Automated Synthesis for the Safe Production of Organic Azides from Primary Amines.

Described herein is the development of an automated and reproducible process for the conversion of primary amines to organic azides utilizing prepacked capsules containing all the required reagents, including imidazole-1-sulfonyl azide tetrafluoroborate. Apart from manually loading the primary amine into the reaction vessel, the entire reaction and product isolation process can be achieved automatically, with no further user involvement, and delivers the desired organic azide in high purity. This practical and simple automated capsule-based method offers a convenient and safe way of generating organic azides without handling or exposure of potentially explosive reagents.

Automated and enabling technologies for medicinal chemistry.

Having always been driven by the need to get new treatments to patients as quickly as possible, drug discovery is a constantly evolving process. This chapter will review how medicinal chemistry was established, how it has changed over the years due to the emergence of new enabling technologies, and how early advances in synthesis, purification and analysis, have provided the foundations upon which the current automated and enabling technologies are built. Looking beyond the established technologies, this chapter will also consider technologies that are now emerging, and their impact on the future of drug discovery and the role of medicinal chemists.

Cartridge-based Automated Synthesis - A New Tool for the Synthetic Chemist.

Despite recent advances in reaction methodologies, organic synthesis remains complex and challenging. Many of the fundamental processes in use have not changed in over 100 years, with a large proportion of the work being carried out manually, using lengthy procedures and difficult or hazardous reaction conditions. As such, organic synthesis still presents a bottle-neck in discovery research. Endeavours to automate synthesis in discovery, through robotic platforms, have so far not been widely successful because the highly complex nature of such machines, and the level of skill required for their operation, presents a barrier too great for most discov- ery chemists. Synple Chem has developed a safe, easy to use, efficiency-enhancing automated technology for the acceleration of discovery research. The automated flow-batch hybrid system utilises a range of innovative pre-packed reagent cartridges for different reaction classes, along with pre-programmed, highly optimised but editable reaction protocols. The combination of these three key elements, provides users with a convenient, easy to use, time-saving technology that makes the synthesis of molecules far simpler, faster and more efficient. The described technology offers all discovery chemists access to real synthesis automation without any of the barriers that have previously restricted its utility.

Structure-Activity Relationship of the GPR55 Antagonist, CID16020046.

BACKGROUND/AIMS: CID16020046 blocks the effect of the lipid lysophosphatidylinositol (LPI) at its receptor, GPR55. CID16020046 and another antagonist, ML193, have been used to investigate GPR55-mediated effects of LPI on cells, tissues, and in vivo. Here we describe the structure-activity relationship of CID16020046. METHODS: Yeast or human cells were engineered to express GPR55 or control receptors. Cells were pretreated with a test agent before agonist challenge. Functional responses were quantified by yeast gene-reporter or calcium imaging. RESULTS: Three substituents around the central pyrazololactam core of CID16020046 are each tolerant to substitution without abolishing GPR55 activity. Analogues of CID16020046 with potency at GPR55 ranging >1,000-fold are described, including several lacking activity up to the top concentration tested. One analogue, compound 1 (GSK875734A), has approximately 50-fold greater potency than CID16020046 in an inverse agonist assay. CID16020046, ML193 and 2 further antagonists (ML191 and ML192) all block the effect of a surrogate agonist at human GPR55. ML193, CID16020046 and several other examples of the pyrazololactam chemotype were also shown to antagonise rat GPR55. CONCLUSION: These data confirm the utility of CID16020046 and ML193 as tools to investigate the physiological role of GPR55, and offer starting points for GPR55 antagonists with optimised pharmacokinetic or other properties.

Discovery of 5-substituent-N-arylbenzamide derivatives as potent, selective and orally bioavailable LRRK2 inhibitors.

Leucine-rich repeat kinase 2 (LRRK2) has been suggested as a potential therapeutic target for Parkinson's disease. Herein we report the discovery of 5-substituent-N-arylbenzamide derivatives as novel LRRK2 inhibitors. Extensive SAR study led to the discovery of compounds 8e, which demonstrated potent LRRK2 inhibition activity, high selectivity across the kinome, good brain exposure, and high oral bioavailability.

Automated, Capsule-Based Suzuki-Miyaura Cross Couplings.

The development of an automated process for Suzuki-Miyaura cross couplings is described, in which the complete reaction, workup, and product isolation are effected automatically with no user involvement, aside from loading of the starting materials and reaction capsule. This practical and simple method was successfully demonstrated to provide the desired biaryl products using a range of aryl bromides and boronic acids and is also effective for the late-stage functionalization of aryl halides in bioactive molecules.

A vending machine for drug-like molecules - automated synthesis of virtual screening hits.

As a result of high false positive rates in virtual screening campaigns, prospective hits must be synthesised for validation. When done manually, this is a time consuming and laborious process. Large "on-demand" virtual libraries (>7 × 1012 members), suitable for preparation using capsule-based automated synthesis and commercial building blocks, were evaluated to determine their structural novelty. One sub-library, constructed from iSnAP capsules, aldehydes and amines, contains unique scaffolds with drug-like physicochemical properties. Virtual screening hits from this iSnAP library were prepared in an automated fashion for evaluation against Aedes aegypti and Phytophthora infestans. In comparison to manual workflows, this approach provided a 10-fold improvement in user efficiency. A streamlined method of relative stereochemical assignment was also devised to augment the rapid synthesis. User efficiency was further improved to 100-fold by downscaling and parallelising capsule-based chemistry on 96-well plates equipped with filter bases. This work demonstrates that automated synthesis consoles can enable the rapid and reliable preparation of attractive virtual screening hits from large virtual libraries.

Pharmacology of GPR55 in yeast and identification of GSK494581A as a mixed-activity glycine transporter subtype 1 inhibitor and GPR55 agonist.

GPR55 is a G protein-coupled receptor activated by L-α-lysophosphatidylinositol and suggested to have roles in pain signaling, bone morphogenesis, and possibly in vascular endothelial cells. It has affinity for certain cannabinoids (molecules that interact with the cannabinoid CB(1) and CB(2) receptors), but investigation of its functional role in cell-based systems and in tissue has been limited by a lack of selective pharmacological tools. Here, we present our characterization of GPR55 in the yeast Saccharomyces cerevisiae and in human embryonic kidney (HEK293) cells. We describe GSK494581A (1-{2-fluoro-4-[1-(methyloxy)ethyl]phenyl}-4-{[4'-fluoro-4-(methylsulfonyl)-2-biphenylyl]carbonyl}piperazine), a selective small-molecule ligand of GPR55 identified through diversity screening. GSK494581A is one of a series of benzoylpiperazines originally identified and patented as inhibitors of the glycine transporter subtype 1 (GlyT1). The structure-activity relationship between GPR55 and GlyT1 is divergent across this series. The most GPR55-selective example is GSK575594A (3-fluoro-4-(4-{[4'-fluoro-4-(methylsulfonyl)-2-biphenylyl]carbonyl}-1-piperazinyl)aniline), which is approximately 60-fold selective for GPR55 (pEC(50) = 6.8) over GlyT1 (pIC(50) = 5.0). Several exemplars with activity at GPR55 and GlyT1 have been profiled at a broad range of other molecular targets and are inactive at cannabinoid receptors and all other targets tested. The benzoylpiperazine agonists activate human GPR55 but not rodent GPR55, suggesting that the relatively low level of sequence identity between these orthologs (75%) translates to important functional differences in the ligand-binding site.

An integrated console for capsule-based, automated organic synthesis.

The current laboratory practices of organic synthesis are labor intensive, impose safety and environmental hazards, and hamper the implementation of artificial intelligence guided drug discovery. Using a combination of reagent design, hardware engineering, and a simple operating system we provide an instrument capable of executing complex organic reactions with prepacked capsules. The machine conducts coupling reactions and delivers the purified products with minimal user involvement. Two desirable reaction classes - the synthesis of saturated N-heterocycles and reductive amination - were implemented, along with multi-step sequences that provide drug-like organic molecules in a fully automated manner. We envision that this system will serve as a console for developers to provide synthetic methods as integrated, user-friendly packages for conducting organic synthesis in a safe and convenient fashion.

Potent oxadiazole CGRP receptor antagonists for the potential treatment of migraine.

A pharmacophore model was built, based on known CGRP receptor antagonists, and this was used to aid the identification of novel leads. Analogues were designed, modelled and synthesised which incorporated alternative 'LHS' fragments linked via either an amide or urea to a privileged 'RHS' fragment commonly found in CGRP receptor antagonists. As a result a novel series of oxadiazole CGRP receptor antagonists has been identified and the subsequent optimisation to enhance both potency and bioavailability is presented.