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Historically used in stoichiometric hydroalumination chemistry, recent advances have transformed aluminium hydrides into versatile catalysts for the hydroboration of unsaturated multiple bonds. This catalytic ability is founded on the defining reactivity of aluminium hydrides with alkynes and alkenes: 1,2‐hydroalumination of the unsaturated π‐system. This manuscript reports the aluminium hydride catalyzed dehydroborylation of terminal alkynes. A tethered intramolecular amine ligand controls reactivity at the aluminium hydride centre, switching off hydroalumination and instead enabling selective reactions at the alkyne C−H σ‐bond. Chemoselective C−H borylation was observed across a series of aryl‐ and alkyl‐substituted alkynes (21 examples). On the basis of kinetic and density functional theory studies, a mechanism in which C−H borylation proceeds by σ‐bond metathesis between pinacolborane (HBpin) and alkynyl aluminium intermediates is proposed., The aluminium hydride catalyzed dehydroborylation of terminal alkynes is reported. By using a tethered‐intramolecular‐amine Lewis base as a ligand at the aluminium hydride centre the reactivity is controlled. Hydroalumination is switched off and selective reactions at the alkyne C−H σ‐bond are enabled.

A selective aziridinium ring-opening was used to etherify an α-aryl-β-amino alcohol with stereochemical retention. This transformation was achieved in a biphasic system to address phenoxide solubility and the formation of a sulfonate ester impurity. The protecting group strategy was directed by a stability study of the activated α-aryl-β-amino alcohol in this system. Process analytical techniques were used to establish reaction understanding, and mixing on large scale was modeled in silico. The process provided a selective and efficient method of preparing the nonsteroidal, inhaled selective glucocorticoid receptor modulator AZD7594.

In 2007 the members of the ACS Green Chemistry Institute® Pharmaceutical Roundtable assembled a list of key green chemistry research areas to both identify transformations that would benefit from improvements in process greenness and to encourage academic research to this end. The list provided the topics for a review of the literature, published in 2007 in the journal Green Chemistry. As part of the 10th anniversary of the founding of the Roundtable in 2015, the membership revisited the list. This article discusses the selection of the revised list, the updated 10 key green chemistry research areas, 2 solvent themes and the emerging area of medium molecules that resulted from the exercise.

Enzymes are a catalytic class of proteins that possess high specificity, selectivity and biocompatibility, which makes them ideal for multiple applications in industrial production and biotechnology. However, the use of enzymes in such applications is limited due to their low operational stability and increased cost attributed to difficulty of purification and reuse. Immobilization of enzymes onto nano-sized solid supports has emerged as a potential solution to these shortcomings with a trade-off of a percentage of activity loss upon immobilization. Herein, a comprehensive study of enzyme immobilization techniques with emphasis on active-surface decontamination applications is presented. In Chapter 1, an overview of the potential uses of enzymes and enzyme immobilization techniques is given. Benefits of enzyme-nanosupport conjugates in industrial catalysis, energy production (i.e. biofuels and biofuel cells), biosensing and bioactive coatings are discussed with emphasis on enzyme-based decontamination coatings. It is emphasized that enzyme-based conjugates are capable of increasing enzyme stability at operational conditions used in industrial production of fine chemicals, pharmaceuticals and foods. Also, this Chapter emphasizes the benefits of enzyme immobilization in regard to the development of the next generation of biosensors with enhanced selectivity and specificity or biofuel cells that do not require a membrane, and thus allow miniaturization. Additionally, coatings capable of decontaminating pathogens such as bacteria and spores can be produced through the incorporation of enzyme-nanomaterial conjugates. Finally, the chapter provides new perspectives and future directions in enzyme-based biotechnology. A. Campbell, C. Dong, C. Xiang, N. Q. Wu and C. Z. Dinu, “Enzyme-Based Technologies: Perspectives and Opportunities” Accepted to Green Polymer Chemistry: Biocatalysis and Biomaterials, ACS Symposium Series 2012. In Chapter 2, the impacts of the reactions that take place upon enzyme immobilization at the nanointerface are discussed and the effects of multiple variables present in the immobilization process on enzyme retained activity are identified. These variables include nanosupport characteristics (i.e. physical and chemical properties, rate of curvature), enzyme properties (i.e. surface properties, molecular weight, isoelectric point) and immobilization technique (i.e. chemical or physical binding). Prior to immobilization of the selected enzymes (i.e. soybean peroxidase (SBP), chloroperoxidase (CPO) and glucose oxidase (GOX)) all nanosupports (i.e. single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and graphene oxide nanosheets (GON)) are chemically functionalized under user-controlled conditions through strong acids treatment and characterized in terms of structure and morphology. A comparison of how the characteristics of both the nanosupports used as well as immobilization technique employed affect retained activity in an enzyme specific manner is also presented. A. Campbell,…

Most recent advances in metallation chemistry have centred on the bulky secondary amide 2,2,6,6-tetramethylpiperidide (TMP) within mixed metal, often ate, compositions. However, the precursor amine TMP(H) is rather expensive so a cheaper substitute would be welcome. Thus this study was aimed towards developing cheaper non-TMP based mixed-metal bases and, as cis-2,6- dimethylpiperidide (cis-DMP) was chosen as the alternative amide, developing cis-DMP zincate chemistry which has received meagre attention compared to that of its methyl-rich counterpart TMP. A new lithium diethylzincate, [(TMEDA)LiZn(cis-DMP)Et] (TMEDA=N,N,N′,N′- tetramethylethylenediamine) has been synthesised by co-complexation of Li(cis-DMP), EtZn and TMEDA, and characterised by NMR (including DOSY) spectroscopy and X-ray crystallography, which revealed a dinuclear contact ion pair arrangement. By using N,N-diisopropylbenzamide as a test aromatic substrate, the deprotonative reactivity of [(TMEDA)LiZn(cis-DMP)Et] has been probed and contrasted with that of the known but previously uninvestigated di-tert-butylzincate, [(TMEDA)LiZn(cis-DMP)tBu]. The former was found to be the superior base (for example, producing the ortho-deuteriated product in respective yields of 78 % and 48 % following D O quenching of zincated benzamide intermediates). An 88 % yield of 2-iodo-N,N-diisopropylbenzamide was obtained on reaction of two equivalents of the diethylzincate with the benzamide followed by iodination. Comparisons are also drawn using 1,1,1,3,3,3-hexamethyldisilazide (HMDS), diisopropylamide and TMP as the amide component in the lithium amide, EtZn and TMEDA system. Under certain conditions, the cis-DMP base system was found to give improved results in comparison to HMDS and diisopropylamide (DA), and comparable results to a TMP system. Two novel complexes isolated from reactions of the di-tert-butylzincate and crystallographically characterised, namely the pre-metallation complex [{(iPr)N(Ph)Ci'O}LiZn(cis-DMP)tBu ] and the post-metallation complex [(TMEDA)Li(cis-DMP){2-[1-C(=O) N(iPr)]CH}Zn(tBu)], shed valuable light on the structures and mechanisms involved in these alkali-metal-mediated zincation reactions. Aspects of these reactions are also modelled by DFT calculations. Amide austerity: Lithium amidozincate bases replacing expensive TMP (2,2,6,6-tetramethylpiperidide) by inexpensive cis-DMP (cis-2,6- dimethylpiperidide) have been synthesised (see scheme) and utilised for the ortho-deprotonation of a benzamide substrate for comparision with their TMP and other common amido analogues.

A general thermolysis reaction for the transformation of Group 1 TMP compounds (LiTMP, NaTMP, KTMP) to 1-aza-allylic TTHP derivatives is reported. TMEDA accelerates the reaction and produces the crystalline complexes [(TMEDA)LiTTHP] and [(TMEDA·NaTTHP)2]. Methane elimination during the transformational process was confirmed via TVA coupled to MS.

El programa BTEC es un programa de estudios que permite obtener una cualificación profesional o laboral. Este recurso está preparado para ayudar al alumno en el curso BTEC First, nivel 2, sector profesional arte y diseño y se divide en dos secciones: conocimientos y destrezas; la primera sección comprende cinco unidades y la segunda sección, tres unidades. Incluye actividades de evaluación en cada unidad que cubren todos los criterios de ésta para ofrecer a los estudiantes la oportunidad de practicar sus tareas y profundizar en el conocimiento y la comprensión de la materia. SC Biblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 planta; 28014 Madrid; Tel. +34917748000; biblioteca@mecd.es GBR