Synthesis of fluorescent heterocycles via a Knoevenagel/[4 + 1]-cycloaddition cascade using acetyl cyanide.

A concise one-pot three-component reaction that affords fluorescent indolizines, benzo[d]pyrrolo[2,1-b]thiazoles, and pyrrolo[1,2-a]pyrazines is reported. The methodology involves the formation of a heterocyclic 1-aza-1,3-diene derived from a Knoevenagel condensation between an aldehyde and 2-methyl-ene-cyano aza-heterocycles, followed by [4 + 1] cycloaddition of acetyl cyanide behaving as a non-classical isocyanide replacement.

One-Pot Two-Step Multicomponent Process of Indole and Other Nitrogenous Heterocycles or Amines toward α-Oxo-acetamidines.

A cesium carbonate promoted three-component reaction of N-H containing heterocycles, primary or secondary amines, arylglyoxaldehydes, and anilines is reported. The key step involves a tandem sequence of N-1 addition of a heterocycle or an amine to preformed α-iminoketones, followed by an air- or oxygen-mediated oxidation to form α-oxo-acetamidines. The scope of the reaction is enticingly broad, and this novel methodology is applied toward the synthesis of various polycyclic heterocycles.

Recent advances in allosteric androgen receptor inhibitors for the potential treatment of castration-resistant prostate cancer.

Prostate cancer (PC) is the second most frequent cause of male cancer death in the USA. As such, the androgen receptor (AR) plays a crucial role in PC, making AR the major therapeutic target for PC. Current antiandrogen chemotherapy prevents androgen binding to the ligand-binding pocket (LBP) of AR. However, PC frequently recurs despite treatment and it progresses to castration-resistant prostate cancer. Behind this regression is renewed AR signaling initiated via mutations in the LBP. Hence, there is a critical need to improve the therapeutic options to regulate AR activity in sites other than the LBP. Herein, recently disclosed (2010-2015) allosteric AR inhibitors are summarized and a perspective on the potential pharmaceutical intervention at these sites is provided.

The Synthesis of Stable, Complex Organocesium Tetramic Acids through the Ugi Reaction and Cesium-Carbonate-Promoted Cascades.

Two structurally unique organocesium carbanionic tetramic acids have been synthesized through expeditious and novel cascade reactions of strategically functionalized Ugi skeletons delivering products with two points of potential diversification. This is the first report of the use of multicomponent reactions and subsequent cascades to access complex, unprecedented organocesium architectures. Moreover, this article also highlights the first use of mild cesium carbonate as a cesium source for the construction of cesium organometallic scaffolds. Relativistic DFT calculations provide an insight into the electronic structure of the reported compounds.

(Z)-Stereoselective Synthesis of Mono- and Bis-heterocyclic Benzimidazol-2-ones via Cascade Processes Coupled with the Ugi Multicomponent Reaction.

Several novel cascade reactions are herein reported that enable access to a variety of unique mono- and bis-heterocyclic scaffolds. The sequence of cascade events are mediated through acid treatment of an Ugi adduct that affords 1,5-benzodiazepines which subsequently undergo an elegant rearrangement to deliver (E)-benzimidazolones, which through acid-promoted tautomerization convert to their corresponding (Z)-isomers. Moreover, a variety of heterocycles tethered to (Z)-benzimidazole-2-ones are also accessible through similar domino-like processes, demonstrating a general strategy to access significantly new scaffold diversity, each containing four points of potential diversification. Final structures of five scaffolds have been definitively proven by X-ray crystallography.

Zeta Inhibitory Peptide Disrupts Electrostatic Interactions That Maintain Atypical Protein Kinase C in Its Active Conformation on the Scaffold p62.

Atypical protein kinase C (aPKC) enzymes signal on protein scaffolds, yet how they are maintained in an active conformation on scaffolds is unclear. A myristoylated peptide based on the autoinhibitory pseudosubstrate fragment of the atypical PKCζ, zeta inhibitory peptide (ZIP), has been extensively used to inhibit aPKC activity; however, we have previously shown that ZIP does not inhibit the catalytic activity of aPKC isozymes in cells (Wu-Zhang, A. X., Schramm, C. L., Nabavi, S., Malinow, R., and Newton, A. C. (2012) J. Biol. Chem. 287, 12879-12885). Here we sought to identify a bona fide target of ZIP and, in so doing, unveiled a novel mechanism by which aPKCs are maintained in an active conformation on a protein scaffold. Specifically, we used protein-protein interaction network analysis, structural modeling, and protein-protein docking to predict that ZIP binds an acidic surface on the Phox and Bem1 (PB1) domain of p62, an interaction validated by peptide array analysis. Using a genetically encoded reporter for PKC activity fused to the p62 scaffold, we show that ZIP inhibits the activity of wild-type aPKC, but not a construct lacking the pseudosubstrate. These data support a model in which the pseudosubstrate of aPKCs is tethered to the acidic surface on p62, locking aPKC in an open, signaling-competent conformation. ZIP competes for binding to the acidic surface, resulting in displacement of the pseudosubstrate of aPKC and re-engagement in the substrate-binding cavity. This study not only identifies a cellular target for ZIP, but also unveils a novel mechanism by which scaffolded aPKC is maintained in an active conformation.

Crystal structures of N-tert-butyl-3-(4-fluoro-phenyl)-5-oxo-4-[2-(tri-fluoro-meth-oxy)phen-yl]-2,5-di-hydro-furan-2-carboxamide and 4-(2H-1,3-benzodioxol-5-yl)-N-cyclo-hexyl-5-oxo-3-[4-(tri-fluoro-meth-yl)phen-yl]-2,5-di-hydro-furan-2-carboxamide.

The title compounds, C22H19F4NO4, (I), and C25H22F3NO5, (II), each contain a central nearly planar di-hydro-furan-one ring. The r.m.s. deviation from planarity of these rings is 0.015 Šin (I) and 0.027 Šin (II). The mol-ecules are T-shaped, with the major conformational difference being the O-C-C-O torsion angle [-178.9 (1) in (I) and 37.7 (2)° in (II)]. In the crystal of (I), mol-ecules are linked by N-H⋯O hydrogen bonds, forming chains along [001] while in (II) mol-ecules are linked by N-H⋯O hydrogen bonds, forming chains along [010]. In (II), the tri-fluoro-methyl substituent is disordered over two sets of sites, with refined occupancies of 0.751 (3) and 0.249 (3).

Synthesis of diverse nitrogen-enriched heterocyclic scaffolds using a suite of tunable one-pot multicomponent reactions.

Five elegant and switchable three-component reactions which enable access to a new series of nitrogen-containing heterocycles are reported. A novel one-step addition of an isocyanide to a hydrazine derived Schiff base affords unique six-membered pyridotriazine scaffolds (A and E). With slight modification of reaction conditions and replacement of the nucleophilic isocyanide moiety with different electrophiles (i.e., isocyanates, isothiocyanates, cyclic anhydrides, and acyl chlorides) five-membered triazolopyridine scaffolds (B, D, F, G) are generated in a single step. Furthermore, the use of phenyl hydrazine enables access to dihydroindazole-carboxamides, devoid of a bridge-head nitrogen (C). All protocols are robust and tolerate a diverse collection of reactants, and as such, it is expected that the new scaffolds and associated chemistry will garner high interest from medicinal chemists involved in either file enhancement or specific target-related drug discovery campaigns.

A simple one-pot 2-step N-1-alkylation of indoles with α-iminoketones toward the expeditious 3-step synthesis of N-1-quinoxaline-indoles.

A straightforward procedure for the preparation of N-quinoxaline-indoles is presented. A base-catalyzed one-pot addition of indoles to a preformed α-iminoketone proceeds on the N-1 indole and the subsequent adduct undergoes an acid-mediated deprotection of an internal amino nucleophile, intramolecular cyclization and final oxidation generating N-1-quinoxaline-indoles in good yield.

2,4-Diphenyl-6-trifluoro-methyl-2,3-dihydro-1H,5H-pyrrolo-[3,4-c]pyrrole-1,3-dione.

The asymmetric unit of the title compound, C(19)H(11)F(3)N(2)O(2), contains two crystallographically unique mol-ecules which differ in the rotation of a phenyl ring and a -CF(3) substituent. The dihedral angles involving the pyrrole ring and the attached phenyl ring are 62.82 (8) and 71.54 (7)° in the two molecules. The difference in the rotation of the CF(3) groups with respect to the pyrrolo rings to which they are attached is 23.5(1)°. For one mol-ecule, there is a close contact between an H atom and the centroid of the phenyl ring of an adjacent mol-ecule (2.572 Å). A similar contact is lacking in the second mol-ecule. In the crystal, N-H⋯O inter-actions connect adjacent mol-ecules into a chain normal to (01[Formula: see text]). Crystallographically unique mol-ecules alternate along the hydrogen-bonded chains.