shows the synthesis of imidazole intermediates and The key p

shows the synthesis of imidazole intermediates , , and . The key precursor keto aldehyde – was prepared in situ by SeO mediated oxidation of corresponding carbonyl compounds and or hydrolysis of dibromo ketone . Subsequent treatment with -Boc piperidine-4-carbaldehyde in the presence of aqueous NHOH afforded the respective imidazoles in good yield. Shown in , is a convergent synthetic route to final compounds –. The key intermediates – were made by reacting imidazole – and with 1-chloro ethyl pyrrolidine HCl salt in the presence of base resulted in alkylated imidazole derivatives –, followed by trifluoroacetic Sanguinarine chloride mediated deprotection gave the corresponding piperidines. With the requisite piperidine amine and chiral Core in hand, preparation of the desired compounds was accomplished by base promoted SNAr reaction to give –. In summary, we have outlined the optimization of to advanced molecules such as using a combination of both structure- and physical-property-based design parameters. We have identified chiral dihydropyridopyrimidinone as a unique kinase inhibitor scaffold of AKT with ROCK2 selectivity, the pharmacological activity resides almost exclusively in the ()-enantiomer. In addition, the cyclic amine pyrrolidine provided optimum AKT potency and metabolic stability. Furthermore, the aliphatic substituent in place of the aryl ring of the imidazole lead served non planar system and to provide a platform for optimizing the physical properties of the resulting molecules. During lead optimization, changes in LogP highlighted valuable structural modifications and restrained the overuse of lipophilicity, which ultimately provided more balanced molecules. As a result, was investigated elaborately for preclinical development and represents a broadly selective, potent, ATP-competitive AKT inhibitor. Acknowledgements
Introduction The HMG-box protein 1 (HBP1) is a ubiquitous transcriptional regulator that belongs to the high mobility group (HMG) family of DNA-binding proteins [1]. HBP1 represses the transcription of target genes, such as cyclin D1 (CCND1), the NADPH oxidase subunit P47phox (NCF1), DNA-methyltransferase 1 (DNMT1) and N-Myc (MYCN) by binding to promoter cis-regulatory elements [[2], [3], [4], [5]]. HBP1 also decreases gene expression indirectly by inhibiting transcription factors, such as c-MYC and TCF4 [4,6,7]. Most HBP1 target genes are related to the cell cycle, which is potently inhibited by HBP1 activation, as demonstrated in numerous cell lines [3,[8], [9], [10]]. In mice, HBP1 deficiency shortens the neuronal cell cycle during cortical development [11]. HBP1 is also required for cell cycle arrest upon Ras-induced premature senescence [12]. In this process, HBP1 up-regulates p16INK4A (CDKN2A) expression, suggesting that it can also act as a transcriptional activator [13]. In agreement with its role as a cell cycle inhibitor, HBP1 was suggested to act as a tumor suppressor. The HBP1 gene maps to chromosome 7q31, a region that is frequently deleted in myeloid cancers and contains several tumor suppressor candidates [14,15]. Alterations of the HBP1 gene were suggested in invasive breast cancers, but this has not been confirmed yet in large scale breast cancer sequencing studies [16]. HBP1 expression is also decreased in a subset of breast cancers and several other tumor types, compared to matched normal tissues. In glioma, for instance, HBP1 is down-regulated by two micro-RNAs, miR-96 and miR-155, resulting in increased cell proliferation [17,18]. We showed that HBP1 transcription is also inhibited by growth factor signaling via the PI3K-AKT oncogenic pathway in multiple cell types [8]. This effect depends on the inactivation of FOXO transcription factors by AKT phosphorylation, which prevents HBP1 promoter activation [8,19]. Interestingly, AKT was also suggested to phosphorylate HBP1, in a study by Cantley and colleagues, who identified a number of potential AKT substrates using a library screening [20]. In the present study, we investigated the phosphorylation of HBP1 by AKT. We found that AKT phosphorylated HBP1 directly, which reduced its transcriptional activity and promoted glioblastoma cell proliferation and transformation. Our data provide a new mechanism by which AKT regulates HBP1 and the cell cycle.