Direct Deprotonative Functionalization of α,α-Difluoromethyl Ketones using a Catalytic Organosuperbase

The deprotonative functionalization of α,α-difluoromethyl ketones is described herein. Using a catalytic organosuperbase and a silane additive, the corresponding difluoroenolate could be generated and trapped with aldehydes to deliver various α,α-difluoro-β-hydroxy ketones in high yields. This new strategy tolerates numerous functional groups and represents the access to the difluoroenolate by direct deprotonation of the difluoromethyl unit. The diastereoselective version of the reaction was also investigated with d.r. up to 93 : 7. Several transformations were performed to demonstrate the synthetic potential of these α,α-difluoro-β-hydroxy ketones. In addition, this method has been extended to the use of other electrophiles such as imines and chalcogen derivatives, and a difluoromethyl sulfoxide as nucleophile, thus leading to a diversity of difluoromethylene compounds.

Efficacy and safety of abiraterone acetate plus prednisolone in patients with early metastatic castration-resistant prostate cancer who failed first-line androgen-deprivation therapy: a single-arm, phase 4 study

Aim

The aim was to evaluate the efficacy and safety of abiraterone acetate plus prednisolone in patients with chemotherapy-naïve early metastatic castration-resistant prostate cancer who failed first-line androgen deprivation therapy.

Methods

Patients with early metastatic castration-resistant prostate cancer with confirmed prostate-specific antigen progression within 1-year or prostate-specific antigen progression without having normal prostate-specific antigen level (<4.0 ng/mL) during first-line androgen deprivation therapy were enrolled and administered abiraterone acetate (1000 mg) plus prednisolone (10 mg). A minimum of 48 patients were required according to Simon’s minimax design. The primary endpoint was prostate-specific antigen response rate (≥50% prostate-specific antigen decline by 12 weeks), secondary endpoints included prostate-specific antigen progression-free survival and overall survival. Safety parameters were also assessed.

Results

For efficacy, 49/50 patients were evaluable. Median age was 73 (range: 55–86) years. The median duration of initial androgen deprivation therapy was 32.4 (range: 13.4–84.1) weeks and 48 patients experienced prostate-specific antigen progression within 1-year after initiation of androgen deprivation therapy. prostate-specific antigen response rate was 55.1% (95% confidence interval: 40.2%–69.3%), median prostate-specific antigen–progression-free survival was 24.1 weeks, and median overall survival was 102.9 weeks (95% confidence interval: 64.86 not estimable [NE]). Most common adverse event was nasopharyngitis (15/50 patients, 30.0%). The most common ≥grade 3 adverse event was alanine aminotransferase increased (6/50 patients, 12.0%).

Conclusions

Abiraterone acetate plus prednisolone demonstrated a high prostate-specific antigen response rate of 55.1%, suggesting tumor growth still depends on androgen synthesis in patients with early metastatic castration-resistant prostate cancer. However, prostate-specific antigen–progression-free survival was shorter than that reported in previous studies. Considering the benefit–risk profile, abiraterone acetate plus prednisolone would be a beneficial treatment option for patients with chemotherapy-naive metastatic prostate cancer who show early castration resistance.

Enantioselective Functionalization of Difluorocyclopropenes Catalyzed by Chiral Copper Complexes: Proposal for Chiral gem-Dimethyl and tert-Butyl Analogues

The highly enantioselective copper/chiral phosphine-catalyzed hydro-, bora-, and carbo-metalations of difluorocyclopropenes with PHMS [H-Si], H-BPin, (BPin)₂, and (CH₃)₂Zn [Zn-Me] are shown to regiodivergently afford highly enantioenriched and functionalized difluorocyclopropanes. These examples can be viewed as the first successful syntheses of "chiral" gem-dimethyl and tert-butyl analogues.

Citizens under the umbrella: citizenship projects and the development of genetic umbrella organizations in the USA and the UK

Social scientists have observed previously that patient support groups began to have significant influence over both research and clinical services of medical genetics in the early 2000s. This observation led to the idea of genetic citizenship, suggesting that the active participation and intervention of patient support groups in the rapidly growing field of medicine marked the emergence of a new form of citizenship. To understand how this citizenship emerged, this paper examines the development of umbrella organizations of genetic support groups in the USA and the UK. The historical analysis demonstrates that the ways in which these organizations developed differ considerably, and that their visions and activities reflected the different structural and cultural organizations of medical genetics in their respective countries. By recognizing the early work of these organizations as citizenship projects, this article argues that they helped rather different forms of genetic citizenship to emerge in the two countries.

Synthetic Methodologies for Perfluoroaryl-Substituted (Diaryl)methylphosphonates, -Phosphinates via SNAr Reaction

The new synthetic methodologies for perfluoroaryl-substituted (diaryl)methylphosphonates, -phosphinates via nucleophilic aromatic substitution (S_NAr) were developed. Benzylphosphonate and α-fluorobenzylphosphonate reacted with a wide variety of perfluoroarenes via S_NAr reaction. The reaction took place quickly and gave perfluoroarylated phosphonates in high yields. Highly diastereoselective S_NAr reaction with binaphthyl-based chiral phosphinates was further carried out.

Orphans in the Market: The History of Orphan Drug Policy

This paper examines the history of orphan drug policy, from the emergence of 'orphans' in the American pharmaceutical market in the 1960s, through the debates and agitations that resulted in the passage of the US Orphan Drug Act of 1983, to attempts in the 1990s to prevent abuse of that Act and restore its original intentions. Although an increased number of drugs for rare diseases have since been developed and marketed, the extremely high price of some such drugs is considered a major public health issue internationally. The present paper traces the origins of this issue to the market-based approach to resolving the problem of orphan drugs embodied in the 1983 Act. The paper also makes visible an alternative trajectory that existed for a while in the United Kingdom but was eventually abandoned in order to help the biotechnology industry grow in the context of an increasingly integrated European drug market.

gem-Digold Acetylide Complexes for Catalytic Intermolecular [4 + 2] Cycloaddition: Having Two Gold Centers Is Better for Asymmetric Catalysis

Gold(I)-catalyzed highly enantioselective intermolecular [4 + 2] cycloaddition is shown with ynones and cyclohexadiene. Various bicyclo[2.2.2]octadiene derivatives are produced in high yields (up to 99%) with good enantioselectivity (up to 96% ee). Key to the success is generation of the gem-digold terminal alkyne as a catalytic on-cycle species. As proof of the gem-digold catalysis, a positive nonlinear effect is clarified between the ee's of the ligand and the cycloadduct.

Asymmetric "Acetylenic" [3+2] Cycloaddition of Nitrones Catalyzed by Cationic Chiral PdII Lewis Acid

Highly enantioselective [3+2] cycloaddition of ynones and nitrones has been developed. Very bulky ligand, DTBM-SEGPHOS, was used for an effective asymmetric induction over distal reaction centers on the linear ynone dipolarophile and for prevention of Pd^II catalyst deactivation by coordination of the nitrones. The reaction has wide scope of substrates in both ynones and nitrones.

(Sila)Difluoromethylation of Fluorenyllithium with CF3H and CF3TMS

Difluoromethylation of the C9-H site of the fluorene ring using lithium base and fluoroform (CF3H), which is one of the most cost-effective difluoromethylating reagents, is attained to give difluoromethylated fluorenes with an all-carbon quaternary center. The Ruppert–Prakash reagent (CF3TMS) can also be applied to the present reaction system, providing siladifluoromethylated fluorenes that can be utilized for sequential carbon–carbon bond-forming reactions through activation of the silyl group.

Observation of a Metastable P-Heterocyclic Radical by Muonium Addition to a 1,3-Diphosphacyclobutane-2,4-diyl

A 1,3-diphosphacyclobutane-2,4-diyl contains a unique unsaturated cyclic unit, and the presence of radical-type centers have been expected as a source of functionality. This study demonstrates that the P-heterocyclic singlet biradical captures muonium (Mu=[μ⁺ e^- ]), the light isotope of a hydrogen radical, to generate an observable P-heterocyclic paramagnetic species. Investigation of a powder sample of 2,4-bis(2,4,6-tri-t-butylphenyl)-1-t-butyl-3-benzyl-1,3-diphosphacyclobutane-2,4-diyl using muon (avoided) level-crossing resonance (μLCR) spectroscopy revealed that muonium adds to the cyclic P₂ C₂ unit. The muon hyperfine coupling constant (A_μ ) indicated that the phosphorus atom bearing the t-butyl group trapped muonium to provide a metastable P-heterocyclic radical involving the ylidic MuP(<)=C moiety. The observed regioselective muonium addition correlates the canonical formula of 1,3-diphosphacyclobutane-2,4-diyl.

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

The catalytic asymmetric methylation of fluoroalkylated pyruvates is shown with dimethylzinc as a methylating reagent in the presence of a copper catalyst bearing a chiral phosphine ligand. This is the first catalytic asymmetric methylation to synthesize various α-fluoroalkylated tertiary alcohols with CF₃, CF₂H, CF₂Br, and n-C _n F_2n+1 (n = 2, 3, 8) groups in good-to-high yields and enantioselectivities. Axial backbones and substituents on phosphorus atoms of chiral phosphine ligands critically influence the enantioselectivity. Moreover, the methylation of simple perfluoroalkylated ketones is found to be facilitated by only chiral phosphines without copper.

CF3 -Inspired Synthesis of Air-Tolerant 9-Phosphaanthracenes that Feature Fluorescence and Crystalline Polymorphs

9-Phosphaanthracene (dibenzo[b,e]phosphorin, acridophosphine) has attracted interest as one of the heavier acenes. Herein, we demonstrate an efficient synthetic process that provides air-tolerant 1,8-bis(trifluoromethyl)-9-phosphaanthracenes. The sterically encumbered and electron-withdrawing trifluoromethyl (CF₃ ) groups are quite advantageous not only to stabilize the intrinsically unstable heavier unsaturated phosphorus atom but also to facilitate construction of the phosphinine skeleton based on a putative increase in aromaticity. The isolated 9-phosphaanthracenes allowed characterization of their fluorescence functionality and planar heteroanthracene frameworks. The crystal structures of 9-phosphaanthracenes are remarkably dependent on the aryl substituents at the 10 position; anthryl-substituted 9-phosphaanthracene showed unique polymorphs that induced different-colored crystals.

Patient organization involvement and the challenge of securing access to treatments for rare diseases: report of a policy engagement workshop

PLAIN ENGLISH SUMMARY

Patients with rare diseases often help to develop new treatments for their conditions. But once developed, those treatments are sometimes priced too high for many patients to access them. We became aware that this is a problem in the course of a social science research project that examines the place of rare diseases in health policy. We therefore organized a two-day workshop to try and understand why this problem occurs and what might be done about it. The people who participated in our workshop were: representatives of rare disease patient organizations, experts in matters of drug regulation and assessment of new health technologies, consultants involved with companies producing treatments for rare diseases, and social scientists researching related issues. The main conclusions to emerge from the discussions were as follows: Problems of access to treatments for rare diseases are not just due to high prices; procedures for regulating, assessing and delivering new treatments also need to be better organized. Patients and patient organizations have much to contribute to this process. However, their resources are often very limited. Consequently, more needs to be done to help them use those resources as effectively as possible. In particular, regulators and healthcare providers need to ensure that their procedures are clear and efficiently managed, so as not to waste patient organizations' time and money. Clearer guidance is needed on what patient organizations can do to provide evidence of the effectiveness of new drugs. Insights gained in tackling rare diseases might also be applicable to common disorders. Finally, the consequences of Brexit for UK policies on rare diseases urgently need to be assessed.

ABSTRACT

Since the enactment of orphan drug legislation in the USA, Europe and several other countries, an increasing number of treatments for rare diseases have been developed and many of them been approved for marketing. However, such treatments tend to be priced very high, and access to effective treatments remains a major challenge for patients with rare diseases - despite active involvement of patients and their support organizations in various stages of basic and applied research and commercial development. In order to allow patients to benefit from treatments proved effective for their diseases, we need to better understand why this challenge persists, and what steps might be taken to address it. To that end, we organized a policy-engagement workshop, bringing together individuals and organizations with direct experience of trying to secure access to a treatment for a rare disease along with individuals with relevant expertise in regulatory and commissioning processes for new medicines. With additional input from social scientists who offered different perspectives on the value of patient involvement, the workshop aimed to initiate a dialogue among the participants about how to address the challenge in a sustainable manner. Discussions at the workshop stressed that active involvement of patients is as valuable in the regulatory and commissioning processes as in the research and development of new medicines. However, it also highlighted certain risks and costs associated with such involvement. These include the costs of adjusting to abrupt changes in regulatory and commissioning processes, and the risk of being perceived as too close to commercial interests. To optimize use of scarce resources and ensure continuing active involvement, such risks and costs need to be better managed. Participants also noted that, owing to advances in genomic technologies, common diseases are also becoming divided into rare sub-categories, which are equally eligible for orphan drug designation. Consequently, involvement of wider patient communities beyond rare disease communities will be critical for continuing discussions about patients' involvement in regulatory and commissioning processes, and to consider how patients and their support organizations can best work with other stakeholders - including companies, regulators and policymakers - to ensure access to effective medicines.

Stable (sila)difluoromethylboranes via C–F activation of fluoroform derivatives

Lithium 1,3-bis(2,6-diisopropylphenyl)-2,3-dihydro-1H-1,3,2-diazaborol-2-uide activates the C–F linkage of CF₃R (R = H, SiMe₃) to provide difluoromethyl-substituted boranes as air-stable compounds.

Palladium-Catalyzed Negishi Cross-Coupling Reaction of Aryl Halides with (Difluoromethyl)zinc Reagent

The palladium-catalyzed Negishi cross-coupling reaction of aryl iodides and bromides with (difluoromethyl)zinc reagent bearing a diamine such as TMEDA is achieved to provide the difluoromethylated aromatic compounds in good to excellent yields. The advantages of (difluoromethyl)zinc reagent are that (1) the derivatives, which possess different stability and reactivity, can be readily prepared via ligand screening and (2) transmetalation of a difluoromethyl group from the zinc reagent to palladium catalyst efficiently proceeds without an activator.

Copper-Catalyzed Difluoromethylation of Aryl Iodides with (Difluoromethyl)zinc Reagent

The combination of difluoroiodomethane and zinc dust or diethylzinc can readily lead to (difluoromethyl)zinc reagents. Therefore, the first copper-catalyzed difluoromethylation of aryl iodides with the zinc reagents is accomplished to afford the difluoromethylated arenes. The reaction proceeds efficiently through the ligand/activator-free operation without addition of ligands for copper catalyst (e.g., phen and bpy) and activators for zinc reagent (e.g., KF, CsF, and NaO-t-Bu). Moreover, transmetalation of the CF2H group from zinc reagent to copper catalyst proceeds even at room temperature to form the cuprate [Cu(CF2H)2](-).

Perfluoroalkyl Grignard Reagents: NMR Study of 1-Heptafluoropropylmagnesium Chloride in Solution

We report on the generation of a perfluoroalkyl Grignard reagent ((F)RMgX) by exchange reaction between a perfluoroalkyl iodide ((F)R-I) and a Grignard reagent (RMgX). (19)F NMR was applied to monitor the generation of n-C3F7MgCl. Additional NMR techniques, including (19)F COSY, NOESY, and pulsed gradient spin-echo (PGSE) diffusion NMR, were invoked to assign peaks observed in (19)F spectrum. Schlenk equilibrium was observed and was significantly influenced by solvent, diethyl ether, or THF.

Siladifluoromethylation and Difluoromethylation onto C(sp(3)), C(sp(2)), and C(sp) Centers Using Ruppert-Prakash Reagent and Fluoroform

Siladifluoromethylations and difluoromethylations on sp(3), sp(2), and sp carbons of lithiated carbamates, arenes, and terminal alkynes, respectively, have been attained by employing the Ruppert-Prakash reagent (CF3TMS) and fluoroform (CF3H) as the CF2 sources. The advantage of this reaction is that the (sila)difluoromethylated compounds can be obtained by simple treatment of easily accessible substrates, lithium bases, and CF3TMS or CF3H. Furthermore, the products bearing the TMS group can be transformed into the valuable compounds with the CF2 fragment via the carbon-carbon bond forming reactions.

Access to Air-Stable 1,3-Diphosphacyclobutane-2,4-diyls by an Arylation Reaction with Arynes

Tuning of the physicochemical properties of the 1,3-diphosphacyclobutane-2,4-diyl unit is attractive in view of materials applications. The use of arynes is shown to be effective for installing relatively electron rich aryl substituents into the open-shell singlet P-heterocyclic system. Treatment of the sterically encumbered 1,3-diphosphacyclobuten-4-yl anion with ortho-silylated aryl triflates in the presence of fluoride under appropriate conditions afforded the corresponding 1-aryl 1,3-diphosphacyclobutane-2,4-diyls. The air-stable open-shell singlet P-heterocycles exhibit considerable electron-donating character, and the aromatic substituent influences the open-shell character, which is thought to be related to the property of p-type semiconductivity. The P-arylated 1,3-diphosphacyclobutane-2,4-diyl systems can be further utilized as detectors of hydrogen fluoride (HF), which causes a remarkable change in their photoabsorption properties.