X-Ray kinetic study of glassy crystal formation in adamantane derivatives: TTT curves and crystal size effect

Abstract

The kinetics of polymorphic solid-state transformation in mixed adamantane compounds (CN_1?x Cl _x ADM: x = 0 and x = 0.25) have been studied by X-ray scattering. The classical form of the time-temperature-transformation TTT curves has been directly observed for the first time for the ordering supercooled plastic phases. For both compounds a considerable effect of crystal size on the kinetics has been observed. For x = 0.25 it leads to a continuous transition from Avrami to nucleation behaviour. These observations help us to understand the factors controlling nucleation and growth as well as to establish better operating conditions in order to form a glassy crystal.     

Reaction between anthranilic acids, salicylaldehydes and isocyanides in water: an efficient synthesis of 2-{[2-(alkylimino)-1-benzofuran-3-yliden]amino}benzoic acids

A novel, one-pot and three-component reaction for the preparation of 2-{[2-(alkylimino)-1-benzofuran-3-yliden]amino}benzoic acids is described. Heating a mixture of an anthranilic acid, a salicylaldehyde, and an isocyanide in water affords the title compounds in good to excellent yields.     

On the Use of Depleted Uranium Dioxide as a Neutron Filter

A simple additive formula is given which, for neutron energies in the range 10^-4 < E<10 eV, permits calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-sections of a crystalline material as a function of its crystal constants and temperature. Computer codes PUO and SUO were developed to calculate the total attenuation of reactor neutrons through poly- and mono-crystalline samples, respectively. The codes were applied to calculate the total cross-section of polycrystalline uranium and thorium dioxides in the energy range from 4 meV to 1 eV. The obtained agreement between the calculated values and available experimental values justifies the applicability of the used formula and the computer codes. A feasibility study on using depleted polycrystalline uranium dioxide as a cold neutron filter and the single crystal as a thermal neutron filter is given. The optimum crystal parameters and thickness for efficiently transmitting the thermal reactor neutrons while strongly attenuating both fast neutrons and -rays accompanying the thermal ones is also given.     

Facile and rapid access to inosine puromycin analogues through the use of adenylate deaminase

To study the ribosomal peptidyl transfer, puromycin analogues are of interest in which adenine has been replaced by hypoxanthine. We synthesized inosine puromycin analogues from 3'-azidodeoxyadenosine derivatives using adenylate deaminase for the quantitative transformation of the N-heterocycle. The amino acid coupling was carried out under Staudinger-Vilarrasa conditions in 94% yield starting from the protected and in 82% using the unprotected azide, thus, in the presence of two hydroxyls and a lactam function.     

Facile preparation of highly stable and active hybrid palladium nanoparticles: effectual,reusable and heterogeneous catalyst for coupling reactions

Palladium nanoparticles were supported on a bed of Fe₃O₄@‐NH₂@Murexide using a simple and efficient method, and characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, scanning and transmission electron microscopies and inductively coupled plasma optical emission spectrometry. The catalytic system showed great efficiency in cross‐coupling reaction of aryl iodides and arylboronic acid and in Sonogashira cross‐coupling reaction in the green solvent EtOH–H₂O (1:1). The isolation and recovery of the catalyst were simple and facile and it could be used for several successive Suzuki–Miyaura coupling and Sonogashira cross‐coupling reactions. Copyright © 2016 John Wiley & Sons, Ltd.     

Efficient Ce(NO3)3 x 6H2O-catalyzed solvent-free synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Cerium(III) nitrate hexahydrate efficiently catalyzes the three-component Biginelli reaction under solvent-free conditions of an aldehyde, a beta-keto ester or beta-diketone and urea or thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones or -thiones in excellent yields.     

Rotational Energy Barrier of the Polarized Carbon–Carbon Double Bond in Quinophthalone

 A dynamic NMR effect is observed in the ¹³C NMR spectra of anhydrous quinophthalone (quinoline yellow) and its monohydrate in the vicinity of 47°C and 0°C, respectively, and is attributed to a restricted rotation around the polarized carbon–carbon double bond. The free energy of activation for this process in anhydrous quinophthalone and the monohydrate is 65±2 and 55±2 kJ · mol⁻¹, respectively, in CDCl₃.     

Synthesis, antibacterial and antifungal activities of 3-aryl-5-(pyridin-3-yl)-4,5-dihydropyrazole-1-carbothioamide derivatives

A new series of 3-aryl-5-(pyridin-3-yl)-1-thiocarbamoyl-2-pyrazoline derivatives (4a-j) were prepared by the reaction of azachalcons 3a-j with thiosemicarbazide in ethanolic sodium hydroxide. The structure of synthesized compounds were confirmed by ¹H NMR and Mass spectral data. Their antibacterial activities against Escherichia coli (CTP 7624), Staphylococcus aureus (ATCC 6538), Staphylococcus epidermidis (ATCC 12229), Pseudomonas aeruginosa (ATCC 9027), Bacillus subtilis (ATCC 1156) and Micrococcus luteus (ATCC 9341) were investigated. Antifungal activity of compounds against Candida albicans and Candida globrata were found to be inactive. Compounds 4a-j were also evaluated for antituberculosis activity against Mycobacterium tuberculosis H ₃₇ Rv (ATCC 27294) in BACTEC 12B using a broth microdilution assay and Microplate Alamar Blue Assay (MABA). The preliminary results showed that compounds 4e, 4d and 4g had 87%, 93% and 92% inhibitory effect respectively.     

Am(m)ines Make the Difference: Organoruthenium Am(m)ine Complexes and Their Chemistry in Anticancer Drug Development

With the aim of systematically studying fundamental structure–activity relationships as a basis for the development of Ru^II arene complexes (arene=p‐cymene or biphenyl) bearing mono‐, bi‐, or tridentate am(m)ine ligands as anticancer agents, a series of ammine, ethylenediamine, and diethylenetriamine complexes were prepared by different synthetic routes. Especially the synthesis of mono‐, di‐, and triammine complexes was found to be highly dependent on the reaction conditions, such as stoichiometry, temperature, and time. Hydrolysis and protein‐binding studies were performed to determine the reactivity of the compounds, and only those containing chlorido ligands undergo aquation or form protein adducts. These properties correlate well with in vitro tumor‐inhibiting potency of the compounds. The complexes were found to be active in anticancer assays when meeting the following criteria: stability in aqueous solution and low rates of hydrolysis and binding to proteins. Therefore, the complexes least reactive to proteins were found to be the most cytotoxic in cancer cells. In general, complexes with biphenyl as arene ligand inhibited the growth of tumor cells more effectively than the cymene analogues, consistent with the increase in lipophilicity. This study highlights the importance of finding a proper balance between reactivity and stability in the development of organometallic anticancer agents.