Key Engineering Materials Vol. 800

Abstract: Asymmetric induction caused by 4-substituted oxazolidin-2-one type auxiliaries in reactions of N-cinnamoyloxazolidinones with phenylmagnesium bromide in the presence of CuBr×SMe₂ catalyst were examined. Resulted 3,3-diarypropionic acid derivatives were converted into 6-hydroxy-4-phenyldihydrocoumarine via demethylation and subsequent pyrane ring closure. Hydroarylation of N-cinnamoyloxazolidinones with 1,3,5-trimethoxybenzene was performed affording 3,3-diarypropionic acid derivatives.

Abstract: Nitrofurantoin was crystallized from multiple mixtures of water and organic solvents with and without additives to try to find and identify factors affecting phase obtained in crystallization and provide possible information on crystallization control. Obtained crystals were identified with powder X-ray diffractometry. Crystallization control possibilities were evaluated by using polymer additives and crystallization additives, by also using quantum chemical calculations to investigate the association of nitrofurantoin and additive molecules and calculate Gibbs energy of association.

Abstract: The growing demand for functionality of implants is necessary to cater for the growing elderly population in need of repair for damaged or diseased tissues and organs. Radiofrequency magnetron sputtered crystalline hydroxyapatite thin films with preferred crystal orientation on polished titanium substrates were produced without additional substrate heating. No hydroxyl absorption bands were detected in hydroxyapatite thin films even after the addition of water vapour during the sputtering process or hydrothermal post-treatment of the films.

Abstract: The protonation process of tyrosine kinase inhibitor lapatinib was studied by means of ¹HNMR and UV/Vis spectroscopy joint with the theoretical calculations at DFT and semi-empirical levels. DFT/M06-2X geometries were used to describe and compare the different cationic forms of lapatinib, while ZINDO/S-CI method performed on those geometries allowed for the interpretation of experimental UV/Vis spectra of lapatinib at various pH. We found that at low pH two different dicationic forms (N2N1 and N1N3) of lapatinib were present in ethanol and DMSO-d₆ solutions. The first protonation, however, occurred on the aliphatic N1 in DMSO-d₆, while in ethanol solutions most probably the quinazoline nitrogen atom N2 was also protonated.

Abstract: Hydroxyapatite (HAp) has shown the ability to store a charge induced by electrical polarization a method potential for improved bone ingrowth. In this work electrical polarization was carried out on HAp ceramics with three different microstructures, obtained at three different sintering temperatures. Microstructure of the sintered HAp was evaluated from density measurements and SEM observations. Sintered HAp tablets were electrically polarized in an electric field of 5 kV/cm at 400 °C for 1h. Surface charges investigated by thermally stimulated depolarization current measurements showed 104,8 μC/cm² for denser tablets, while charge density of 22,8 μC/cm² was obtained for less dense tablets.

Abstract: Few derivatives of 3-arylmethyl-4-hydroxycoumarin and 4-aryl-3,4-dihydrocoumarin as potential free radical scavengers were synthesized. The antiradical activity of these compounds was measured according to 1,1-diphenyl-2-picrylhidrazyl and galvinoxyl tests. It strongly depends on phenol-type substituent attached to the coumarin skeleton, nevertheless the chromen-2-one scaffold by itself plays an important role for the antiradical activity.

Abstract: Oxazolidinones are an important class of heterocyclic compounds that are used as chiral auxiliaries in asymmetric synthesis and as biologically active pharmaceutical agents. Moreover, carbohydrates are ideal scaffolds to generate libraries of bioactive compounds due the presence of defined configuration. We report here asymmetric alkylation studies on N-derivatized glucose-and allose-based spirooxazolidinones which do act as chiral auxiliaries.

Abstract: Copper (II) and indium (III) triflate catalyzes the Rupe rearrangement of propargylic alcohols in liquid sulfur dioxide as the reaction medium. 1-Ethynylcyclohexanol and 1-(phenylethynyl) cyclohexan-1-ol were used as the model substrates and the expected 1-(cyclohex-1-en-1-yl) ethanone and 1-(cyclohex-1-en-1-yl)-2-phenylethanone were obtained in average yields.

Abstract: The largest comparison of analytical techniques, useful for calcium phosphates, has been conducted, presenting recommendations for quality control and research of calcium phosphates. Results from three classical quantification methods (gravimetry, titramety, photometry) and three instrumental measurement methods (XRF, FAAS ICP-OES) are reported to determine the most accurate, fastest and cheapest analysis method. Remarks are given for increasing the accuracy for each method and corrections made for adsorbed water. For routine analysis, a recommendation is given to ICP-OES for a fast analysis, together with a less frequent use of gravimetry to validate the results and provide a periodic cross-check.