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Ghrelin plays a major physiological role in the control of food intake, and inverse agonists of the ghrelin receptor (GHS-R1a) are widely considered to offer utility as antiobesity agents by lowering the set-point for hunger between meals. We identified an acylurea series of ghrelin modulators from high throughput screening and optimized binding affinity through structure-activity relationship studies. Furthermore, we identified specific substructural changes, which switched partial agonist activity to inverse agonist activity, and optimized physicochemical and DMPK properties to afford the non-CNS penetrant inverse agonist 22 (AZ-GHS-22) and the CNS penetrant inverse agonist 38 (AZ-GHS-38). Free feeding efficacy experiments showed that CNS exposure was necessary to obtain reduced food intake in mice, and it was demonstrated using GHS-R1a null and wild-type mice that this effect operates through a mechanism involving GHS-R1a.

3,3-Di-methyl-azetidin-2-ones were identified as potent and selective 11β-HSD1 inhibitors against the human and mouse forms of the enzyme. Structure guided optimisation of LLE was conducted, utilising a key polar interaction and identifying stereochemical preference for the 4S isomer. Metabolic stability was improved to afford oral exposure, providing tool compounds suitable for pre-clinical evaluation.

At AstraZeneca a focus on hypothesis-driven design and the formation of drug design teams has placed a greater emphasis on collaboration in the drug discovery process. We have created a novel software tool based on the principles of wikis and social networks to facilitate collaborative working, visual planning and incorporation of predictive science to improve design capability. Monitoring the design and make process via the tool enabled the identification of bottlenecks and delays. Solutions to these problems were implemented, reducing the time taken from the initial idea stage to the generation of the synthesised compound by more than 50%.

Checkpoint Kinase-1 (Chk1, CHK1, CHEK1) is a Ser/Thr protein kinase that mediates cellular responses to DNA-damage. A novel class of Chk1 inhibitors, triazoloquinolones/triazolones (TZ's) was identified by high throughput screening. The optimization of these hits to provide a lead series is described.

Deregulation of the cell cycle has long been recognized as an essential driver of tumorigenesis, and agents that selectively target key cell cycle components continue to hold promise as potential therapeutics. We have developed AZD5438, a 4-(1-isopropyl-2-methylimidazol-5-yl)-2-(4-methylsulphonylanilino) pyrimidine, as a potent inhibitor of cyclin-dependent kinase (cdk) 1, 2, and 9 (IC50, 16, 6, and 20 nmol/L, respectively). In vitro, AZD5438 showed significant antiproliferative activity in human tumor cell lines (IC50 range, 0.2–1.7 μmol/L), causing inhibition of the phosphorylation of cdk substrates pRb, nucleolin, protein phosphatase 1a, and RNA polymerase II COOH-terminal domain and blocking cell cycling at G2-M, S, and G1 phases. In vivo, when orally administered at either 50 mg/kg twice daily or 75 mg/kg once daily, AZD5438 inhibited human tumor xenograft growth (maximum percentage tumor growth inhibition, range, 38–153; P < 0.05). In vivo, AZD5438 reduced the proportion of actively cycling cells. Further pharmacodynamic analysis of AZD5438-treated SW620 xenografts showed that efficacious doses of AZD5438 (>40% tumor growth inhibition) maintained suppression of biomarkers, such as phospho-pRbSer249/Thr252, for up to 16 hours following a single oral dose. A comparison of different schedules indicated that chronic daily oral dosing provided optimal cover to ensure antitumor efficacy. These data indicate that broad cdk inhibition may provide an effective method to impair the dysregulated cell cycle that drives tumorigenesis and AZD5438 has the pharmacologic profile that provides an ideal probe to test this premise. [Mol Cancer Ther 2009;8(7):1856–66]

Checkpoint kinase-1 (Chk1, CHEK1) is a Ser/Thr protein kinase that mediates the cellular response to DNA-damage. A novel class of 2-ureido thiophene carboxamide urea (TCU) Chk1 inhibitors is described. Inhibitors in this chemotype were optimized for cellular potency and selectivity over Cdk1.

Triazine based antibiotics were prepared by the attachment of cyanuric chloride onto a Marshall-type safety catch linker, followed by successive aromatic nucleophilic substitutions, linker activation and nucleophilic cleavage. High-loading dendrimer beads allowed the release of sufficient amount of compound from a single bead to give clear inhibition.

Solid-phase dendrimer chemistry using a symmetrical 1→3C-branched isocyanate monomer was used to prepareradiation-grafted polymers with enhanced loading. Afterevaluation of the physical and chemical properties of thesenew high-loading supports, they were tested in the multipleparallel synthesis of hydantoins.

Resins with loading up to 96 nmol/bead were prepared by solid-phase dendrimerisation using a symmetrical 1→3 C-branched isocyanate monomer.

High loading resins (up to 120 nmoles/bead) were preprared by solid-phase dendrimerisation using a novel 1→3 C-branched isocyanate monomer.

The synthesis and directed dihydroxylation of a series of homoallylic alcohols and trichloroacetamides is described. Using the combination of OsO4 and TMEDA, moderate to high levels of stereoselectivity were obtained, depending upon the structure of the substrate. Proof of the structure of two osmate esters was obtained through X-ray crystallography. © 2001 Elsevier Science Ltd. All rights reserved.

The preparation and dihydroxylation of a series of polyenes and cyclic allylic alcohols using the TMEDA/osmium tetroxide mixture is reported. Remarkably, these reagents lead to high levels of regiochemical and stereochemical control as the oxidant hydrogen-bonds to the allylic alcohol group. A mechanistic hypothesis is presented which invokes the formation of a reactive, bidentate complex between osmium tetroxide and TMEDA at low temperatures.

Inhibition of 11β-HSD1 is an attractive mechanism for the treatment of obesity and other elements of the metabolic syndrome. We report here the discovery of a nicotinic amide derived carboxylic acid class of inhibitors that has good potency, selectivity, and pharmacokinetic characteristics. Compound 11i (AZD4017) is an effective inhibitor of 11β-HSD1 in human adipocytes and exhibits good druglike properties and as a consequence was selected for clinical development.

Checkpoint kinases CHK1 and CHK2 are activated in response to DNA damage that results in cell cycle arrest, allowing sufficient time for DNA repair. Agents that lead to abrogation of such checkpoints have potential to increase the efficacy of such compounds as chemo- and radiotherapies. Thiophenecarboxamide ureas (TCUs) were identified as inhibitors of CHK1 by high throughput screening. A structure-based approach is described using crystal structures of JNK1 and CHK1 in complex with 1 and 2 and of the CHK1-3b complex. The ribose binding pocket of CHK1 was targeted to generate inhibitors with excellent cellular potency and selectivity over CDK1and IKKβ, key features lacking from the initial compounds. Optimization of 3b resulted in the identification of a regioisomeric 3-TCU lead 12a. Optimization of 12a led to the discovery of the clinical candidate 4 (AZD7762), which strongly potentiates the efficacy of a variety of DNA-damaging agents in preclinical models.

A novel series of DGAT-1 inhibitors was discovered from an oxadiazole amide high throughput screening (HTS) hit. Optimisation of potency and ligand lipophilicity efficiency (LLE) resulted in a carboxylic acid containing clinical candidate 53 (AZD3988), which demonstrated excellent DGAT-1 potency (0.6 nM), good pharmacokinetics and pre-clinical in vivo efficacy that could be rationalised through a PK/PD relationship.

Checkpoint kinase 1 (Chk1, CHEK1) is a Ser/Thr protein kinase that plays a key role in mediating the cellular response to DNA-damage. Synthesis and evaluation of a previously described class of Chk1 inhibitors, triazoloquinolones/triazolones (TZs) is further described herein. Our investigation of structure-activity relationships led to the identification of potent inhibitors 14c, 14h and 16e. Key challenges included modulation of physicochemical properties and pharmacokinetic (PK) parameters to enable compound testing in a Chk1 specific hollow fiber pharmacodynamic model. In this model, 16e was shown to abrogate topotecan-induced cell cycle arrest in a dose dependent manner. The demonstrated activity of TZs in this model in combination with a chemotherapeutic agent as well as radiotherapy validates this series of Chk1 inhibitors. X-ray crystal structures (PDB code: 2YEX and 2YER) for an initial lead and an optimized analog are also presented.

The preparation and dihydroxylation of a series of polyenes and cyclic allylic alcohols using the TMEDA/osmium tetroxide mixture is reported. Remarkably, these reagents lead to high levels of regiochemical and stereochemical control as the oxidant hydrogen-bonds to the allylic alcohol group. A mechanistic hypothesis is presented which invokes the formation of a reactive, bidentate complex between osmium tetroxide and TMEDA at low temperatures.

The first synthesis of (+)-pericosine B is described: this takes seven steps and proceeds in 10% overall yield. The key step in our work is a hydrogen-bonding controlled contra-steric dihydroxylation reaction using osmium tetroxide and an amine promoter. The absolute stereochemistry of the natural product was deduced from the known absolute stereochemistry of our starting material and moreover, the relative and absolute stereochemistry of our synthetic material was determined unambiguously from an X-ray crystal structure of an advanced intermediate.

The preparation and directed dihydroxylation of a series of acyclic allylic alcohols is reported. The oxidation reaction is capable of demonstrating high levels of diastereoselection for the syn isomer. An explanation of the observed selectivities based on the degree of allylic strain is presented and a transition state model proposed.

Potent inhibition of rat microsomal oxidosqualene cyclase-lanosterol synthase (OSC) was maintained after structural modification of the 4-piperidinopyridine OSC inhibitor series. These novel analogues with a much lower pKa range (5.8–6.7) gave potent oral inhibition of rat cholesterol biosynthesis (8 ED80 0.7 mg/kg), and diminished effects on rat feeding after a 100 mg/kg oral dose.

The synthesis and directed dihydroxylation of a series of homoallylic alcohols and trichloroacetamides is described. Using the combination of OsO 4 and TMEDA, moderate to high levels of stereoselectivity were obtained, depending upon the structure of the substrate. Proof of the structure of two osmate esters was obtained through X-ray crystallography.

An imidazole series of cyclin-dependent kinase (CDK) inhibitors has been developed. Protein inhibitor structure determination has provided an understanding of the emerging structure activity trends for the imidazole series. The introduction of a methyl sulfone at the aniline terminus led to a more orally bioavailable CDK inhibitor that was progressed into clinical development.

The oxidation of a range of cyclic allylic alcohols and amides with OsO4/TMEDA is presented. Under these conditions, hydrogen bonding control leads to the (contrasteric) formation of the syn isomer in almost every example that was examined. Evidence for the bidentate binding of TMEDA to OsO4 is presented and a plausible mechanism described.

Potent inhibition of rat microsomal oxidosqualene cyclase-lanosterol synthase (OSC) was maintained after structural modification of the 4-piperidinopyridine OSC inhibitor series. These novel analogues with a much lower pKa range (5.8–6.7) gave potent oral inhibition of rat cholesterol biosynthesis (8 ED80 0.7 mg/kg), and diminished effects on rat feeding after a 100 mg/kg oral dose.