Phosphatidylinositide 3-kinase (PI3K) and PI3K-related kinase (PIKK) activity contributes to radioresistance in thyroid carcinomas.

Anaplastic (ATC) and certain follicular thyroid-carcinomas (FTCs) are radioresistant. The Phosphatidylinositide 3-kinase (PI3K) pathway is commonly hyperactivated in thyroid-carcinomas. PI3K can modify the PI3K-related kinases (PIKKs) in response to radiation: How PIKKs interact with PI3K and contribute to radioresistance in thyroid-carcinomas is unknown.

Dissemination via the lymphatic or angiogenic route impacts the pathology, microenvironment and hypoxia-related drug response of lung metastases.

Complications associated with the development of lung metastases have a detrimental effect on the overall survival rate of many cancer patients. Preclinical models that mimic the clinical aspects of lung metastases are an important tool in developing new therapy options for these patients. The commonly used intravenous models only recapitulate dissemination of cancer cells to the lungs via the haematological route.

A novel approach to the site-selective dual labelling of a protein chemoselective cysteine modification.

Local protein microenvironment is used to control the outcome of reaction between cysteine residues and 2,5-dibromohexanediamide. The differential reactivity is exploited to introduce two orthogonal reactive handles onto the surface of a double cysteine mutant of superfolder green fluorescent protein in a regioselective manner. Subsequent elaboration with commonly used thiol and alkyne containing reagents affects site-selective protein dual labelling.

Acyl hydrazides as acyl donors for the synthesis of diaryl and aryl alkyl ketones.

In this communication we describe a novel strategy for the formation of valuable diaryl and aryl alkyl ketones from acyl hydrazides. A wide variety of ketones are prepared and the mild reaction conditions allow for the use of a range of functionalities, especially in the synthesis of diaryl ketones.

Metal-free, hydroacylation of C=C and N=N bonds via aerobic C-H activation of aldehydes, and reaction of the products thereof.

In this report, a thorough evaluation of the use of aerobically initiated, metal-free hydroacylation of various C=C and N=N acceptor molecules with a wide range of aldehydes is presented. The aerobic-activation conditions that have been developed are in sharp contrast to previous conditions for hydroacylation, which tend to use transition metals, peroxides that require thermal or photochemical degradation, or N-heterocyclic carbenes. The mildness of the conditions enables a number of reactions involving sensitive reaction partners and, perhaps most significantly, allows for α-functionalised chiral aldehydes to undergo radical-based hydroacylation with complete retention of optical purity.

A mild synthesis of N-functionalised bromomaleimides, thiomaleimides and bromopyridazinediones.

Bromomaleimides are useful building blocks in synthesis and powerful reagents for the selective chemical modification of proteins. A mild new synthesis of these reagents is described, along with the convenient transferability of the approach to dithiomaleimides and bromopyridazinediones.

Reversible protein affinity-labelling using bromomaleimide-based reagents.

Reversible protein biotinylation is readily affected via conjugation with a bromomaleimide-based reagent followed by reductive cleavage. The intermediate biotinylated protein constructs are stable at physiological temperature and pH 8.0.

Photodetachment spectra of deprotonated fluorescent protein chromophore anions.

Isolated model anion chromophores of the green and cyan fluorescent proteins were generated in an electrospray ion source, and their photodetachment spectra were recorded using photoelectron imaging. Vertical photodetachment energies of 2.85(10) and 4.

Diastereomer configurations from joint experimental-computational analysis.

The potential of the approach combining nuclear magnetic resonance (NMR) spectroscopy, relaxed grid search (RGS), molecular dynamics (MD) simulations, and quantum mechanical (QM) calculations for the determination of diastereomer configurations is demonstrated using four diastereomers of a trisubstituted epoxide. Since the change in configuration of the chiral center is expected to change the distribution of conformer populations (including those of side-chain rotamers), changes in NMR parameters [chemical shifts, J couplings, and nuclear Overhauser effects (NOEs)] are expected. The method therefore relies on (1) identification of possible conformations in each diastereomer using relaxed grid search analysis and MD simulations; (2) geometry optimizations of conformers selected from step (1), followed by calculations of their relative energies (populations) using QM methods; (3) calculations of averaged NMR parameters using QM methods; (4) matching calculated and experimental values of NMR parameters of diastereomers.

Bioconjugation of green fluorescent protein via an unexpectedly stable cyclic sulfonium intermediate.

Smooth converter: Bioconjugation of superfolder GFP involving the formation of an unusually stable, and unprecedented, cyclic sulfonium species is described. This sulfonium can undergo smooth reaction with a range of nucleophiles to give sulfur-, selenium- and azide-modified GFP derivatives in high conversions.

Functionalisation of aldehydes via aerobic hydroacylation of azodicarboxylates 'on' water.

Herein we report the functionalisation of aldehydes via hydroacylation of azodicarboxylates. A range of functionalised aldehydes are employed as the limiting reagent including chiral non-racemic aldehydes bearing α-stereocentres which are functionalised giving access to enantiomerically pure products. The resultant hydrazides can be employed as acyl donors in the synthesis of amides.

Hydroacylation of alpha,beta-unsaturated esters via aerobic C-H activation.

The development of methods for carbon-carbon bond formation under benign conditions is an ongoing challenge for the synthetic chemist. In recent years there has been considerable interest in using selective C-H activation as a direct route for generating reactive intermediates. In this article, we describe the use of aldehyde auto-oxidation as a simple, clean and effective method for C-H activation, resulting in the generation of an acyl radical.

Inhibition of HIV-1 replication by isoxazolidine and isoxazole sulfonamides.

Targeting host factors is a complementary strategy for the development of new antiviral drugs. We screened a library of isoxazolidine and isoxazole sulfonamides and found four compounds that inhibited HIV-1 infection in human CD4+ lymphocytic T cells with no toxicity at IC(90) concentrations. Structure-activity relationship showed that benzyl sulfonamides and a halo-substituted aromatic ring on the heterocycle scaffold were critical for antiretroviral activity.

An efficient asymmetric synthesis of the potent beta-blocker ICI-118,551 allows the determination of enantiomer dependency on biological activity.

A highly efficient, practical and flexible two-step asymmetric synthesis of the beta(2)-selective beta-blocker ICI 118,551 is reported, allowing an unambiguous determination of the dependency of biological activity with optical activity, revealing the S,S-enantiomer to be the most potent.

A facile synthesis of dibenzopyrroloazepinones as tetracyclic allocolchicinoids--an unusual 1,2-phenyl shift.

A facile synthesis of dibenzopyrroloazepinones via an electrophilic cyclisation of a biphenyl-acyliminium ion is described; an unusual 1,2-phenyl shift occurs when the C-1' carbon is the more nucleophilic than the C-2' carbon.

Dioxygen mediated hydroacylation of vinyl sulfonates and sulfones on water.

Herein we report a mild, facile method for the preparation of 1,4-keto-sulfonates and sulfones on water. Further synthetic manipulations can result in products that are not readily accessed by hydroacylation of electron rich alkenes.

3,5-Isoxazoles from alpha-bromo-pentafluorophenyl vinylsulfonates: synthesis of sulfonates and sulfonamides.

The regioselective 1,3-dipolar cycloaddition of alpha-bromo-pentafluorophenyl vinylsulfonate with nitrile oxides has been used to rapidly access a range of 3,5-isoxazoles which could be converted directly to their corresponding sulfonamides.

Synthesis of unsymmetrical ketones via simple C-H activation of aldehydes and concomitant hydroacylation of vinyl sulfonates.

A new and simple protocol for the direct functionalisation of aldehydes with concomitant conversion into ketones via C-C bond formation has been developed. The reaction effectively enables the direct C-H activation of an aldehyde by mixing of an aldehyde and a vinyl sulfonate under aerobic conditions or using hydrogen peroxide as a sub-stoichiometric reagent.

Development of a practical Buchwald-Hartwig amine arylation protocol using a conveniently prepared (NHC)Pd(R-allyl)Cl catalyst.

Continuing efforts to establish a more general "user-friendly" protocol for the palladium-catalysed arylation of amines (Buchwald-Hartwig reaction) are described herein. Significant advances have been made through the use of the versatile (SIPr)Pd(methallyl)Cl complex in conjunction with the reliable base lithium hexamethyldisilazide (LHMDS).

Carboxylate binding in polar solvents using pyridylguanidinium salts.

A series of thiourea and guanidinium derivatives have been prepared and their ability to bind a carboxylate group has been investigated. Guanidinium 33, featuring two additional amides and a pyridine moiety, proved to be the most potent carboxylate binding site and was able to bind acetate in aqueous solvent systems (K(ass) = 480 M(-1) in 30% H(2)O-DMSO). The pyridine moiety is critical to obtaining strong binding, and comparison with the binding properties of analogous compounds in which the pyridine is replaced by a benzene ring provides a striking example of enthalpy-entropy compensation.

Microwave enhanced palladium catalysed coupling reactions: a diversity-oriented synthesis approach to functionalised flavones.

Microwave enhanced diversity-oriented synthesis (MEDOS) using palladium catalysed protocols is introduced as a powerful new strategy for the synthesis of systematically modified small molecules and is highlighted by application to functionalised flavones.

Tirapazamine administered as a neoadjuvant to radiotherapy reduces metastatic dissemination.

Purpose: The level of hypoxia in primary tumors has been linked both clinically and experimentally to the incidence of metastases. This study was designed to address the effect of selectively targeting hypoxic cells in primary tumors on subsequent presentation of metastasis.

Experimental Design: The murine KHT model was used as a reproducible temporal and spatial onset of metastases is revealed following treatment of primary ( approximately 400 mm(3)) s.