Reaction of 5,6-diamino-1,3-dimethyluracil with arylideneacetones and arylidenecyclanones

The reaction of 5,6-diamino-1,3-dimethyluracil dihydrochloride with mono- and diarylideneacetones and with cyclohexanones give 2,4-disubstituted 1,7,9-triazaspiro[4,5]dec-1-ene-6,8,10-triones. It was found that arylidenecyclopentanones form only 5-azomethines with retention of the amino group at position 6 of the uracil ring.Kharkov State University, Kharkov 310077, Ukraine; e-mail: desenko@univer.kharkov.ua. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1230–1233, September, 1999.     

Interaction of esters of β-aroylacrylic acids with <Emphasis Type="Italic">o</Emphasis>-phenylenediamines and 1,2-diamino-4-phenylimidazole

3-Phenacylquinoxalin-2-ones were synthesized by the reaction of the ethyl esters of β-aroylacrylic acids with o-phenylenediamines, while interaction with 1,2-diamino-4-phenylimidazole gave ethyl 7-amino-2-aryl-5-phenyl-3,4-dihydroimidazolo[1,5-b]pyridazine-4-carboxylates. Their chemical properties have been investigated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1646–1654, November, 2007.     

Effects of Coumarinyl Schiff Bases against Phytopathogenic Fungi,the Soil-Beneficial Bacteria and Entomopathogenic Nematodes: Deeper Insight into the Mechanism of Action

Coumarin derivatives have been reported as strong antifungal agents against various phytopathogenic fungi. In this study, inhibitory effects of nine coumarinyl Schiff bases were evaluated against the plant pathogenic fungi (Fusarium oxysporum f. sp. lycopersici, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiourum). The compounds were demonstrated to be efficient antifungal agents against Macrophomina phaseolina. The results of molecular docking on the six enzymes related to the antifungal activity suggested that the tested compounds act against plant pathogenic fungi, inhibiting plant cell-wall-degrading enzymes such as endoglucanase I and pectinase. Neither compound exhibited inhibitory effects against two beneficial bacteria (Bacillus mycoides and Bradyrhizobium japonicum) and two entomopathogenic nematodes. However, compound 9 was lethal (46.25%) for nematode Heterorhabditis bacteriophora and showed an inhibitory effect against acetylcholinesterase (AChE) (31.45%), confirming the relationship between these two activities. Calculated toxicity and the pesticide-likeness study showed that compound 9 was the least lipophilic compound with the highest aquatic toxicity. A molecular docking study showed that compounds 9 and 8 bind directly to the active site of AChE. Coumarinyl Schiff bases are promising active components of plant protection products, safe for the environment, human health, and nontarget organisms.     

Synthesis and antioxidant activity of some new coumarinyl-1,3-thiazolidine-4-ones

A series of Schiff's bases (E)-N-2-aryliden-2-(4-methyl-2-oxo-2H-chromen-7-yloxy)acetohydrazides 2a-l and N-(2-(substituted phenyl)-4-oxo-thiazolidin-3-yl)-2-(4-methyl-2-oxo-2H-chromen-7-yloxy)acetamides 3a-l were synthesized and evaluated for their antioxidant activity by the phosphomolybdenum method. Most of the Schiff's bases and thiazolidine-4-ones bearing two hydroxyl groups on the phenyl ring showed excellent antioxidant activity in comparison with ascorbic acid. Preliminary investigation on cytotoxic and antifungal activity was done on some representative samples.     

Photochemical properties of mixed-metal supramolecular complexes

We have prepared a series of mixed-metal trimetallic complexes of the form {[(bpy)₂Ru(BL)]₂MCl₂}ⁿ⁺(bpy 2,2′-bipyridine; BL 2,3-bis(2-pyridyl)pyrazine (dpp), 2,3-bis(2-pyridyl)quinoxaline (dpq) or 2,3-bis(2-pyridyl)-benzoquinozaline (dpb); M Ir(III), Rh(III) or Os(II). This new class of trimetallic complexes can be prepared with a good yield, often as high as 95%, using our building block strategy. The central rhodium and iridium fragments of these trimetallic, namely [M(BL)₂Cl₂]⁺, have been shown in our laboratory to be capable of delivering multiple electrons, “stored” on the bridging ligand π* orbitals, to a substrate as they functioned as electrocatalysts for the reduction of carbon dioxide to formate. The two terminal ruthenium metals are good light absorbers designed to give rise to photochemical activity. These bichromophoric systems should be capable of absorbing two photons of light, each giving rise to a desired photochemical reaction, namely excited-state electron transfer. Thus these systems form the basis of a molecular device for photoinitiated electron collection. The properties of these supramolecular complexes have been tuned by variation in the central metal and bridging ligand. Comparison of this array of nine complexes is described herein.     

IR Transmittance of Si/SiO2/Si3N4/Si Insular Structures Formed by Selective Laser Annealing

Journal of Applied Spectroscopy - Periodic Si/SiO2/Si3N4/Si structures with an insular surface layer were formed by selective laser annealing. A study by Fourier infrared spectrometry in the range...     

Synthesis of aromatic pyrazolo[4,5-b]pyridine derivatives

Cyclocondensation of chalcones with 5-amino-3-methyl-1-phenylpyrazole leads to the formation of 2,4-diaryl-5-methyl-7-phenyl-3,4-dihydropyrazolo-[4,5-b]pyridines, which undergo aromatization upon treatment with N-bromosuccinimide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1247–1251, September, 1987.     

Monitoring the Air Influence on Cement–Lime Mortar Hydration Using Low-Field Nuclear Magnetic Resonance Relaxometry

In the present study, we investigate the relationship between the nuclear magnetic resonance relaxation rate and the hydration time in two types of masonry cement-lime mortar. The studies are performed with the mortars both in an enclosed and a standard atmosphere to monitor the air influence on cement-lime mortar hydration and setting. The constituents of the investigated mortar samples are: cement, slaked lime, sand and water. They were mixed to achieve a flow spread of 10?cm. These types of mortars are usually suitable for historical masonry maintenance, but they can also be used for modern buildings, or even for concrete structures coatings to prevent concrete carbonation. All nuclear magnetic resonance relaxation experiments were performed at 20?°C using a low-field nuclear magnetic resonance instrument operable at 20?MHz proton resonance frequency. A slowing down of the hydration kinetics is demonstrated for the samples kept in closed atmosphere conditions. The results contribute to the understanding of cement–lime mortar hydration, carbonation and setting under closed atmosphere conditions.