Apilimod dimesylate in C9orf72 amyotrophic lateral sclerosis: a randomized phase 2a clinical trial.

Apilimod dimesylate is a first-in-class phosphoinositide kinase, FYVE-type zinc finger-containing (PIKfyve) inhibitor with a favourable clinical safety profile and has demonstrated activity in preclinical C9orf72 and TDP-43 amyotrophic lateral sclerosis (ALS) models. In this ALS clinical trial, the safety, tolerability, CNS penetrance and modulation of pharmacodynamic target engagement biomarkers were evaluated. This phase 2a, randomized, double-blind, placebo-controlled, biomarker-end-point clinical trial was conducted in four US centres (ClinicalTrials.gov NCT05163886). Participants with C9orf72 repeat expansions were randomly assigned (2:1) to receive twice-daily oral treatment with 125 mg apilimod dimesylate capsules or matching placebo for 12 weeks, followed by a 12-week open-label extension. Safety was measured as the occurrence of treatment-emergent or serious adverse events attributable to the study drug and tolerability at trial completion or treatment over 12 weeks. Changes from baseline in plasma and CSF and concentrations of apilimod dimesylate and its active metabolites and of pharmacodynamic biomarkers of PIKfyve inhibition [soluble glycoprotein nonmetastatic melanoma protein B (sGPNMB) upregulation] and disease-specific CNS target engagement [poly(GP)] were measured. Between 16 December 2021 and 7 July 2022, 15 eligible participants were enrolled. There were no drug-related serious adverse events reported in the trial. Fourteen (93%) participants completed the double-blind period with 99% dose compliance [n = 9 (90%) apilimod dimesylate; n = 5 (100%) placebo]. At Week 12, apilimod dimesylate was measurable in CSF at 1.63 ng/ml [standard deviation (SD): 0.937]. At Week 12, apilimod dimesylate increased plasma sGPNMB by >2.5-fold (P < 0.001), indicating PIKfyve inhibition, and lowered CSF poly(GP) protein levels by 73% (P < 0.001), indicating CNS tissue-level proof of mechanism. Apilimod dimesylate met prespecified key safety and biomarker end-points in this phase 2a trial and demonstrated CNS penetrance and pharmacodynamic target engagement. Apilimod dimesylate was observed to result in the greatest reduction in CSF poly(GP) levels observed to date in C9orf72 clinical trials.

A Noncoordinating Acid-Base Catalyst for the Mild and Nonreversible tert-Butylation of Alcohols and Phenols.

A mild and nonreversible tert-butylation of alcohols and phenols can be achieved in high yields using the noncoordinating acid-base catalyst [bis(trifluoromethane)sulfonimide and 2,6-lutidine] with a tert-butylation reagent, tert-butyl 2,2,2-trichloroacetimidate. This method allows the use of substrates containing acid sensitive groups such as ketal, Boc, and boronate esters.

Development of a 13C NMR Chemical Shift Prediction Procedure Using B3LYP/cc-pVDZ and Empirically Derived Systematic Error Correction Terms: A Computational Small Molecule Structure Elucidation Method.

An accurate and efficient procedure was developed for performing 13C NMR chemical shift calculations employing density functional theory with the gauge invariant atomic orbitals (DFT-GIAO). Benchmarking analysis was carried out, incorporating several density functionals and basis sets commonly used for prediction of 13C NMR chemical shifts, from which the B3LYP/cc-pVDZ level of theory was found to provide accurate results at low computational cost. Statistical analyses from a large data set of 13C NMR chemical shifts in DMSO are presented with TMS as the calculated reference and with empirical scaling parameters obtained from a linear regression analysis. Systematic errors were observed locally for key functional groups and carbon types, and correction factors were determined. The application of this process and associated correction factors enabled assignment of the correct structures of therapeutically relevant compounds in cases where experimental data yielded inconclusive or ambiguous results. Overall, the use of B3LYP/cc-pVDZ with linear scaling and correction terms affords a powerful and efficient tool for structure elucidation.

Systematic investigation of DFT-GIAO 15N NMR chemical shift prediction using B3LYP/cc-pVDZ: application to studies of regioisomers, tautomers, protonation states and N-oxides.

The calculation of 15N NMR chemical shifts has been systematically investigated using density functional theory-gauge including/invariant atomic orbitals (DFT-GIAO) approximation at the B3LYP/cc-pVDZ level of theory. General linear regression terms for 15N chemical shift predictions were calculated for nitromethane and liquid ammonia references in DMSO. Both aliphatic and aromatic nitrogens were studied using a diverse set of molecular scaffolds. Statistical error analysis between experiment and prediction revealed that, with the exception of primary amines, 95% of linear scaled N-15 chemical shifts are within a ±9.56 ppm range. Comparison of the 15N calculated isotropic chemical shifts with the experimentally determined chemical shifts provided accurate assignment of the correct structure in cases where experimental data was ambiguous or inconclusive. Application of 15N prediction proved to be highly effective in identifying the correct regio-isomer, oxidation state, protonation state and preferred tautomer in solution.

Sequential C-H Arylation and Enantioselective Hydrogenation Enables Ideal Asymmetric Entry to the Indenopiperidine Core of an 11ß-HSD-1 Inhibitor.

A concise asymmetric synthesis of an 11ß-HSD-1 inhibitor has been achieved using inexpensive starting materials with excellent step-economy at low catalyst loadings. The catalytic enantioselective total synthesis of 1 was accomplished in 7 steps and 38% overall yield aided by the development of an innovative, sequential strategy involving Pd-catalyzed pyridinium C-H arylation and Ir-catalyzed asymmetric hydrogenation of the resulting fused tricyclic indenopyridinium salt highlighted by the use of a unique P,N-ligand (MeO-BoQPhos) with 1000 ppm of [Ir(COD)Cl]2.

An Enantioselective Synthesis of an 11-ß-HSD-1 Inhibitor via an Asymmetric Methallylation Catalyzed by (S)-3,3'-F2-BINOL.

An efficient asymmetric synthesis of 11-ß-HSD inhibitor 1 has been accomplished in five linear steps and 53% overall yield, starting from the readily available 3-chloro-1-phenylpropan-1-one. The key feature of the synthesis includes an asymmetric methallylation of 3-chloro-1-phenylpropan-1-one catalyzed by the highly effective organocatalyst (S)-3,3'-F2-BINOL under solvent-free and metal-free conditions.

Transnitrilation from Dimethylmalononitrile to Aryl Grignard and Lithium Reagents: A Practical Method for Aryl Nitrile Synthesis.

An electrophilic cyanation of aryl Grignard or lithium reagents, generated in situ from the corresponding aryl bromides or iodides, by a transnitrilation with dimethylmalononitrile (DMMN) was developed. DMMN is a commercially available, bench-stable solid. The transnitrilation with DMMN avoids the use of toxic reagents and transition metals and occurs under mild reaction conditions, even for extremely sterically hindered substrates. The transnitrilation of aryllithium species generated by directed ortho-lithiation enabled a net C-H cyanation. The intermediacy of a Thorpe-type imine adduct in the reaction was supported by isolation of the corresponding ketone from the quenched reaction. Computational studies supported the energetic favorability of retro-Thorpe fragmentation of the imine adduct.

Development of an asymmetric synthesis of a chiral quaternary FLAP inhibitor.

A practical sequence involving a noncryogenic stereospecific boronate rearrangement followed by a robust formylation with an in situ generated DCM anion has been developed for the asymmetric construction of an all-carbon quaternary stereogenic center of a FLAP inhibitor. The key boronate rearrangement was rendered noncryogenic and robust by using LDA as the base and instituting an in situ trapping of the unstable lithiated benzylic carbamate with the boronic ester. A similar strategy was implemented for the DCM formylation reaction. It was found that the 1,2-boronate rearrangement for the formylation reaction could be temperature-controlled, thus preventing overaddition of the DCM anion and rendering the process reproducible. The robust stereospecific boronate rearrangement and formylation were utilized for the practical asymmetric synthesis of a chiral quaternary FLAP inhibitor.

Three-dimensional structure of cyclic antibiotic teicoplanin aglycone using NMR distance and dihedral angle restraints in a DMSO solvation model.

The three-dimensional solution conformation of teicoplanin aglycone was determined using NMR spectroscopy. A combination of NOE and dihedral angle restraints in a DMSO solvation model was used to calculate an ensemble of structures having a root mean square deviation of 0.17 Å. The structures were generated using systematic searches of conformational space for optimal satisfaction of distance and dihedral angle restraints. Comparison of the NMR-derived structure of teicoplanin aglycone with the X-ray structure of a teicoplanin aglycone analog revealed a common backbone conformation with deviation of two aromatic side chain substituents. Experimentally determined backbone (13)C chemical shifts showed good agreement with those computed at the density functional level of theory, providing a cross validation of the backbone conformation. The flexible portion of the molecule was consistent with the region that changes conformation to accommodate protein binding. The results showed that a hydrogen-bonded DMSO molecule in combination with NMR-derived restraints together enabled calculation of structures that satisfied experimental data.

Concise and Practical Asymmetric Synthesis of a Challenging Atropisomeric HIV Integrase Inhibitor.

A practical and efficient synthesis of a complex chiral atropisomeric HIV integrase inhibitor has been accomplished. The combination of a copper-catalyzed acylation along with the implementation of the BI-DIME ligands for a ligand-controlled Suzuki cross-coupling and an unprecedented bis(trifluoromethane)sulfonamide-catalyzed tert-butylation renders the synthesis of this complex molecule robust, safe, and economical. Furthermore, the overall synthesis was conducted in an asymmetric and diastereoselective fashion with respect to the imbedded atropisomer.

Efficient asymmetric synthesis of structurally diverse P-stereogenic phosphinamides for catalyst design.

The use of chiral phosphinamides is relatively unexplored because of the lack of a general method for the synthesis. Reported herein is the development of a general, efficient, and highly enantioselective method for the synthesis of structurally diverse P-stereogenic phosphinamides. The method relies on nucleophilic substitution of a chiral phosphinate derived from the versatile chiral phosphinyl transfer agent 1,3,2-benzoxazaphosphinine-2-oxide. These chiral phosphinamides were utilized for the first synthesis of readily tunable P-stereogenic Lewis base organocatalysts, which were used successfully for highly enantioselective catalysis.

A mild dihydrobenzooxaphosphole oxazoline/iridium catalytic system for asymmetric hydrogenation of unfunctionalized dialins.

Air-stable P-chiral dihydrobenzooxaphosphole oxazoline ligands were designed and synthesized. When they were used in the iridium-catalyzed asymmetric hydrogenation of unfunctionalized 1-aryl-3,4-dihydronaphthalenes under one atmosphere pressure of H2 , up to 99:1 e.r. was obtained. High enantioselectivities were also observed in the reduction of the exocyclic imine derivatives of 1-tetralones.

Remarkable enhancement of enantioselectivity in the asymmetric conjugate addition of dimethylzinc to (Z)-nitroalkenes with a catalytic [(MeCN)4Cu]PF6-Hoveyda ligand complex.

An enantioselective copper-catalyzed asymmetric conjugate addition of Me2Zn to (Z)-nitroalkenes led to the formation of all-carbon quaternary stereogenic centers with high stereoselectivity. The key features of the new method are the unprecedented use of [(MeCN)4Cu]PF6 in conjunction with the Hoveyda ligand L1 and the use of (Z)-nitroalkene substrates so that undesired nitroalkene isomerization is minimized and enantioselectivity is enhanced dramatically. We also describe a novel, practical, and highly (Z)-selective nitroalkene synthesis.

Carbamoyl anion addition to N-sulfinyl imines: highly diastereoselective synthesis of α-amino amides.

Carbamoyl anions, generated from N,N-disubstituted formamides and lithium diisopropylamide, add with high diastereoselectivity to chiral N-sulfinyl aldimines and ketimines to provide α-amino amides. The methodology enables the direct introduction of a carbonyl group without the requirement of unmasking steps as with other nucleophiles. The products may be converted to α-amino esters or 1,2-diamines. Iterative application of the reaction enabled the stereoselective synthesis of a dipeptide. Spectroscopic and computational studies support an anion structure with η(2) coordination of lithium by the carbonyl group.

Zinc catalyzed and mediated asymmetric propargylation of trifluoromethyl ketones with a propargyl boronate.

The development of zinc-mediated and -catalyzed asymmetric propargylations of trifluoromethyl ketones with a propargyl borolane and the N-isopropyl-l-proline ligand is presented. The methodology provided moderate to high stereoselectivity and was successfully applied on a multikilogram scale for the synthesis of the Glucocorticoid agonist BI 653048. A mechanism for the boron-zinc exchange with a propargyl borolane is proposed and supported by modeling at the density functional level of theory. A water acceleration effect on the zinc-catalyzed propargylation was discovered, which enabled a catalytic process to be achieved. Reaction progress analysis supports a predominately rate limiting exchange for the zinc-catalyzed propargylation. A catalytic amount of water is proposed to generate an intermediate that catalyzes the exchange, thereby facilitating the reaction with trifluoromethyl ketones.

Study of enantioselectivity on an immobilized amylose carbamate stationary phase under subcritical fluid chromatography.

In this paper, we describe the enantiomeric separation of a chiral alcohol under subcritical fluid chromatography conditions using a 3 µm particle size bonded amylose carbamate stationary phase. Linear and branched alcohols were used as polar modifiers in CO2. The studies with linear alcohols showed a decrease in selectivity factor as the number of carbons in the linear chain increased. For branched alcohols, as the bulk of substituents at the α carbon atom increases the separation factor decreases. Thermodynamic studies showed that in the presence of the alcohols studies, except methanol and ethanol, a positive ΔΔS was observed. Molecular mechanics simulation brought more insights into the mechanism of enantiomeric separation on this stationary phase under subcritical fluid chromatography.

A general copper-BINAP-catalyzed asymmetric propargylation of ketones with propargyl boronates.

An operationally simple copper-BINAP-catalyzed, highly enantioselective propargylation of ketones is presented. The methodology was developed as an enantioselective process for methyl ethyl ketone and shown to be applicable to a wide variety of prochiral ketones. The resulting homopropargyl adducts are versatile latent carbonyls from which γ-butyrolactones, ß-hydroxy methyl ketones, and ß-hydroxycarboxylates are readily obtained.

Copper catalyzed asymmetric propargylation of aldehydes.

The highly enantio- and regioselective copper catalyzed asymmetric propargylation of aldehydes with a propargyl borolane reagent is reported. The methodology demonstrated broad functional group tolerance and provided high enantioselectivities for aliphatic, vinyl, and aryl aldehydes. The utility of the TMS homopropargylic alcohols was demonstrated by the facile conversion to a chiral dihydropyranone.

2,5-Disubstituted tetrahydrofurans as selective serotonin re-uptake inhibitors.

Enhancement of 5-hydroxytryptamine (5-HT, serotonin) neurotransmission is a viable means of treating depression. On the basis of this observation, agents that inhibit re-uptake of 5-HT were prepared based on (-)-cocaine and aryltropanes as lead compounds because they are reasonably potent 5-HT re-uptake inhibitors. Molecular dissection of an aryltropane provided a series of 5- and 6-membered ring compounds. From among this library of compounds a series of disubstituted tetrahydrofurans bearing 2-alkyl aryl and 5-alkyl amino groups were identified as having highly potent and selective 5-HT re-uptake inhibition. The compounds were evaluated for their ability to compete with radiolabeled RTI-55 binding and to inhibit re-uptake of neurotransmitters at the human dopamine, serotonin and norepinephrine transporters. Based on potency (e.g., K(i)=800 pM) and significant functional selectivity (e.g., IC(50) ratios for human dopamine:serotonin or norepinephrine:serotonin, >or=1397) highly potent and selective serotonin re-uptake inhibitors were identified. Optimal features playing a dominant role in binding affinity and re-uptake inhibition included lipophilic substitution on the aromatic moiety, trans relative stereochemistry of the 2,5-disubstituted tetrahydrofuran ring, and a total of four or five methylene groups between the alkyl amine and the alkyl aryl moiety and the tetrahydrofuran group. A number of the most potent serotonin re-uptake inhibitors were tested in Balb/c mice in the forced-swim test (FST), a behavioral test used to measure the effects of antidepressant agents. Acute administration of 32c (10mg/kg), or 32d (10mg/kg) ip tended to decrease the duration of mouse immobility in the FST although the effect was not statistically significant.

Enantioselective Synthesis of α-(Hetero)aryl Piperidines through Asymmetric Hydrogenation of Pyridinium Salts and Its Mechanistic Insights.

Enantioselective synthesis of α-aryl and α-heteroaryl piperidines is reported. The key step is an iridium-catalyzed asymmetric hydrogenation of substituted N-benzylpyridinium salts. High levels of enantioselectivity up to 99.3:0.7 er were obtained for a range of α-heteroaryl piperidines. DFT calculations support an outersphere dissociative mechanism for the pyridinium reduction. Notably, initial protonation of the final enamine intermediate determines the stereochemical outcome of the transformation rather than hydride reduction of the resultant iminium intermediate.