Oxitranyl-Β-aminovinyl ketones. 2. Synthesis of 3(2H)-furanones

The reaction of oxiranyl--dimethylaminovinyl ketones with secondary amines, hydrochloric, and hydrobromic acids leads to the formation of the corresponding 2-aminomethyl- and 2-halomethyl-3-(2H)-furanones.For Communication 1, see [1].Translated from Khimiii Geterotsiklicheskikh Soedinenii, No. 12, pp. 1600–1603, December, 1988.Original article submitted May 20, 1987.     

Synthesis and in vitro behavior of iron-crosslinked N-methyl and N-benzyl hydroxamated derivatives of alginic acid as controlled release carriers

N-methyl and N-benzyl hydroxylamines were synthetically conjugated to alginic acid to produce hydroxamated derivatives with different degrees of substitution. The new polymeric materials were used to form coordinate complexes with iron(III). The hydroxamated derivatives as well as their iron complexes were characterized using infrared spectroscopy and differential scanning calorimetry.Phenobarbitone-loaded and blank beads were prepared utilizing the new iron-crosslinked hydroxamated polymers and evaluated with respect to their ability to control drug release, as well as their iron leaching properties.The iron-crosslinked polymeric composites proved capable of encapsulating the model drug and sustaining its release in the dissolution media, the release profiles were sensitive to the type and degree of substitution.     

Synthesis and Antimicrobial Activity of Novel Furothienoquinoxalines,Pyranothienoquinoxalines and Pyrimidopyranothienoquinoxalines

The reaction of ethyl‐3‐mercaptoquinoxaline‐2‐carboxylate with phenacyl bromide, ethyl chloroacetate, chloroacetonitrile or chloroacetone furnished the corresponding 3‐hydroxy thieno[2,3‐b]quinoxaline. 2‐Cyano‐3‐hydroxythieno[2,3‐b]quinoxaline and 2‐acetyl‐3‐hydroxythieno[2,3‐b]quinoxa line were employed as precursors in the synthesis of some novel furo[2′,3′:4,5]thieno[2,3‐b]quinoxaline, pyrano[2′,3′:4,5]thieno[2,3‐b]quinoxaline and other heterocyclic systems fused with thieno[2,3‐b]quinoxalines. The antibacterial and antifungal activities of some the synthesised compounds were studied.     

Spectra and Structures of Silicon-Containing Compounds. XXIV.* Raman and Infrared Spectra,r 0 Structural Parameters,Vibrational Assignment,Barriers to Internal Rotation,and Ab Initio Calculations of Ethylsilane

The infrared (3200 to 400 cm^–1) and Raman (3200 to 20 cm^–1) spectra of gaseous and solid ethylsilane, CH₃CH₂SiH₃, have been recorded. Additionally, the Raman spectrum of the liquid has been obtained with quantitative depolarization values. The SiH₃ torsional mode has been observed as sum and difference bands with the silicon-hydrogen stretching vibration. Utilizing the torsional fundamental frequency of 132 cm^–1 the threefold periodic barrier of 590 cm^–1 (7.06 kJ/mol) has been obtained. Utilizing the frequencies of the silicon-hydrogen stretches, Si-H bond distances of 1.485 and 1.484 Å have been obtained for the bonds gauche and trans to the methyl group, respectively. Using previously reported rotational constants from seven different isotopomers, the r ₀ parameters have been calculated and are compared to the corresponding r _s parameters. A complete vibrational assignment is proposed that is consistent with the predicted frequencies utilizing the force constants from ab initio MP2/6-31G(d) calculations. Both the infrared intensities as well as the Raman activities and depolarization values have been obtained from the ab initio calculations. Complete equilibrium geometries have been determined by ab initio calculations employing the 6-31G(d), 6-311 + G(d,p), and 6-311+G(2d,2p) basis sets at levels of restricted Hartree–Fock (RHF) and/or Moller–Plesset (MP) to second order. The results are discussed and the theoretical values are compared to the experimental values when appropriate.     

Preparation of sub-micrometer silica shells using poly(1-methylpyrrol-2-ylsquaraine)

Poly(1-methylpyrrol-2-ylsquaraine) precipitates from reaction solution as uniformly spherical particles with a diameter of 1.3 microm. Upon heating, the particles reduce in diameter until extinction at approximately 630 degrees C. Treatment of the particles with 9:1 tetraethoxysilane:ethanol solution, and subsequent hydrolysis in dilute acid, results in a polymer core-silica shell structure. Removal of the core, upon heating to 660 degrees C, results in an amorphous silica shell with a diameter half that of the initial template sphere. It has been found that the silica shells produced by this method are able to encapsulate organic dyes upon soaking of the shells in chloroform solutions of the dyes, and further washings with fresh chloroform did not remove the dyes. The production of crystalline titanium dioxide shells was also achieved through the use of the polysquaraine particles as a spherical template.     

Microwaves in organic synthesis: Facile synthesis of biologically active pyridazinone and iminopyridazine derivatives

Condensation of Wittig reagents 1a,b with arylhydrazones 2a,b by conventional and by microwave heating techniques furnished the corresponding pyridazines 3a‐e . The arylhydrazones 7a,b were allowed to react with 1a,b under the same conditions to produce the pyridazinones 10a,b and iminopyridazines 11a,b respectively. On the other hand, the arylhydrazones 12a‐c reacted with 1a to afford the pyridazinones 13a‐c . Treatment of 3b with dimethylformamide dimethyl acetal (DMFDMA) produced the adduct 15 . The utility of microwave heating technique led to the reduction of the reaction times to few minutes and to the improvement of the yields of the products. The in vitro biological activity of some newly prepared compounds against four types of fungi was studied.     

Synthesis of some novel 2,6‐disubstituted pyridazin‐3‐ones as TMC120 analogues

Different analogues of TMC120 derived from pyridazin‐3(2H)‐one rings were synthesized by coupling of 3,6‐dichloropyridazine with arylacetonitriles, phenols and/or aniline derivative followed by hydrolysis and alkylation with different benzyl bromide derivatives.     

Simultaneous determination of hyoscine butylbromide and ketoprofen in pharmaceutical preparations by spectrophotometric and liquid chromatographic methods

A binary mixture of hyoscine butylbromide and ketoprofen was determined by 4 different methods. The first involved determination of hyoscine butylbromide and ketoprofen using the ratio-spectra first-derivative spectrophotometric technique at 211 and 234 nm over the concentration ranges of 2-14 and 5-45 microg/mL with mean accuracies 99.84 +/-0.92 and 99.98+/- 0.64%, respectively. The second method utilized second-derivative spectrophotometry over the concentration ranges of 2-14 and 5-35 microg/mL with mean accuracies 99.32+/- 1.06 and 99.55+/-1.15%, respectively. The third method was based on the resolution of the 2 components by bivariate calibration depending on a simple and rapid mathematical algorithm and quantitative evaluation of the absorbances at 206 and 254 nm over concentration ranges of 2-16 and 5-35 microg/mL; mean accuracies of 100.21+/-1.30 and 100.19 +/-1.07% were obtained for hyoscine butylbromide and ketoprofen, respectively. The fourth method was reversed-phase liquid chromatography using 0.05 M ammonium dihydrogen phosphate-acetonitrile-methanol (20 + 30 + 6, v/v) as the mobile phase with ultraviolet detection at 220 nm over concentration ranges of 1-90 and 5-70 microg/mL; mean accuracies were 99.92+/-1.02 and 99.61+/- 0.98%, respectively. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical preparations. The methods retained their accuracy and precision when the standard addition technique was applied. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the manufacturer's method.     

On the refracted patterns produced by liquid vortices

A theoretical analysis of the refracted shadows produced by steady and time-decaying liquid vortices under uniform illumination from above is given in this article. An expression for the induced shadow intensity is derived and found to be a function of the vortex’s free surface profile, i.e., function of the static pressure distribution. The patterns for different focusing depth are given and compared with previous visualization results from the literature. The phenomenon is examined and illustrated as a bench mark case by using both steady and time-decaying algebraic vortex models. However, this study can be extended to check the feasibility of recovering the main flow properties by analyzing the luminous image intensity of the refracted patterns. The present analysis is valid only when the swirl velocity is order of magnitude higher than the meridional flow components and the vorticity is concentrated within the core region and of intense conditions.     

Nano-Co3O4-catalyzed microwave-assisted one-pot synthesis of some seleno [2 , 3-b ] pyridine/quinoline derivatives

For the efficient synthesis of transition-metal cobalt oxide nanoparticles (Co₃O₄ NPs) without using any costly and toxic solvent or complicated equipment, the co-precipitation method was used in this work. Using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), UV–Vis spectrophotometry, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), the prepared Co₃O₄ NPs were characterized and identified. The influence of prepared Co₃O₄ NPs on the developmental synthesis of some selenopyridine/quinoline derivatives under different microwave irradiation powers and irradiation times was investigated via click (reaction) chemistry. The reusable Co₃O₄ nanoparticles have high catalytic activity under microwave irradiation for the synthesis of organoselenium compounds with higher yields (>?90%), milder reaction conditions and shorter time without significantly decreasing the reaction rates and yields.