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21.
One approach for the synthesis of isoindolinones, a privileged bioactive heterocyclic core structure, involves a condensation reaction of o-phthaldialdehydes with a suitable nitrogen-containing nucleophile. This fascinating reaction is revisited here in the context of the use of o-phthaldialdehydes that contain additional substituents in the aromatic ring leading to a detailed analysis of the regioselectivity of the reaction. Eleven monosubstituted o-phthaldialdehydes were synthesised and reacted with alanine. The regioselectivity observed across the eleven substrates led to the design of a disubstituted substrate that reacted with very high control. A gram-scale reaction followed by esterification gave one major regioisomer in high yield. In addition, the regioselectivity observed on reaction of two novel monodeuterated substrates led to an increased mechanistic understanding. 相似文献
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Isothiourea‐Catalysed Acylative Kinetic Resolution of Aryl–Alkenyl (sp2 vs. sp2) Substituted Secondary Alcohols 下载免费PDF全文
Stefania F. Musolino Dr. O. Stephen Ojo Prof. Nicholas J. Westwood Dr. James E. Taylor Prof. Andrew D. Smith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18916-18922
The non‐enzymatic acylative kinetic resolution of challenging aryl–alkenyl (sp2 vs. sp2) substituted secondary alcohols is described, with effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kinetic resolution of a wide range of aryl–alkenyl substituted alcohols has been evaluated, with either electron‐rich or naphthyl aryl substituents in combination with an unsubstituted vinyl substituent providing the highest selectivity (S=2–1980). The use of this protocol for the gram‐scale (2.5 g) kinetic resolution of a model aryl–vinyl (sp2 vs. sp2) substituted secondary alcohol is demonstrated, giving access to >1 g of each of the product enantiomers both in 99:1 e.r. 相似文献
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Pasinszki T Vass G Klapstein D Westwood NP 《The journal of physical chemistry. A》2012,116(13):3396-3403
Cyanoformyl chloride and cyanoformyl bromide, XC(O)CN (X = Cl and Br), have been investigated in the gas phase by UV photoelectron and mid-infrared spectroscopies. The ground-state geometries of the neutral molecules have been obtained from quantum-chemical calculations at the B3LYP and CCSD(T) levels using the aug-cc-pVTZ basis set. The individual spectroscopies provide a detailed investigation into the vibrational and electronic character of the molecules and are supported by quantum-chemical calculations. The results are compared to data for structurally and chemically related molecules. 相似文献
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The National Analytical Reference Laboratory has synthesized and characterized 67 anabolic steroid marker metabolites, both unlabelled and deuterated, and 37 key glucuronide and sulfate steroid conjugate pure substance reference materials. Work is also in process to establish their full traceability so that they can be issued as certified and primary reference materials. Both identity and purity have been rigorously characterized using a number of techniques and a primary method for purity assessment developed, based gas chromatography combined with flame ionization detection for the parent steroids and HPLC with evaporative light scattering detection for non-volatile steroid conjugates. Strategies for establishing traceability and for estimating measurement uncertainty are reported. The strategies described are considered applicable to a wide range of organic pure substance reference materials. 相似文献
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This paper looks at planning within the present distribution environment, paying particular attention to recent trends and developments. The idea of a depot as the traditional building block of a distribution network is questioned and the various functions of a regional depot are explored.The concept of a transit point as a simple alternative to a depot is developed and examples are given of its use in practice. Several refinements are available, particularly in the area of trailer technology, and these are discussed. The necessary support system for transit point operation is identified and finally the implications for distribution planning are considered. 相似文献
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Andrew N. Boa Stephen Clark Paul R. Hirst Robert Westwood 《Tetrahedron letters》2003,44(52):9299-9302
6-Oxiranyl- and 3-oxiranyl-2-phenylquinoline-4-carboxylic acid diisopropylamides react with secondary amines and lithium amides to give (aminohydroxyethyl)quinolines but with opposite regioselectivities. Upon epoxidation of 3-formylquinoline 2 a 5:1 mixture of atropisomers is formed. This ratio is maintained upon epoxide ring-opening with amines in ethanol at reflux, but with lithium amides at room temperature a 1.3:1 ratio of isomers is obtained. 相似文献
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