Aza-Riley Oxidation of Ugi-Azide and Ugi-3CR Products toward Vicinal Tricarbonyl Amides: Two-Step MCR-Oxidation Methodology Accessing Functionalized α,ß-Diketoamides and α,ß-Diketotetrazoles.

Direct oxidative deamination of glyoxal-derived Ugi-azide and Ugi three-component reaction products readily affords vicinal tricarbonyls (α,ß-diketoamides) and α,ß-diketotetrazoles with two diversity elements. This significant extension of our previously described multicomponent reaction-oxidative deamination methodology is proposed to proceed through a mechanistically distinct SeO2-mediated C-N oxidation derived from an active enol of α-amino-ß-ketone systems, effectively an aza-Riley oxidation. This methodology accesses diverse VTC systems from prototypical amines, glyoxaldehydes, and isocyanide building blocks in a mere two steps.

Dyrk1 inhibition improves Alzheimer's disease-like pathology.

There is an urgent need for the development of new therapeutic strategies for Alzheimer's disease (AD). The dual-specificity tyrosine phosphorylation-regulated kinase-1A (Dyrk1a) is a protein kinase that phosphorylates the amyloid precursor protein (APP) and tau and thus represents a link between two key proteins involved in AD pathogenesis. Furthermore, Dyrk1a is upregulated in postmortem human brains, and high levels of Dyrk1a are associated with mental retardation. Here, we sought to determine the effects of Dyrk1 inhibition on AD-like pathology developed by 3xTg-AD mice, a widely used animal model of AD. We dosed 10-month-old 3xTg-AD and nontransgenic (NonTg) mice with a Dyrk1 inhibitor (Dyrk1-inh) or vehicle for eight weeks. During the last three weeks of treatment, we tested the mice in a battery of behavioral tests. The brains were then analyzed for the pathological markers of AD. We found that chronic Dyrk1 inhibition reversed cognitive deficits in 3xTg-AD mice. These effects were associated with a reduction in amyloid-ß (Aß) and tau pathology. Mechanistically, Dyrk1 inhibition reduced APP and insoluble tau phosphorylation. The reduction in APP phosphorylation increased its turnover and decreased Aß levels. These results suggest that targeting Dyrk1 could represent a new viable therapeutic approach for AD.

Copper(i) catalyzed oxidative hydrolysis of Ugi 3-component and Ugi-azide reaction products towards 2° α-ketoamides and α-ketotetrazoles.

Herein, a two-step MCR-oxidation methodology accessing decorated 2° α-ketoamides and α-ketotetrazoles is described via a catalytic copper(i)-mediated C-N oxidation/acidic hydrolysis of Ugi-three-component and Ugi-azide reaction products. The ability to install diversity from aldehyde and isocyanide synthons allows rapid complexity generation. Of note, (1) 2° α-ketoamides are traditionally difficult to access and more so reminiscent of the endogenous peptide bonds. (2) The route to α-keto-tetrazoles is significantly shorter than that in previous reports.

Oxidative Deaminations and Deisatinylations of Ugi-Azide and Ugi-3CR Products: A Two-Step MCR-Oxidation Protocol toward Functionalized α-Ketoamides and α-Ketotetrazoles.

A new postcondensation multicomponent reaction (MCR) methodology, comprising oxidative deaminations enabling access to multiple privileged carbonyl-containing scaffolds in two steps, is described. These protocols allow facile access to functionalized α-ketoamide and α-ketotetrazole small-molecule peptidomimetic-like building blocks from prototypical synthons with two points of diversity. Incorporation of chalcone and alkynyl moieties with further ring-forming reactions enables access to additional novel heterocyclic ring systems, including a unique and potentially highly pharmacologically relevant scaffold, a 1,2-selenazol-3(2H)-one.

Two-Step Route to Diverse N-Functionalized Peptidomimetic-like Isatins through an Oxidation/Intramolecular Oxidative-Amidation Cascade of Ugi Azide and Ugi Three-Component Reaction Products.

Two-step methodology described herein showcases the first example of an oxidation/oxidative amidation cyclization cascade of MCR products toward diverse N-functionalized isatins. Products of both the Ugi 3CR and the Ugi azide reactions are oxidatively cyclized through a postcondensation process utilizing selenium dioxide. This methodology was found to be applicable for the generation of bis-peptidomimetic-like isatins containing multiple points of diversification.

Evaluation of extractables in processed and unprocessed polymer materials used for pharmaceutical applications.

Polymeric materials are often used in pharmaceutical packaging, delivery systems, and manufacturing components. There is continued concern that chemical entities from polymeric components may leach into various dosage forms, particularly those that are comprised of liquids such as parenterals, injectables, ophthalmics, and inhalation products. In some cases, polymeric components are subjected to routine extractables testing as a control measure. To reduce the risk of discovering leachables during stability studies late in the development process, or components that may fail extractables release criteria, it is proposed that extractables testing on polymer resins may be useful as a screening tool. Two studies have been performed to evaluate whether the extractables profile generated from a polymer resin is representative of the extractables profile of components made from that same resin. The ELSIE Consortium pilot program examined polyvinyl chloride and polyethylene, and another study evaluated polypropylene and a copolymer of polycarbonate and acrylonitrile butadiene styrene. The test materials were comprised of polymer resin and processed resin or molded components. Volatile, semi-volatile, and nonvolatile chemical profiles were evaluated after headspace sampling and extraction with solvents of varying polarity and pH. The findings from these studies indicate that there may or may not be differences between extractables profiles obtained from resins and processed forms of the resin depending on the type of material, the compounds of interest, and extraction conditions used. Extractables testing of polymer resins is useful for material screening and in certain situations may replace routine component testing.

MCRs reshaped into a switchable microwave-assisted protocol toward 5-aminoimidazoles and dihydrotriazines.

A tunable microwave-assisted protocol for the synthesis of two biologically relevant families of heterocycles has been designed. Via a simple switch of reaction conditions, the same starting materials can be engaged in either an improved synthesis of the dihydrotriazine scaffold or a novel, first-in-class MCR to render the challenging 5-aminoimidazole nucleus in a single step. An additional first in class MCR is also reported utilizing guanidines to afford 2,5-aminoimidazoles.

Extractables characterization for five materials of construction representative of packaging systems used for parenteral and ophthalmic drug products.

Polymeric and elastomeric materials are commonly encountered in medical devices and packaging systems used to manufacture, store, deliver, and/or administer drug products. Characterizing extractables from such materials is a necessary step in establishing their suitability for use in these applications. In this study, five individual materials representative of polymers and elastomers commonly used in packaging systems and devices were extracted under conditions and with solvents that are relevant to parenteral and ophthalmic drug products (PODPs). Extraction methods included elevated temperature sealed vessel extraction, sonication, refluxing, and Soxhlet extraction. Extraction solvents included a low-pH (pH = 2.5) salt mixture, a high-pH (pH = 9.5) phosphate buffer, a 1/1 isopropanol/water mixture, isopropanol, and hexane. The resulting extracts were chemically characterized via spectroscopic and chromatographic means to establish the metal/trace element and organic extractables profiles. Additionally, the test articles themselves were tested for volatile organic substances. The results of this testing established the extractables profiles of the test articles, which are reported herein. Trends in the extractables, and their estimated concentrations, as a function of the extraction and testing methodologies are considered in the context of the use of the test article in medical applications and with respect to establishing best demonstrated practices for extractables profiling of materials used in PODP-related packaging systems and devices. LAY ABSTRACT: Plastic and rubber materials are commonly encountered in medical devices and packaging/delivery systems for drug products. Characterizing the extractables from these materials is an important part of determining that they are suitable for use. In this study, five materials representative of plastics and rubbers used in packaging and medical devices were extracted by several means, and the extracts were analytically characterized to establish each material's profile of extracted organic compounds and trace element/metals. This information was utilized to make generalizations about the appropriateness of the test methods and the appropriate use of the test materials.

CDER risk assessment exercise to evaluate potential risks from the use of nanomaterials in drug products.

The Nanotechnology Risk Assessment Working Group in the Center for Drug Evaluation and Research (CDER) within the United States Food and Drug Administration was established to assess the possible impact of nanotechnology on drug products. The group is in the process of performing risk assessment and management exercises. The task of the working group is to identify areas where CDER may need to optimize its review practices and to develop standards to ensure review consistency for drug applications that may involve the application of nanotechnology. The working group already performed risk management exercises evaluating the potential risks from administering nanomaterial active pharmaceutical ingredients (API) or nanomaterial excipients by various routes of administration. This publication outlines the risk assessment and management process used by the working group, using nanomaterial API by the oral route of administration as an example.

Selenium dioxide-mediated synthesis of α-ketoamides from arylglyoxals and secondary amines.

A facile and expeditious synthetic approach to α-ketoamides 3 is described. A series of α-ketoamides 3 was synthesized via reaction of selenium dioxide-mediated oxidative amidation between arylglyoxals 1 and secondary amines 2, and accelerated with microwave irradiation. Our findings indicate that constrained amines, such as piperazine and piperidine exhibit higher conversions for this transformation. This reaction was explored by synthesizing a series of α-ketoamides 3 from various arylglyoxals with cyclic and acyclic secondary amines.

Applications of ortho-phenylisonitrile and ortho-N-Boc aniline for the two-step preparation of novel bis-heterocyclic chemotypes.

Concise routes to five pharmacologically relevant bis-heterocyclic scaffolds are described. Significant molecular complexity is generated in a mere two synthetic operations enabling access to each scaffold. Routes are often improved by microwave irradiation and all utilize isocyanide-based multi-component reaction methods to incorporate the required diversity elements. Common reagents in all initial condensation reactions include 2-(N-Boc-amino)-phenyl-isocyanide 1, mono-Boc-phenylenediamine 2 and ethyl glyoxalate 3.

Hydrazine-mediated cyclization of Ugi products to synthesize novel 3-hydroxypyrazoles.

This report discloses a novel concise synthesis of a series of 3-hydroxypyrazoles 5 via a tandem Ugi/debenzylation /hydrazine-mediated cyclization sequence. Herein, n-butyl isocyanide 4b was utilized as an alternative to classical convertible isocyanides enabling high yielding hydrazine-mediated cyclization. Taken together, a novel class of 3-hydroxypyrazoles 5a-5i was synthesized with potential to be of interest in future library enrichment strategies.

Facile and rapid route for the synthesis of novel conformationally constrained norstatine analogs via PADAM-cyclization methodology.

The following report describes novel methodology for the rapid synthesis of unique conformationally constrained norstatine analogs of potential biological relevance. A PADAM (Passerini reaction - Amine Deprotection - Acyl Migration reaction) sequence is followed by a TFA-mediated microwave-assisted cyclization to generate the final benzimidazole isostere of the norstatine scaffold in moderate to good yields. The applicability of this solution phase methodology to the preparation of a small collection of compounds is discussed.

Facile, novel two-step syntheses of benzimidazoles, bis-benzimidazoles, and bis-benzimidazole-dihydroquinoxalines.

Three scaffolds of benzimidazoles, bis-benzimidazoles, and bis-benzimidazole-dihydroquinoxalines were synthesized via Ugi/de-protection/cyclization methodology. Benzimidazole forming ring closure was enabled under microwave irradiation in the presence of 10% TFA/DCE. The methodology demonstrates the utility of 2-(N-Boc-amino)-phenyl-isocyanide for the generation of new molecular diversity.

Ugi/Robinson-Gabriel reactions directed toward the synthesis of 2,4,5-trisubstituted oxazoles.

This Letter discloses a novel concise synthesis of a series of 2,4,5-trisubstituted oxazoles via a tandem Ugi/Robinson-Gabriel sequence. Herein, 2,4-dimethoxybenzylamine 1 was used as an ammonia equivalent in combination with arylglyoxal 3 and supporting Ugi reagents, an isonitrile and carboxylic acid. As such the product of the acid treated Ugi intermediate is ideally configured to undergo a Robinson-Gabriel cyclodehydration reaction to yield the desired oxazole scaffold 5.

Identification of novel DNA methylation inhibitors via a two-component reporter gene system.

BACKGROUND: Targeting abnormal DNA methylation represents a therapeutically relevant strategy for cancer treatment as demonstrated by the US Food and Drug Administration approval of the DNA methyltransferase inhibitors azacytidine and 5-aza-2'-deoxycytidine for the treatment of myelodysplastic syndromes. But their use is associated with increased incidences of bone marrow suppression. Alternatively, procainamide has emerged as a potential DNA demethylating agent for clinical translation. While procainamide is much safer than 5-aza-2'-deoxycytidine, it requires high concentrations to be effective in DNA demethylation in suppressing cancer cell growth. Thus, our laboratories have embarked on the pharmacological exploitation of procainamide to develop potent DNA methylation inhibitors through lead optimization. METHODS: We report the use of a DNA methylation two-component enhanced green fluorescent protein reporter system as a screening platform to identify novel DNA methylation inhibitors from a compound library containing procainamide derivatives. RESULTS: A lead agent IM25, which exhibits substantially higher potency in GSTp1 DNA demethylation with lower cytotoxicity in MCF7 cells relative to procainamide and 5-aza-2'-deoxycytidine, was identified by the screening platform. CONCLUSIONS: Our data provide a proof-of-concept that procainamide could be pharmacologically exploited to develop novel DNA methylation inhibitors, of which the translational potential in cancer therapy/prevention is currently under investigation.

Two step syntheses of fused quinoxaline-benzodiazepines and bis-benzodiazepines.

A two-step solution phase synthesis employing a double UDC (Ugi/Deprotect/Cyclize) strategy has been utilized to obtain fused 6,7,6,6-quinoxalinone-benzodiazepines and 6,7,7,6-bis-benzodiazepines. Optimization of the methodology to produce these tetracyclic scaffolds was enabled by microwave irradiation, incorporation of trifluoroethanol as solvent, and the use of the convertible isocyanide, 4-tert-butyl cyclohexen-1-yl isocyanide.

Synthesis and structure-activity relationship study of 8-hydroxyquinoline-derived Mannich bases as anticancer agents.

To continue our early study on the structural modifications of clioquinol, more 8-hydroxyquinoline-derived Mannich bases were synthesized and examined for growth-inhibitory effect. Taken Mannich base 1 as our lead compound, upon replacement of either sulfonyl group with methylene group or piperazine ring with ethylenediamine group resulted in an appreciable increase in potency. On the other hand, as 8-hydroxyquinoline was replaced with phenol, 3-hydroxypyridine and 1-naphthol, a dramatic decrease in activity was observed, indicating that 8-hydroxyquinoline is a crucial scaffold for activity. Further 3D-QSAR analysis on HeLa cells revealed that both steric and electronic effects contributed equally to growth inhibition. Taken together, the structure-activity relationships obtained from both in vitro data and CoMFA model warrant a valuable reference for further study.

3,5-Diaryl-1H-pyrazole as a molecular scaffold for the synthesis of apoptosis-inducing agents.

The scaffold of 3,5-diaryl-1H-pyrazole was selected as a molecular template to synthesize novel growth-inhibitory agents in the present study. Our findings suggested that analogs bearing electron-withdrawing groups on one ring while electron-donating groups on another reveal significant activities. In particular, 26 bearing a 1,1'-biphenyl moiety displayed the most potent activity against OVCA, SW620, H460 and AGS cells with GI(50) values of 0.67, 0.89, 0.73 and 0.79 microM, respectively. The mechanistic study revealed that 26-mediated apoptosis-inducing effect on OVCA cells was, in part, attributed to the inhibition of protein kinase B/Akt activity, accompanied by the mitochondrial apoptotic pathway through the activation of caspase-9, caspase-3, as well as the cleavage of protein poly(ADP-ribose) polymerase (PARP) and DNA fragmentation. Further structure-activity relationship study employed by Comparative Molecular Field Analysis (CoMFA) was carried out with q(2) and R(2) values of 0.671 and 0.846, respectively.

Effect of altered temperature storage on the in vitro cellular uptake of liposome drug products.

The aim of this study was to evaluate whether temperature stress conditions affect the cellular uptake of liposomal doxorubicin, Doxil (DXL; Ortho Biotech, Raritan, New Jersey, USA), and liposomal daunorubicin, DaunoXome (DXM; Gilead Sciences, San Dimas, California, USA). Uptake of these cytotoxic compounds is essential for their pharmacological effect. Commercially available DXL and DXM were stressed for 6 days under altered temperature conditions of 22 and 50 degrees C, as compared to storage in their buffered formulations at the labeled temperature of 4 degrees C. The cellular uptake of the liposomal drugs was measured by fluorescence intensity in human ovarian SKOV-3 and murine macrophage J774A.1 cell lines following a 4-hour exposure to DXL or DXM. There was a 5- to 10-fold increase in the cellular uptake of DXL and DXM in both cell lines after stress exposure to 50 degrees C. Exposure of DXL to 22 degrees C stress decreased its uptake by SKOV-3 cells, when compared to exposure of DXL to 4 degrees C control conditions. A cell-based uptake assay may provide a means to assess changes in the functional activity of liposomes in conjunction with evaluation of their physicochemical properties in order to evaluate the stability and integrity of liposomes.