Application of an "inhalation by design" approach to the identification and in-vitro evaluation of novel purine based PI3Kδ inhibitors.

PI3Kδ is a lipid kinase which plays a key role in airway inflammatory conditions. Accordingly, the inhibition of PI3Kδ can be considered a valuable strategy for the treatment of chronic respiratory diseases such as Asthma and Chronic obstructive pulmonary disease (COPD). In this work, we describe our efforts to identify new PI3Kδ inhibitors following an "inhalation by design" strategy. Starting from the identification of a purine scaffold, we carried out a preliminary SAR expansion which led to the identification of a new hit characterized by a high enzymatic potency and moderate PI3Kδ selectivity. A subsequent optimization led to novel purine based derivatives with favorable in vitro ADME profiles, which might represent promising starting points for future development of new inhaled drug candidates.

Discovery of Clinical Candidate CHF-6366: A Novel Super-soft Dual Pharmacology Muscarinic Antagonist and ß2 Agonist (MABA) for the Inhaled Treatment of Respiratory Diseases.

The development of molecules embedding two distinct pharmacophores acting as muscarinic antagonists and ß2 agonists (MABAs) promises to be an excellent opportunity to reduce formulation issues and boost efficacy through cross-talk and allosteric interactions. Herein, we report the results of our drug discovery campaign aimed at improving the therapeutic index of a previous MABA series by exploiting the super soft-drug concept. The incorporation of a metabolic liability, stable at the site of administration but undergoing rapid systemic metabolism, to generate poorly active and quickly eliminated fragments was pursued. Our SAR studies yielded MABA 29, which demonstrated a balanced in vivo profile up to 24 h, high instability in plasma and the liver, as well as sustained exposure in the lung. In vitro safety and non-GLP toxicity studies supported the nomination of 29 (CHF-6366) as a clinical candidate, attesting to the successful development of a novel super-soft MABA compound.

Ligand-free Pd/Ag-mediated dehydrogenative alkynylation of imidazole derivatives.

A variety of 2-alkynyl(benzo)imidazoles have been synthesized by dehydrogenative alkynylation of (benzo)imidazoles with terminal alkyne in NMP under air in the presence of Ag2CO3 as the oxidant and Pd(OAc)2 as the catalyst precursor. The data obtained in this study support a reaction mechanism involving a non-concerted metalation deprotonation (n-CMD) pathway.

Atropisomerism and Conformational Equilibria: Impact on PI3Kδ Inhibition of 2-((6-Amino-9H-purin-9-yl)methyl)-5-methyl-3-(o-tolyl)quinazolin-4(3H)-one (IC87114) and Its Conformationally Restricted Analogs.

IC87114 [compound 1, (2-((6-amino-9H-purin-9-yl)methyl)-5-methyl-3-(o-tolyl)quinazolin-4(3H)-one)] is a potent PI3K inhibitor selective for the δ isoform. As predicted by molecular modeling calculations, rotation around the bond connecting the quinazolin-4(3H)-one nucleus to the o-tolyl is sterically hampered, which leads to separable conformers with axial chirality (i.e., atropisomers). After verifying that the aS and aR isomers of compound 1 do not interconvert in solution, we investigated how biological activity is influenced by axial chirality and conformational equilibrium. The aS and aR atropisomers of 1 were equally active in the PI3Kδ assay. Conversely, the introduction of a methyl group at the methylene hinge connecting the 6-amino-9H-purin-9-yl pendant to the quinazolin-4(3H)-one nucleus of both aS and aR isomers of 1 had a critical effect on the inhibitory activity, indicating that modulation of the conformational space accessible for the two bonds departing from the central methylene considerably affects the binding of compound 1 analogues to PI3Kδ enzyme.

Gene expression and biochemical changes of carbohydrate metabolism in in vitro micro-propagated apple plantlets infected by 'Candidatus Phytoplasma mali'.

'Candidatus Phytoplasma mali' (Ca. P. mali) is the disease agent causing apple proliferation (AP), which has detrimental effects on production in many apple growing areas of Central and Southern Europe. The present study investigated transcriptional and biochemical changes related to the sugar metabolism as well as expression of pathogenesis-related (PR) protein genes in in vitro micro-propagated AP-infected and healthy control plantlets with the aim of shedding light on host plant response to 'Ca. P. mali' infection. Expression changes between infected and control plantlets were detected by quantitative real-time PCR analysis. The most significant transcriptional changes were observed for genes coding for pathogenesis-related proteins and for heat shock protein 70, as well as for some genes related to the sugar metabolism, such as a sorbitol transporter (SOT5), hexokinase, sucrose-phosphate synthase or granule bound starch synthase. Furthermore, biochemical analyses revealed that infected plantlets were characterized by a significant accumulation of starch and sucrose, while hexoses, such as glucose and fructose, and sorbitol were present at lower concentrations. In summary, the present analysis provides an overview of a gene set that is involved in response to phytoplasma infection and, therefore, it may help for a better understanding of the molecular mechanisms involved in phytoplasma-host plant interaction in apple.

The identification of a series of novel, soluble non-peptidic neuropeptide Y Y2 receptor antagonists.

The identification and subsequent optimisation of a selective non-peptidic NPY Y2 antagonist series is described. This led to the development of amine 2, a selective, soluble NPY Y2 receptor antagonist with enhanced CNS exposure.

Discovery of 1-(3-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}phenyl)-2-imidazolidinone (GSK163090), a Potent, selective, and orally active 5-HT1A/B/D receptor antagonist.

In an effort to identify selective drug like pan-antagonists of the 5-HT1 autoreceptors, studies were conducted to elaborate a previously reported dual acting 5-HT1 antagonist/SSRI structure. A novel series of compounds was identified showing low intrinsic activities and potent affinities across the 5-HT1A, 5-HT1B, and 5-HT1D receptors as well as high selectivity against the serotonin transporter. From among these compounds, 1-(3-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}phenyl)-2-imidazolidinone (36) was found to combine potent in vivo activity with a strong preclinical developability profile, and on this basis it was selected as a drug candidate with the aim of assessing its potential as a fast-onset antidepressant/anxiolytic.

Design, synthesis and SAR of a novel series of benzimidazoles as potent NPY Y5 antagonists.

A novel class of benzimidazole NPY Y5 receptor antagonists was prepared exploiting a privileged spirocarbamate moiety. The structure-activity relationship of this series and efforts to achieve a profile suitable for further development and an appropriate pharmacokinetic profile in rat are described. Optimisation led to the identification of the brain penetrant, orally bioavailable Y5 antagonist 9b which significantly inhibited the food intake induced by a Y5 selective agonist with a minimal effective dose of 30mg/kg po.

Discovery and structure-activity relationship of a novel spirocarbamate series of NPY Y5 antagonists.

A novel series of trans-8-aminomethyl-1-oxa-3-azaspiro[4.5]decan-2-one derivatives was identified with potent NPY Y5 antagonist activity. Optimization of the original lead furnished compounds 23p and 23u, which combine sub-nanomolar Y5 activity with metabolic stability, oral bioavailability, brain penetration and strong preclinical profile for development. Both compounds significantly inhibited the food intake induced by a Y5 selective agonist with minimal effective doses of 3mg/kg po.

Synthesis and structure-activity relationship of N-(3-azabicyclo[3.1.0]hex-6-ylmethyl)-5-(2-pyridinyl)-1,3-thiazol-2-amines derivatives as NPY Y5 antagonists.

A novel class of small molecule NPY Y5 antagonists based around an azabicyclo[3.1.0]hexane scaffold was identified through modification of a screening hit. Structure-activity relationships and efforts undertaken to achieve a favourable pharmacokinetic profile in rat are described.

The identification and optimisation of novel and selective diamide neuropeptide Y Y2 receptor antagonists.

A novel small molecule NPY Y2 antagonist (3) identified from high throughput screening is described. A subsequent SAR study and optimisation programme based around this molecule is also described, leading to the identification of potent and soluble pyridyl analogue 36.