One-Pot Synthesis of Ce-SSZ-39 Zeolite with Performance in the NH3-SCR Reaction.

Cu-SSZ-39 zeolite with 8-membered rings is regarded as a very promising catalyst in the NH3-SCR reaction, but its hydrothermal stability still remains to be improved. One of the solutions to promote hydrothermal stability is the insertion of rare earth elements in the product. Nevertheless, normal ion exchange of rare earth elements limits their contents in the zeolite product due to their large hydrated ionic radius and alkaline environment under hydrothermal conditions. Herein, we for the first time present a new method for the one-pot synthesis of Ce-SSZ-39 zeolite under solvent-free conditions. The key to success is the use of Ce-FAU zeolite as a precursor. The obtained product shows good crystallinity, sheet-like morphology, large BET surface area, and 4-coordinated Al species. Detailed investigations illustrate that Ce species in the Cu/Ce-SSZ-39 zeolite micropore can prevent the dealumination and thus formation of CuAlOx species during hydrothermal aging at 850 °C for 16 h, giving the excellent hydrothermal stability and thus showing the excellent catalytic performance in the NH3-SCR reaction. One-pot synthesis of Ce-SSZ-39 zeolite with excellent catalytic performance might open a new door for developing very efficient selective catalytic reduction (SCR) catalysts in near future.

Rational design, synthesis, and biological evaluation of Pan-Raf inhibitors to overcome resistance.

Selective BRafV600E inhibitors with DFG-in conformation have been proven effective against a subset of melanoma. However, representative inhibitor vemurafenib rapidly acquires resistance in the BRafWT cells through a CRaf or BRafWT dependent manner. Simultaneous targeting of all subtypes of Raf proteins offers the prospect of enhanced efficacy as well as reduced potential for acquired resistance. Herein, we describe the design and characterization of a series of compounds I-01-I-22, based on a pyrimidine scaffold with DFG-out conformation as Pan-Raf inhibitors. Among them, I-15 binds to all Raf protomers with IC50 values of 12.6 nM (BRafV600E), 30.1 nM (ARaf), 19.7 nM (BRafWT) and 17.5 nM (CRaf) and demonstrates cellular activity against BRafWT phenotypic melanoma and BRafV600E phenotypic colorectal cancer cells. The western blot results for the P-Erk inhibition in human melanoma SK-Mel-2 cell line showed that I-15 inhibited the proliferation of the SK-Mel-2 cell line at concentrations as low as 400 nM, without paradoxical activation of Erk as vemurafenib, which supported that I-15 may become a good candidate compound to overcome the resistance of melanoma induced by vemurafenib. I-15 also has a favorable pharmacokinetic profile in rats. Rational design, synthesis, SAR, lead selection and evaluation of the key compounds studied are described.

Potent Pan-Raf and Receptor Tyrosine Kinase Inhibitors Based on a Cyclopropyl Formamide Fragment Overcome Resistance.

While selective BRafV600E inhibitors have been proven effective clinically, acquired resistance rapidly develops through reactivation of the mitogen-activated protein kinase (MAPK) pathway. Simultaneous targeting of multiple nodes in the pathway offers the prospect of enhanced efficacy as well as reduced potential for acquired resistance. Replacement pyridine group of Y-1 by a cyclopropyl formamide group afforded I-01 as a novel multitargeted kinase inhibitor template. I-01 displayed enzyme potency against Pan-Raf and receptor tyrosine kinases (RTKs). Based on the binding mode of I-01, analogues I-02-I-18 were designed and synthesized. The most promising compound I-16 potently inhibits all subtypes of Rafs with IC50 values of 3.49 (BRafV600E), 8.86 (ARaf), 5.78 (BRafWT), and 1.65 nM (CRaf), respectively. I-16 not only exhibit comparable antiproliferative activities with positive control compounds against HepG2, SW579, MV4-11, and COLO205 cell lines, but also suppress the proliferation of melanoma SK-MEL-2 harboring overexpressed BRafWT with IC50 values of 0.93 µM. The Western blot results for the ERK inhibition in human melanoma SK-MEL-2 cell lines show that I-16 inhibits the proliferation of SK-MEL-2 cell lines without paradoxical activation of ERK, which support the hypothesis that the inhibition of Pan-Raf and RTKs might be a tractable strategy to overcome the resistance of melanoma induced by the therapy with the current selective BRafV600E inhibitors.

Discovery of coumarin derivatives as potent and selective cyclin-dependent kinase 9 (CDK9) inhibitors with high antitumour activity.

Specific inhibition of CDK9 is considered a promising strategy for developing effective anticancer therapeutics. However, most of the reported CDK9 inhibitors are still at an early stage of development and lack selectivity against other CDKs. Herein, we discovered coumarin derivative 30i as a potent CDK9 inhibitor with high selectivity (8300-fold over CDK7). Binding mode analysis illustrated that the substituent coumarin moiety is a critical group for CDK9 selectivity by occupying a flexible hinge/αD region, which is sterically hindered in other CDKs. Compound 30i showed excellent cellular antiproliferative activity, moderate pharmacokinetic property and low hERG inhibition. Moreover, 30i significantly induced tumour growth inhibition in a dose-dependent manner without causing an obvious loss of body weight in an MV4-11 xenograft mice model. Altogether, these results suggest that 30i may serve as a potential acute myeloid leukaemia (AML) therapeutics by selectively targeting CDK9.

Discovery of potent Pan-Raf inhibitors with increased solubility to overcome drug resistance.

Despite various applications of kinase inhibitors in oncology and inflammatory diseases, the emergence of resistance still remains the major barrier to achieve long-term remission in cancer treatment. With the aim of overcoming the resistance induced by type IIB BRaf V600E selective inhibitor vemurafenib, and further ameliorating the antiproliferative activity, a novel type IIA Pan-Raf inhibitors Ia-Io based on pyrrolo[2,3-d] pyrimidine scaffold were designed and evaluated in this work. Herein, we tried to improve the cellular potency of the target compounds by increasing their solubility. Among them, Il, with the solubility of 0.107 mg/mL, demonstrated favorable cellular activity against vemurafenib-resistant carcinoma cells including BRafWT phenotypic melanoma SK-MEL-2 and BRafV600E phenotypic colorectal cancer HT-29 cell lines. Based on the well solubility, Il exhibited good metabolic stability compared to sorafenib and showed favorable pharmacokinetic profiles in rats. As for the biological mechanism research, Il had the similar P-ERK kinase inhibitory activity in A375 and SK-Mel-2 cells as our previously lead P-2. Il may become a good candidate compound to overcome the resistance associated with vemurafenib.

Design, synthesis and evaluation of derivatives based on pyrimidine scaffold as potent Pan-Raf inhibitors to overcome resistance.

Simutaneous targeting all Raf isoforms offers the prospect of enhanced efficacy as well as reduced potential for resistance. Described herein is the discovery and characterization of a series of pyrimidine scaffold with DFG-out conformation as potent Pan-Raf inhibitors. Among them, I-41 with excellent Pan-Raf potency demonstrates inhibitory activity against BRafWT phenotypic melanoma and BRafV600E phenotypic colon cells. The western blot results for the Erk inhibition in human melanoma SK-Mel-2 cell lines showed I-41 inhibited the proliferation of SK-Mel-2 cell lines without paradoxical activation of Erk, which supported I-41 may become a good candidate compound to overcome the resistance of melanoma against the current BRafV600E inhibitor therapy. I-41 also have a favorable pharmacokinetic profile in rat. Synthesis, SAR, lead selection, and evaluation of the key compounds studies are described.