The Many Roles for Fluorine in Medicinal Chemistry

Purpose
The LUX-Lung 3 study investigated the efficacy of chemotherapy compared with afatinib, a selective, orally bioavailable ErbB family blocker that irreversibly blocks signaling from epidermal growth factor receptor (EGFR/ErbB1), human epidermal growth factor receptor 2 (HER2/ErbB2), and ErbB4 and has wide-spectrum preclinical activity against EGFR mutations. A phase II study of afatinib in EGFR mutation-positive lung adenocarcinoma demonstrated high response rates and progression-free survival (PFS).

Patients and Methods
In this phase III study, eligible patients with stage IIIB/IV lung adenocarcinoma were screened for EGFR mutations. Mutation-positive patients were stratified by mutation type (exon 19 deletion, L858R, or other) and race (Asian or non-Asian) before two-to-one random assignment to 40 mg afatinib per day or up to six cycles of cisplatin plus pemetrexed chemotherapy at standard doses every 21 days. The primary end point was PFS by independent review. Secondary end points included tumor response, overall survival, adverse events, and patient-reported outcomes (PROs).

Results
A total of 1,269 patients were screened, and 345 were randomly assigned to treatment. Median PFS was 11.1 months for afatinib and 6.9 months for chemotherapy (hazard ratio [HR], 0.58; 95% CI, 0.43 to 0.78; P = .001). Median PFS among those with exon 19 deletions and L858R EGFR mutations (n = 308) was 13.6 months for afatinib and 6.9 months for chemotherapy (HR, 0.47; 95% CI, 0.34 to 0.65; P = .001). The most common treatmentrelated adverse events were diarrhea, rash/acne, and stomatitis for afatinib and nausea, fatigue, and decreased appetite for chemotherapy. PROs favored afatinib, with better control of cough, dyspnea, and pain.

Conclusion
Afatinib is associated with prolongation of PFS when compared with standard doublet chemotherapy in patients with advanced lung adenocarcinoma and EGFR mutations.

Phase III study of afatinib or cisplatin plus pemetrexed in patients with metastatic lung adenocarcinoma with EGFR mutations

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

Applications of Palladium-Catalyzed C–N Cross-Coupling Reactions

Screening for Epidermal Growth Factor Receptor Mutations in Lung Cancer

The nature and characteristics of the CH/π interaction are discussed by comparison with other weak molecular forces such as the CH/O and OH/π interaction. The CH/π interaction is a kind of hydrogen bond operating between a soft acid CH and a soft base π-system (double and triple bonds, C6 and C5 aromatic rings, heteroaromatics, convex surfaces of fullerenes and nanotubes). The consequences of CH/π hydrogen bonds in supramolecular chemistry are reviewed on grounds of recent crystallographic findings and database analyses. The topics include intramolecular interactions, crystal packing (organic and organometallic compounds), host/guest complexes (cavity-type inclusion compounds of cyclodextrins and synthetic macrocyclic hosts such as calixarenes, catenanes, rotaxanes and pseudorotaxanes), lattice-inclusion type clathrates (including liquid crystals, porphyrin derivatives, cyclopentadienyl compounds and C60 fullerenes), enantioselective clathrate formation, catalytic enantioface discriminating reactions and solid-state photoreaction. The implications of the CH/π concept for crystal engineering and drug design are evident.

CH/π hydrogen bonds in crystals

Pharmacological blockade or genetic deletion of substance P (NK1) receptors attenuates neonatal vocalisation in guinea-pigs and mice

Chemical Double-Mutant Cycles for the Measurement of Weak Intermolecular Interactions: Edge-to-Face Aromatic Interactions†

We have synthesized a potent, selective, radioiodinated antagonist of the human neurokinin-1 (NK1) receptor and have characterized its binding to the cloned receptor expressed in Chinese hamster ovary cells. (cis)-2-(Diphenylmethyl)-N-[(2-iodophenyl)-methyl]-1- azabicyclo[2.2.2]octan-3-amine (L-703606) inhibits binding of 125I-Tyr8-substance P to the human NK1 receptor with an IC50 of 2 nM. This compound is a competitive antagonist of substance P-induced inositol phosphate generation, with a Kb of 29 nM. [125I]L-703606 binds to a single class of high affinity binding sites in human NK1/Chinese hamster ovary cell membranes (Kd = 0.3 nM). Substance P inhibits the binding of [125I]L-703606 to 65% of the NK1 receptor sites with a Kd of 0.04 +/- 0.03 nM and to the remaining 35% of the sites with a Kd of 1.5 +/- 0.7 nM. Addition of the nonhydrolyzable GTP analog guanylyl-5'-(beta, gamma-imido)diphosphate [Gpp(NH)p] shifts greater than 90% of the binding sites to the lower affinity state. In addition, Gpp(NH)p markedly alters the dissociation of substance P from the NK1 receptor by increasing the number of sites in the low affinity, rapidly dissociating state. However, Gpp(NH)p does not affect the rate of dissociation of [125I]L-703606. These data suggest that the pharmacological properties of [125I]L-703606 binding to the human NK1 receptor are similar to those of antagonists of nonpeptide guanine nucleotide-binding protein-coupled receptors and that this ligand will be useful for the biochemical and pharmacological characterization of the human NK1 receptor.

Characterization of the binding of a potent, selective, radioiodinated antagonist to the human neurokinin-1 receptor.

The present invention relates to compounds of formula (I), wherein R1 is hydrogen, halogen, C?1-6? alkyl, C?1-6? alkoxy, CF3, NO2, CN, SR?a, SORa, SO?2Ra, CO2R?a, CONRaRb, C?2-6 alkenyl, C2-6 alkynyl or C1-4 alkyl substituted by C1-4 alkoxy, where R?a and Rb? are hydrogen or C?1-4? alkyl; R?2? is hydrogen, halogen, C?1-6? alkyl, C1-6 alkoxy substituted by C1-4 alkoxy or CF3; R?3? is hydrogen, halogen or CF?3; R?4 is selected from the definitions of R1; R5 is selected from the definitions of R2; R6 is a 5-membered or 6-membered heterocyclic ring containing 2 or 3 nitrogen atoms optionally substituted by =O, =S or a C?1-4? alkyl group, and optionally substituted by an aminoalkyl group; R?9a and R9b? are hydrogen or C?1-4? alkyl, or R?9a and R9b? are joined to form a C?5-7? ring; X is C1-4 alkylene optionally substituted by oxo; and Y is a C1-4 alkyl group optionally substituted by hydroxyl; with the proviso that if Y is C1-4 alkyl, R?6? is substituted at least by an aminoalkyl group; and pharmaceutically acceptable salts and prodrugs thereof The compounds are of particular use in the treatment of pain, inflammation, migraine and emesis

Substituted morpholine derivatives and their use as therapeutic agents

Chemical double mutant cycles have been used to measure the magnitude of edge-to-face aromatic interactions in hydrogen-bonded zipper complexes as a function of substituents on both aromatic rings. The interaction energies vary depending on the combination of substituents from +1.0 kJ mol−1 (repulsive), to −4.9 kJ mol−1 (attractive). The results correlate with the Hammett substituent constants which indicates that electrostatic interactions are responsible for the observed differences in interaction energy. The experiments can be rationalised based on local electrostatic interactions between the protons on the edge ring and the π-electron density on the face ring as well as global electrostatic interactions between the overall dipoles on the two aromatic groups.

Eileen Mary Seward

Papers

Pharmacological blockade or genetic deletion of substance P (NK1) receptors attenuates neonatal vocalisation in guinea-pigs and mice

Chemical Double-Mutant Cycles for the Measurement of Weak Intermolecular Interactions: Edge-to-Face Aromatic Interactions†

Characterization of the binding of a potent, selective, radioiodinated antagonist to the human neurokinin-1 receptor.

Substituted morpholine derivatives and their use as therapeutic agents

Substituent Effects on Edge‐to‐Face Aromatic Interactions