Covalent chemistry coupled with activity-based protein profiling (ABPP) offers a versatile way to discover ligands for proteins in native biological systems. Here, we describe a set of stereo- and regiochemically defined spirocycle acrylamides and the analysis of these electrophilic "stereoprobes" in human cancer cells by cysteine-directed ABPP. Despite showing attenuated reactivity compared to structurally related azetidine acrylamide stereoprobes, the spirocycle acrylamides preferentially liganded specific cysteines on diverse protein classes.
View Article and Find Full Text PDFNeaumycin B is a femtomolar inhibitor of U87 human glioblastoma. Using a newly developed anti-diastereoselective ruthenium-catalyzed butadiene-mediated crotylation of primary alcohol proelectrophiles via hydrogen auto-transfer, as well as a novel variant of the catalytic asymmetric vinylogous Mukaiyama aldol (VMA) reaction applicable to linear aliphatic aldehydes and terminally methylated dienyl ketene acetals, preparation of the key C1-C19 and C23-C35 substructures of neaumycin B is achieved in 12 and 7 steps (LLS), respectively.
View Article and Find Full Text PDFThe mechanism of π-allyliridium -benzoate-catalyzed allylic amination was studied by reaction progress kinetic analysis (RPKA), tandem ESI-MS analysis, and computational studies involving density functional theory (DFT) calculations. Reaction progress kinetic analysis (RPKA) reveals a zero-order dependence on allyl acetate, first-order dependence on catalyst and fractional-order dependence on amine. These data corroborate rapid ionization of the allylic acetate followed by turnover limiting C-N bond formation.
View Article and Find Full Text PDFRobust air-stable cyclometalated π-allyliridium ,-benzoates modified by ()-tol-BINAP catalyze the reaction of secondary aliphatic amines with racemic alkyl-substituted allylic acetates to furnish products of allylic amination with high levels of enantioselectivity. Complete branched regioselectivities were observed despite the formation of more highly substituted C-N bonds.
View Article and Find Full Text PDFSince bromodomain containing 4 (brd4) has been considered as a prominent cancer target, numerous attempts have been made to develop potent brd4 bromodomain inhibitors. The present study provided a novel chemical scaffold which inhibited brd4 activity. Mid-throughput screening against brd4 bromodomain was performed using alpha-screen and homogeneous time-resolved fluorescence assays.
View Article and Find Full Text PDFEpigenetic regulation is known to play a key role in progression of anti-cancer therapeutics. Lysine acetylation is an important mechanism in controlling gene expression. There has been increasing interest in bromodomain owing to its ability to modulate transcription of various genes as an epigenetic 'reader.
View Article and Find Full Text PDFThe potent spliceosome modulator pladienolide B, which bears 10 stereogenic centers, is prepared in 10 steps (LLS). Asymmetric alcohol-mediated carbonyl crotylations catalyzed by ruthenium and iridium that occur with syn- and anti-diastereoselectivity, respectively, were used to form the C20-C21 and C10-C11 C-C bonds.
View Article and Find Full Text PDFHighly enantioselective catalytic reductive coupling of allyl acetate with acetylenic ketones occurs in a chemoselective manner in the presence of aliphatic or aromatic ketones. This method was used to construct C14-C23 of pladienolide D in half the steps previously required.
View Article and Find Full Text PDFBiochem Biophys Res Commun
September 2018
Bromodomain-containing protein 4 (Brd4) is known to play a key role in tumorigenesis. It binds acetylated histones to regulate the expression of numerous genes. Because of the importance of brd4 in tumorigenesis, much research has been undertaken to develop brd4 inhibitors with therapeutic potential.
View Article and Find Full Text PDFBioorg Med Chem Lett
December 2017
A series of 4-(phenoxymethyl)thiazole derivatives was synthesized and evaluated for their GPR119 agonistic effect. Several 4-(phenoxymethyl)thiazoles with pyrrolidine-2,5-dione moieties showed potent GPR119 agonistic activities. Among them, compound 27 and 32d showed good in vitro activity with an EC value of 49 nM and 18 nM, respectively with improved human and rat liver microsomal stability compare with MBX-2982.
View Article and Find Full Text PDFBromodomain-containing protein 4 (BRD4) is known to regulate the expression of c-Myc to control the proliferation of cancer cells. Therefore, development of small-molecule inhibitors targeting the bromodomain has been widely studied. However, some clinical trials on BRD4 inhibitors have shown its drawbacks such as toxicity including the loss of organ weight.
View Article and Find Full Text PDFProtein phosphatase 2A (PP2A) is a critical tumor suppressor complex responsible for the inactivation of various oncogenes. Recently, PP2A reactivation has emerged asan anticancer strategy. Cancerous inhibitor of protein phosphatase 2A (CIP2A), an endogenous inhibitor of PP2A, is upregulated in many cancer cells, including non-small cell lung cancer (NSCLC) cells.
View Article and Find Full Text PDF