While epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have changed the treatment landscape for EGFR mutant (L858R and ex19del)-driven non-small-cell lung cancer (NSCLC), most patients will eventually develop resistance to TKIs. In the case of first- and second-generation TKIs, up to 60% of patients will develop an EGFR T790M mutation, while third-generation irreversible TKIs, like osimertinib, lead to C797S as the primary on-target resistance mutation. The development of reversible inhibitors of these resistance mutants is often hampered by poor selectivity against wild-type EGFR, resulting in potentially dose-limiting toxicities and a sub-optimal profile for use in combinations.
View Article and Find Full Text PDFThe receptor tyrosine kinase rearranged during transfection (RET) is an oncogenic driver activated in multiple cancers, including non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC), and papillary thyroid cancer. No approved therapies have been designed to target RET; treatment has been limited to multikinase inhibitors (MKI), which can have significant off-target toxicities and limited efficacy. BLU-667 is a highly potent and selective RET inhibitor designed to overcome these limitations.
View Article and Find Full Text PDFBioorg Med Chem Lett
June 2017
Interleukin-1 receptor associated kinase 4 (IRAK4) has been implicated in IL-1R and TLR based signaling. Therefore selective inhibition of the kinase activity of this protein represents an attractive target for the treatment of inflammatory diseases. Medicinal chemistry optimization of high throughput screening (HTS) hits with the help of structure based drug design led to the identification of orally-bioavailable quinazoline based IRAK4 inhibitors with excellent pharmacokinetic profile and kinase selectivity.
View Article and Find Full Text PDFIRAK4 plays a critical role in the IL-1R and TLR signalling, and selective inhibition of the kinase activity of the protein represents an attractive target for the treatment of inflammatory diseases. A series of permeable N-(1H-pyrazol-4-yl)carboxamides was developed by introducing lipophilic bicyclic cores in place of the polar pyrazolopyrimidine core of 5-amino-N-(1H-pyrazol-4-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamides. Replacement of the pyrazolo[1,5-a]pyrimidine core with the pyrrolo[2,1-f][1,2,4]triazine, the pyrrolo[1,2-b]pyridazine, and thieno[2,3-b]pyrazine cores guided by cLogD led to the identification of highly permeable IRAK4 inhibitors with excellent potency and kinase selectivity.
View Article and Find Full Text PDFInterleukin-1 receptor associated kinase 4 (IRAK4) is an essential signal transducer downstream of the IL-1R and TLR superfamily, and selective inhibition of the kinase activity of the protein represents an attractive target for the treatment of inflammatory diseases. A series of 5-amino-N-(1H-pyrazol-4-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamides was developed via sequential modifications to the 5-position of the pyrazolopyrimidine ring and the 3-position of the pyrazole ring. Replacement of substituents responsible for poor permeability and improvement of physical properties guided by cLogD led to the identification of IRAK4 inhibitors with excellent potency, kinase selectivity, and pharmacokinetic properties suitable for oral dosing.
View Article and Find Full Text PDFThe oxetane ring is useful in drug discovery as a bioisostere for both the geminal dimethyl group and the carbonyl group. A convenient, straightforward approach to access structurally diverse 3-aminooxetanes through the reactivity of oxetan-3-tert-butylsulfinimine and the corresponding sulfinylaziridine is described.
View Article and Find Full Text PDFTetracyclines and tetracycline analogues are prepared by a convergent, single-step Michael-Claisen condensation of AB precursor 1 or 2 with D-ring precursors of wide structural variability, followed by removal of protective groups (typically in two steps). A number of procedural variants of the key C-ring-forming reaction are illustrated in multiple examples. These include stepwise deprotonation of a D-ring precursor followed by addition of 1 or 2, in situ deprotonation of a D-ring precursor in mixture with 1 or 2, and in situ lithium-halogen exchange of a benzylic bromide D-ring precursor in the presence of 1 or 2, followed by warming.
View Article and Find Full Text PDFAn operationally convenient, one-pot, three-step sequence has been developed that provides access to 3-substituted 4-, 5-, 6-, and 7-azaindolines (2,3-dihydro-1H-pyrollopyridines) via intramolecular carbolithiation of the aryllithium derived from an appropriate (N,N-diallylamino)bromopyridine. Whereas cyclization proceeds as expected to give 1-allyl-3-methyl-4-azaindoline and 1-allyl-3-methyl-6-azaindoline following protonation of the 3-CH2Li group of the azaindoline, the isomeric 3-methyl-5-azaindoline and 3-methyl-7-azaindoline are generated as 3-methyl-N-allyl anions prior to quench with MeOH.
View Article and Find Full Text PDFA practical, enantioselective synthetic route to a key precursor to the tetracycline antibiotics is reported. The route proceeds in nine steps (21% yield) from the commercial substance methyl 3-hydroxy-5-isoxazolecarboxylate. Key steps in the route involve enantioselective addition of divinylzinc to 3-benzyloxy-5-isoxazolecarboxaldehyde and an endo-selective intramolecular furan Diels-Alder cycloaddition reaction.
View Article and Find Full Text PDFComplex antibiotics based on natural products are almost invariably prepared by semisynthesis, or chemical transformation of the isolated natural products. This approach greatly limits the range of accessible structures that might be studied as new antibiotic candidates. Here we report a short and enantioselective synthetic route to a diverse range of 6-deoxytetracycline antibiotics.
View Article and Find Full Text PDFA general approach to preparing 1,5-methano- (1) and 1,5-ethano-2,3,4,5-tetrahydro-1H-3-benzazepine (2) is discussed. This strategy involves converting an indanone or tetralone (4) to a cyanohydrin (3) which is subjected to hydrogenolysis followed by lactamization and reduction to provide bicyclic aryl piperidine (1) and bicyclic aryl homopiperidine (2).
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