para-Selective C-H amidation of simple arenes with nitriles

A para-selective C-H amidation of simple arenes with nitriles has been developed. By increasing the amount of arenes, a further meta-selective C-H arylation of the produced amides occurred. Both steric and electronic effects are utilized to control the selectivity, resulting in only para-selective amidation products. The readily available nitriles as amidation reagents instead of amides makes the synthesis of N-arylamides more accessible

The Child Silenced by Social Anxiety

This meta-synthesis explores the subject of selective mutism across multiple age groups. Selective mutism is present in a very small percentage of students. Given the small number of students that have this disorder there is limited resources and professional collaboration options available for teachers. The low incident rate of selective mutism often leads to students being forgotten about in the classroom setting. Teachers do not know how to help them overcome their disorder and the students are not able to ask for the help they need. This exploration into selective mutism reviewed 30 articles on the topic and attempted to provide identifying characteristics of the disorder as well as interventions for educators to implement while working with students selective mutism

Flexible synthesis of polyfunctionalised 3-fluoropyrroles

An efficient and selective approach for the synthesis of polyfunctionalised 3-fluoropyrroles has been developed starting from commercial aldehydes. The methodology is concise, efficient and allows for the modular and systematic assembly of polysubstituted 3-fluoropyrroles. This synthesis provides an alternative and highly convergent strategy for the generation of these chemically and biologically important units

Synthetic routes to Bis-Calix [n]areness : a thesis presented in partial fulfilment of the requirements for the degree of Masterate of Science in Chemistry at Massey University

The literature procedures for the targeted syntheses of p-tert-butylcalix[4]arene, p-tert-butylcalix[5]arene, p-tert-butylcalix[6]arene, p-tert-butylcalix[7]arene, and p-tert-butylcalix[8]arene have been repeated successfully. In the case of p-tert-butylcalix[4]arene, alterations led to a less capricious procedure, synthesis of the pure product directly and in higher yield. The residual xylene and toluene solutions from the targeted p-tert-butylcalix[8]arene preparation were utilised to obtain workable quantities of the rare calix[5]- and calix[7]arenes, a protocol that is far simpler and less time-consuming than the low-yielding targeted synthesis of these compounds. Dealkylation of p-tert-butylcalix[n]arenes is best accomplished at 30°C in 0.16-0.05 molL−¹ toluene solution. The insolubility of calix[8]arene in all common organic solvents is expected to limit its synthetic use. Two new protocols have been devised for the highly selective mono-O-alkylation of calixarenes 4 through 8. This work represents the realisation of the first selective functionalisation methods that are applicable to the calixarene family, and also the first selective functionalisation of a calix[7]arene. These findings will lead to more efficient synthesis of multiple calixarenes (cf. Chapter 3) and may allow for a better understanding of the reasons for selectivity in calixarene-O-alkylations. We have been able to synthesise a variety of bis-calixarenes by two different routes. Glaser-Hay coupling allowed the synthesis of symmetrical diyne bridged bis-calix[4, 6 and 8]arenes in high yield. Extension of the first general mono-O-alkylation procedure for calixarenes has made it possible to synthesise hom o-bis-calixarenes in good yield in one step from the parent calixarenes. The unexpected formation of monobromoxylyl calixarenes allows the prospect of the synthesis of hetero-bis-calixarenes under more forcing conditions. Most importantly this allows us to further explore the chemistry of bis-calixarenes by making them readily available (in large quantities) for more elaborate syntheses

Ligand design for site-selective installation of Pd and Pt centers to generate homo- and heteropolymetallic motifs

The modular synthesis of a series of nitrogen-rich polydentate ligands that feature a common pincer-type framework is reported. These ligands allow for site-selective installation of palladium and platinum to give rise to bi- and trimetallic complexes that have d^(8)–d^(8) interactions

Novel Fmoc-Polyamino Acids for Solid-Phase Synthesis of Defined Polyamidoamines

A versatile solid-phase approach to sequence-defined polyamidoamines was developed. Four different Fmoc-polyamino acid building blocks were synthesized by selective protection of symmetrical oligoethylenimine precursors followed by introduction of a carboxylic acid handle using cyclic anhydrides and subsequent Fmoc-protection. The novel Fmoc-polyamino acids were used to construct polyamidoamines demonstrating complete compatibility to standard Fmoc reaction conditions. The straightforward synthesis of the building blocks and the high efficiency of the solid-phase coupling reactions allow the versatile synthesis of defined polycations

Chelated Ruthenium Catalysts for Z-Selective Olefin Metathesis

We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands that catalyze highly Z-selective olefin metathesis. A very simple and convenient procedure for the synthesis of such catalysts has been developed. Intramolecular C–H bond activation of the NHC ligand, promoted by anion ligand substitution, forms the appropriate chelate for stereocontrolled olefin metathesis

A Simple Nickel Catalyst Enabling an E‐Selective Alkyne Semihydrogenation

Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom economic reducing agent dihydrogen (H 2 ), only few catalysts for the challenging E ‐selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E ‐selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E ‐alkenes employing H 2 which could serve as a general method for synthesis.DFG, 352364740, Diwasserstoff-vermittelte nachhaltige BindungsknüpfungsreaktionenTU Berlin, Open-Access-Mittel - 201

Regioselective and stoichiometrically controlled conjugation of photodynamic sensitizers to a HER2 targeting antibody fragment

The rapidly increasing interest in the synthesis of antibody–drug conjugates as powerful targeted anticancer agents demonstrates the growing appreciation of the power of antibodies and antibody fragments as highly selective targeting moieties. This targeting ability is of particular interest in the area of photodynamic therapy, as the applicability of current clinical photosensitizers is limited by their relatively poor accumulation in target tissue in comparison to healthy tissue. Although synthesis of porphyrin–antibody conjugates has been previously demonstrated, existing work in this area has been hindered by the limitations of conventional antibody conjugation methods. This work describes the attachment of azide-functionalized, water-soluble porphyrins to a tratuzumab Fab fragment via a novel conjugation methodology. This method allows for the synthesis of a homogeneous product without the loss of structural stability associated with conventional methods of disulfide modification. Biological evaluation of the synthesized conjugates demonstrates excellent selectivity for a HER2 positive cell line over the control, with no dark toxicity observed in either case