidazo pyrazine was accomplished inside a comparable manner to but utilizing NCS. A Suzuki cross coupling amongst and pyridylboronic acid pinacol ester gave the Br derivative in yield, and also the analogue in yield . The assignment of regiochemistry in was confirmed by a Pd catalysed debromination of with triethylsilane The product or service of this response had a H NMR identical to that of a sample of obtained via the route proven in Scheme .
In an work to establish the importance of C NH for enzyme binding, the C N methyl derivative of was ready by way of the route shown in Scheme . Compound displayed reduced Aurora A inhibitory potency relative to , indicating that C NH plays a role in binding to Aurora A, a plausible explanation currently being a hydrogen bonding interaction together with the hinge region on the kinase.