The chemistry of polycyclic arene imines. III. N-alkylation of phenanthrene 9,10-imineN-alkylation of phenanthrene 9,10-imine

Phenanthrene 9,10-imine ( 1 ) was shown to undergo N-alkylation without aziridine ring cleavage by (a) metallation with sodium methylsulfinylmethide followed by addition of an alkyl halide at −20° (b) reaction of 1 , sodium hydride and the halide in dimethylformamide at 40° (c) treatment of a dichloromethane solution of 1 , the halide and triethylbenzylammonium chloride with aqueous sodium hydroxide under phase transfer conditions. The syntheses of N-isopropyl-, N-butyl-, N-pentyl-, N-allyl- and N-benzylphenanthrene 9,10-imine ( 2–6 ) are described.     

Confinement in nanopores at the oxide/water interface: modification of alumina adsorption properties

There is limited knowledge on the influence of the pore size on surface phenomena (adsorption, dissolution, precipitation, etc.) at the oxide/water interface and a better understanding of the space confinement in nanoscale pores should have practical implications in different areas, such as transport of contaminants in the environment or heterogeneous catalyst preparation, to name a few. To investigate the modifications of the oxide adsorption properties at the oxide/water interface in a confined environment, the surface acidobasic and ion adsorption properties of six different aluminas (5 porous commercial aluminas with pore diameters ranging from 25 to 200 A and 1 non-porous alumina) were determined by means of acid-base titration and Ni(II) adsorption. It is shown that the confinement has a moderate impact on the alumina adsorption capacity because all materials have similar surface charging behaviours and ion saturation coverages. However, a confined geometry has a much larger impact on the ion adsorption constants, which decrease drastically when the average pore diameter decreases below 200 A. These results are discussed in terms of nanoscale pore space confinement.     

Temporary Generation of a Cyclopropyl Oxocarbenium Ion Enables Highly Diastereoselective Donor–Acceptor Cyclopropane Cycloaddition

A novel formal [3+2] cycloaddition of cyclopropylacetals and aldehydes was developed, and the resulting trisubstituted tetrahydrofurans display three new chiral centers formed with highly diastereoselectivity. This method is stereocomplementary to most previously reported cycloadditions of malonate diesters, relies on the transient generation of cyclopropyl oxocarbenium ions, proceeds under mild conditions, and is based on the concept of temporary activation of an otherwise inert protecting group.     

Bounded Extremal and Cauchy–Laplace Problems on the Sphere and Shell

In this work, we develop a theory of approximating general vector fields on subsets of the sphere in ℝ ⁿ by harmonic gradients from the Hardy space H ^p of the ball, 1<p<∞. This theory is constructive for p=2, enabling us to solve approximate recovery problems for harmonic functions from incomplete boundary values. An application is given to Dirichlet–Neumann inverse problems for n=3, which are of practical importance in medical engineering. The method is illustrated by two numerical examples.     

Design,synthesis and spectroscopic characterisation of a focused library based on the polyandrocarpamine natural product scaffold

A focused library based on the marine natural products polyandrocarpamines A ( 1 ) and B ( 2 ) has been designed and synthesised using parallel solution‐phase chemistry. In silico physicochemical property calculations were performed on synthetic candidates in order to optimise the library for drug discovery and chemical biology. A library of ten 2‐aminoimidazolone products ( 3–12 ) was prepared by coupling glycocyamidine and a variety of aldehydes using a one‐step stereoselective aldol condensation reaction under microwave conditions. All analogues were characterised by NMR, UV, IR and MS. The library was evaluated for cytotoxicity towards the prostate cancer cell lines, LNCaP, PC‐3 and 22Rv1. Copyright © 2013 John Wiley & Sons, Ltd.