Synthesis of Borylated Carbocycles by [2 + 2]-Cycloadditions and Photo-Ene Reactions.

Saturated bicyclic compounds make up a valuable class of building blocks in the development of agrochemicals and pharmaceuticals. Here, we present the synthesis of borylated bicyclo[2.1.

Synthesis of 2-Azanorbornanes via Strain-Release Formal Cycloadditions Initiated by Energy Transfer.

Rigid bicycles are becoming more popular in the pharmaceutical industry because they allow for expansion to new and unique chemical spaces. This work describes a new strategy to construct 2-azanorbornanes, which can act as rigid piperidine/pyrrolidine scaffolds with well-defined exit vectors. To achieve the synthesis of 2-azanorbornanes, new strain-release reagent, azahousane, is introduced along with its photosensitized strain-release formal cycloaddition with alkenes.

Diversification of Simple Arenes into Complex (Amino)cyclitols.

Highly oxygenated cyclohexanes, including (amino)cyclitols, are featured in natural products possessing a notable range of biological activities. As such, these building blocks are valuable tools for medicinal chemistry. While de novo synthetic strategies have provided access to select compounds, challenges including stereochemical density and complexity have hindered the development of a general approach to (amino)cyclitol structures.

Preparation of 3,5-Methanobenzo[]azepines: An sp-Rich Quinolone Isostere.

The replacement of the aromatic ring in bioactive compounds with saturated bioisosteres has become a popular tactic to obtain novel structures with improved physicochemical profiles. In this paper, we describe an efficient synthesis of 3,5-methanobenzo[]azepine analogues and suggest them as isosteres of quinolones. Quinolones are heteroaromatic, flat rings and considered as privileged scaffolds.

2,5-disubstituted bicyclo[2.1.1]hexanes as rigidified cyclopentane variants.

Identification of rigid counterparts for common flexible scaffolds is crucial to the advancement of medicinal chemistry. Here we showcase a new class of building blocks, 2,5-disubstituted bicyclo[2.1.

Silver(I)-Catalyzed Synthesis of Cuneanes from Cubanes and their Investigation as Isosteres.

Bridged or caged polycyclic hydrocarbons have rigid structures that project substituents into precise regions of 3D space, making them attractive as linking groups in materials science and as building blocks for medicinal chemistry. The efficient synthesis of new or underexplored classes of such compounds is, therefore, an important objective. Herein, we describe the silver(I)-catalyzed rearrangement of 1,4-disubstituted cubanes to cuneanes, which are strained hydrocarbons that have not received much attention since they were first described in 1970.

[2]-Ladderanes as isosteres for meta-substituted aromatic rings and rigidified cyclohexanes.

Aromatic ring isosteres and rigidified saturated hydrocarbons are important motifs to enable drug discovery. Herein we disclose [2]-ladderanes as a class of meta-substituted aromatic ring isosteres and rigidified cyclohexanes. A straightforward synthesis of the building blocks is presented along with representative derivatization.

Strain-Release [2π + 2σ] Cycloadditions for the Synthesis of Bicyclo[2.1.1]hexanes Initiated by Energy Transfer.

Saturated bicycles are becoming ever more important in the design and development of new pharmaceuticals. Here a new strategy for the synthesis of bicyclo[2.1.

Pushing the Frontiers of Accessible Chemical Space to Unleash Design Creativity and Accelerate Drug Discovery.

In highly competitive research environments, the ability to access more complex structural spaces efficiently is a predictor of a company's ability to generate novel IP-protected small molecule candidates with adequate properties, hence filling their development pipelines. SpiroChem is consistently developing new synthetic methodologies and strategies to access complex molecular structure, thereby facilitating and accelerating small molecule drug discovery. Pushing the limits of what are as complex molecular structures allows SpiroChem and its clients to unleash creativity and explore meaningful chemical spaces, which are under-exploited sources of novel active molecules.

Accelerating fragment-based library generation by coupling high-performance photoreactors with benchtop analysis.

Herein we report a workflow coupling photoredox-nickel dual-catalyzed -arylation reactions to benchtop analysis for the efficient generation of fragment-based libraries. Technological advances in photoreactor design facilitated reliable and reproducible experimentation. Knowledge on the reactivity under previously reported reaction conditions of spirocyclic and strained heterocyclic building blocks, viewed as chemistry informers, could thus be rapidly accessed, identifying privileged or challenging scaffolds and paving the way for further exploration.

Activating Pyrimidines by Pre-distortion for the General Synthesis of 7-Aza-indazoles from 2-Hydrazonylpyrimidines via Intramolecular Diels-Alder Reactions.

Pyrimidines are almost unreactive partners in Diels-Alder cycloadditions with alkenes and alkynes, and only reactions under drastic conditions have previously been reported. We describe how 2-hydrazonylpyrimidines, easily obtained in two steps from commercially available 2-halopyrimidines, can be exceptionally activated by trifluoroacetylation. This allows a Diels-Alder cycloaddition under very mild reaction conditions, leading to a large diversity of aza-indazoles, a ubiquitous scaffold in medicinal chemistry.

On water N-arylation of oxetanylamines for the preparation of N-aryl-oxetanylamines; potentially useful aryl-amide isosteres.

A Pd cross-coupling approach for the synthesis of N-aryl-oxetanylamines has been developed. This method provides new building blocks potentially useful in medicinal chemistry as amide bioisosteres. The reactions are conducted in water employing the renewable feedstock surfactant TPGS-750-M.

Domino Pd -Catalyzed C(sp )-H Arylation/Electrocyclic Reactions via Benzazetidine Intermediates.

The Pd -catalyzed C(sp )-H arylation of 2-bromo-N-methylanilides leads to unstable benzazetidine intermediates that rearrange to benzoxazines through 4π electrocyclic ring-opening and 6π electrocyclization. The introduction of a bulky, non-activatable amide group on the nitrogen atom was key to favor the challenging reductive elimination step and disfavor undesired reaction pathways.

Efficient and Mild Ullmann-Type N-Arylation of Amides, Carbamates, and Azoles in Water.

A simple, sustainable, efficient, mild, and low-cost protocol was developed for d-glucose-assisted Cu-catalyzed Ullmann reactions in water for amides, carbamates, and nitrogen-containing heterocycles. The reaction was compatible with diverse aryl/heteroaryl iodides, giving highly substituted pyridine, indole, or indazole rings. This method offers an attractive alternative to existing protocols, because the reaction proceeds in aqueous media, occurs at or near ambient temperature, and provides the N-arylated products in good to high yields.

d-Glucose: An Efficient Reducing Agent for a Copper(II)-Mediated Arylation of Primary Amines in Water.

A copper-catalyzed Ullmann-type amination with primary amines in water with a combination of copper(II) triflate [Cu(OTf) ], dipivaloylmethane, and d-glucose is reported. The mild conditions and the use of an inexpensive catalyst as well as a renewable feedstock (d-glucose and the surfactant TPGS-750-M, which is derived from vitamin E) make this protocol a safe and convenient strategy for efficient C-N bond formation. This easy-to-handle procedure is extremely competitive compared to palladium-based reactions and may be used to synthesize N-containing molecules, such as drugs or organic light-emitting diodes (OLEDs).

Smart tools and orthogonal click-like reactions onto small unilamellar vesicles: Additional molecular data.

We present here the synthetic routes and the experimental data (NMR and MS spectra) for model reactions for copper-free Huisgen 1,4-cycloaddition, Staudinger ligation and for addition of a dithiol on a dibromomaleimide ring. Starting materials were synthesized from the commercially available 4-chlorophenethylamine, previously described 2-(cyclooct-2-yn-1-yloxy)acetic acid, 1-fluorocyclooct-2-ynecarboxylic acid, commercial 2-(diphenylphosphino)terephthalic acid 1-methyl 4-pentafluorophenyl diester and dibromomaleimide. In all cases, the expected compounds were obtained with good yield (50% to quantitative).

Chemical Library Screening and Structure-Function Relationship Studies Identify Bisacodyl as a Potent and Selective Cytotoxic Agent Towards Quiescent Human Glioblastoma Tumor Stem-Like Cells.

Cancer stem-like cells reside in hypoxic and slightly acidic tumor niches. Such microenvironments favor more aggressive undifferentiated phenotypes and a slow growing "quiescent state" which preserves them from chemotherapeutic agents that essentially target proliferating cells. Our objective was to identify compounds active on glioblastoma stem-like cells, including under conditions that mimick those found in vivo within this most severe and incurable form of brain malignancy.

Smart tools and orthogonal click-like reactions onto small unilamellar vesicles.

Click-based reactions were conducted at the surface of small unilamellar vesicles (SUVs) to provide onto-vesicle chemistry with efficient innovative ready-for-use tools. For that purpose, four amphiphilic molecules were designed to insert into bilayers while presenting a reactive functional head. In this manner, a dioleylglycero-ethoxy-ethoxy-ethoxy-ethanamine (DOG-PEG4-NH2) was chosen as a common platform while the reactive amine head was converted into several electrophilic functions.

Benzofuran derivatives as anticancer inhibitors of mTOR signaling.

A series of 32 derivatives and isosteres of the mTOR inhibitor 2 were synthesized and compared for their cytotoxicity in radioresistant SQ20B cancer cell line. Several of these compounds, in particular 30b, were significantly more cytotoxic than 2. Importantly, 30b was shown to block both mTORC1 and Akt signaling, suggesting insensitivity to the resistance associated to Akt overactivation observed with rapamycin derivatives currently used in clinic.

Benzofuran derivatives as a novel class of inhibitors of mTOR signaling.

High-throughput screening (HTS) hit 1 was previously identified as an inhibitor of the Akt/mTOR (Akt/mammalian target of rapamycin) signaling, which is a major target in oncology. The cytotoxicity of 1 was determined on a panel of human cancer cells lines with an IC₅₀ comprised between 30 and 140 μM. Subsequent structure--activity relationship (SAR) studies led us to the identification of compounds that displayed an enhanced cytotoxicity.

Identification of the benzyloxyphenyl pharmacophore: a structural unit that promotes sodium channel slow inactivation.

Four compounds that contained the N-benzyl 2-amino-3-methoxypropionamide unit were evaluated for their ability to modulate Na(+) currents in catecholamine A differentiated CAD neuronal cells. The compounds differed by the absence or presence of either a terminal N-acetyl group or a (3-fluoro)benzyloxy moiety positioned at the 4'-benzylamide site. Analysis of whole-cell patch-clamp electrophysiology data showed that the incorporation of the (3-fluoro)benzyloxy unit, to give the (3-fluoro)benzyloxyphenyl pharmacophore, dramatically enhanced the magnitude of Na(+) channel slow inactivation.

Synthesis, anticonvulsant activity, and neuropathic pain-attenuating activity of N-benzyl 2-amino-2-(hetero)aromatic acetamides.

N-Benzyl 2-acetamido-2-substituted acetamides, where the 2-substituent is a (hetero)aromatic moiety, are potent anticonvulsants. We report the synthesis and whole animal pharmacological evaluation of 16 analogues where the terminal 2-acetyl group was removed to give the corresponding primary amino acid derivatives (PAADs). Conversion to the PAAD structure led to a substantial drop in seizure protection in animal tests, demonstrating the importance of the N-acetyl moiety for anticonvulsant activity.

Primary amino acid derivatives: substitution of the 4'-N'-benzylamide site in (R)-N'-benzyl 2-amino-3-methylbutanamide, (R)-N'-benzyl 2-amino-3,3-dimethylbutanamide, and (R)-N'-benzyl 2-amino-3-methoxypropionamide provides potent anticonvulsants with pain-attenuating properties.

Recently, we reported that select N'-benzyl 2-substituted 2-amino acetamides (primary amino acid derivatives (PAADs)) exhibited pronounced activities in established whole animal anticonvulsant (i.e., maximal electroshock seizure (MES)) and neuropathic pain (i.

Merging Structural Motifs of Functionalized Amino Acids and α-Aminoamides Results in Novel Anticonvulsant Compounds with Significant Effects on Slow and Fast Inactivation of Voltage-gated Sodium Channels and in the Treatment of Neuropathic Pain.

We recently reported that merging key structural pharmacophores of the anticonvulsant drugs lacosamide (a functionalized amino acid) with safinamide (an α-aminoamide) resulted in novel compounds with anticonvulsant activities superior to that of either drug alone. Here, we examined the effects of six such chimeric compounds on Na(+)-channel function in central nervous system catecholaminergic (CAD) cells. Using whole-cell patch clamp electrophysiology, we demonstrated that these compounds affected Na(+) channel fast and slow inactivation processes.