Synthesis and polymerization of p-(p′-vinylbenzoyl)-peroxybenzoic acid tert-butylester: A monomer containing a photodissociable radical source

In a previous report we have shown that efficiently photodecomposable, but thermally stable, peresters can be made from a compound that contains both a triplet photosensitizer functionality and a perester group. This fundamental approach has been extended to make a novel vinyl monomer containing a triplet sensitizer and a perester group. Thus, the monomer p-vinylbenzoyl-p-tert-butyl perbenzoate (VBPE) has been synthesized and polymerized by normal procedures without loss of perester activity. The resulting polymer perester can be used as an efficient photolabile radical source by irradiating at the λ_max of the benzophenone carbonyl moiety. The homopolymer (PVBPE) and copolymers with other monomers, such as styrene, could be photocrosslinked with high efficiency. Copolymers of VBPE and styrene containing low percentages of VBPE have been used to initiate graft chains of poly(methyl methacrylate) by irradiating a solution of the copolymer in methyl methacrylate at 366 nm.     

Photoinitiated polymerization of vinyl monomers by benzophenone t-butyl peresters

Benzophenone peresters undergo efficient photodecomposition when irradiated at 366 nm. This article reports peresters derived from benzophenone p,p′-dicarboxylic acid 1 which may produce radicals at two different centers in the same molecule. These peresters represent a unique new example of an efficient photoinitiator for acrylate and styrene polymerization.      

Approach to the perhydroisoindole system in cytochalasin B

The synthesis of the perhydroisoindole systems 17a, b, 22 and 23 is described using the following sequence of reactions. Diels-Alder cycloaddition of silyloxydienes 4 with methyl acrylate leads, after methanolysis, to cyclohexenonecarboxylates 6, subsequent acetalization and epoxidation of the α,β-unsaturated esters 7 yields the epoxy esters 8 and 9. Conversion of these esters into acyl chlorides 11, via the sodium salts 10, and subsequent treatment with an amine component (phenylalanine methyl ester, diethyl aminomalonate and ethyl 2-amino benzoyl-acetate) produces the epoxy carbonamides 12, 15 and 18, respectively. These epoxy amides are subjected to acid-catalyzed hydrolysis to give the cyclohexenonecarbonamides 13, 16 and 19, respectively. Subsequent ring-closure of the amides 16 and 19 with base leads to the perhydroisoindole derivatives 17a, b and 22, respectively. The formation of 22 proceeds via a concomitant benzoyl transfer reaction. The amide 13 failed to ring-close. A by-product of the acid treatment of 18 is 21 which with base undergoes a benzoyl transfer to perhydroisoindole 23. The structures of the products 9a, 22 and 23 were ascertained by means of an X-ray analysis.     

Understanding the role of sodium during adsorption: a force field for alkanes in sodium-exchanged faujasites

We have developed a united atom force field able to accurately describe the adsorption properties of linear alkanes in the sodium form of FAU-type zeolites. This force field successfully reproduces experimental adsorption properties of n-alkanes over a wide range of sodium cation densities, temperatures, and pressures. The force field reproduces the sodium positions in dehydrated FAU-type zeolites known from crystallography, and it predicts how the sodium cations redistribute when n-alkanes adsorb. The cations in the sodalite cages are significantly more sensitive to the n-alkane loading than those in the supercages. We provide a simple expression that adequately describes the n-alkane Henry coefficient and adsorption enthalpy as a function of sodium density and temperature at low coverage. This expression affords an adequate substitute for complex configurational-bias Monte Carlo simulations. The applicability of the force field is by no means limited to low pressure and pure adsorbates, for it also successfully reproduces the adsorption from binary mixtures at high pressure.     

Synthesis and properties of gradient copolymers based on 2‐phenyl‐2‐oxazoline and 2‐nonyl‐2‐oxazoline

In this study, the structure–property relationships for a series of statistical 2‐nonyl‐2‐oxazoline (NonOx) and 2‐phenyl‐2‐oxazoline (PhOx) copolymers were investigated for the first time. The copolymerization kinetics were studied and the reactivity ratios were calculated to be r_NonOx = 7.1 ± 1.4 and r_PhOx = 0.02 ± 0.1 revealing the formation of gradient copolymers. The synthesis of a systematical series of NonOx–PhOx copolymers is described, whereby the amount of NonOx was increased in steps of 10 mol %. The thermal and surface properties were investigated for this series of well‐defined copolymers. The thermal properties revealed a linear decrease in glass transition temperature for copolymers containing up to 39 wt % NonOx. Furthermore, the melting temperature of the copolymers containing 0 to 55 wt % PhOx linearly decreased most likely due to disturbance of the NonOx crystalline domains by incorporation of PhOx in the NonOx part of the copolymer. The surface energies of spincoated polymer films revealed a strong decrease in surface energy upon incorporation of NonOx in the copolymers due to strong phase separation between NonOx and PhOx allowing the NonOx chains to orient to the surface. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6433–6440, 2009     

Development and validation of a capillary electrophoresis method for the enantiomeric purity determination of SLV307, a basic potential antipsychotic compound

A capillary electrophoresis method for the enantiomeric purity determination of SLV307, a basic potential antipsychotic compound, has been developed and validated. It is shown that the presence of the eutomer in the sample solution may have a significant effect on the peak shape of the distomer, due to electrodispersion. The method is shown to give good performance with respect to the validation parameters specificity, linearity, accuracy, precision, determination limits, stability of solutions, and robustness of extraction.     

Crystal and molecular structure of rac(1R,5S,6S,7R)-1-oxy-7-benzoyl-5-methyl-8-azabicyclo-[4.3.0]nonane-4,9-dione,C16H17NO4 (perhydroindole)

The structure of the title compound (perhydroindole) was determined by X-rays, using CuK radiation (graphite-crystal monochromator,=1.54184 Å): T=290 K., C₁₆H₁₇NO₄,M _r =287.31 monoclinic, space groupC2/c,a= 14.471(1),b=6.169(2),c=32.065(2) Å,=92.192(6)V _c =2860,6 ų,Z=8,D inx=1.338 Mg m^–3, (CuK)=7.54 cm^–1. Final conventionalR-factor=0.048, (R _w =0.072) for 2513 unique reflections and 258 variables. The structure was solved usingMultan. The six-membered ring of the molecule is in the chair configuration. The molecules are connected by hydrogen bonds.