Synthesis, antimycobacterial, antifungal and photosynthesis-inhibiting activity of chlorinated N-phenylpyrazine-2-carboxamides

A series of sixteen pyrazinamide analogues with the -CONH- linker connecting the pyrazine and benzene rings was synthesized by the condensation of chlorides of substituted pyrazinecarboxylic acids with ring-substituted (chlorine) anilines. The prepared compounds were characterized and evaluated for their antimycobacterial and antifungal activity, and for their ability to inhibit photosynthetic electron transport (PET). 6-Chloro-N-(4-chlorophenyl)pyrazine-2-carboxamide manifested the highest activity against Mycobacterium tuberculosis strain H37Rv (65% inhibition at 6.25 μg/mL). The highest antifungal effect against Trichophyton mentagrophytes, the most susceptible fungal strain tested, was found for 6-chloro-5-tert-butyl-N-(3,4-dichlorophenyl)pyrazine-2-carboxamide (MIC=62.5 μmol/L). 6-chloro-5-tert-butyl-N-(4-chlorophenyl)pyrazine-2-carboxamide showed the highest PET inhibition in spinach chloroplasts (Spinacia oleracea L.) chloroplasts (IC50=43.0 μmol/L). For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds as well as their structure-activity relationships are discussed.     

Efficient one-pot synthesis of cyclic β-enaminoamides by thermal Wolff rearrangement of cyclic 2-diazo-1,3-dicarbonyls and conversion to uracil derivatives

This paper describes simple and efficient approaches for the preparation of β-enaminoamides through thermal Wolff rearrangement of cyclic diazodicarbonyls followed by trapping with various amines. The synthesized β-enaminoamides were readily converted into uracil derivatives.     

Rhodium(II)-Catalyzed Dipolar Cycloaddition of Cyclic Diazodicarbonyl Compounds with α, β -Unsaturated Esters. Synthesis of Dihydrofurans

An efficient synthesis of dihydrofurans is achieved by rhodium-catalyzed dipolar cycloaddition of cyclic diazodicarbonyl compounds with α,β-unsaturated esters.     

Ca(OH)2-mediated efficient synthesis of 2-amino-5-hydroxy-4H-chromene derivatives with various substituents

A variety of novel 2-amino-5-hydroxy-4H-chromene derivatives with various substituents on the 4H-chromene ring were efficiently synthesized by one-pot reactions of substituted resorcinols and various 2-benzylidenemalononitriles in the presence of calcium hydroxide in methanol at room temperature. This simple method provided 2-amino-5-hydroxy-4H-chromenes with high yields under mild reaction conditions.     

Preparation of a biodegradable superabsorbent polymer and measurements of changes in absorption properties depending on the type of surface‐crosslinker

A superabsorbent polymer (SAP) is a special polymer material that can absorb up to 500 times its own weight of pure water, but has a problem that it does not biodegrade itself and cause environmental pollution. Therefore, we aim to prepare a biodegradable SAP by using biomass‐based IA. The SAP must be able to retain absorbed water and absorb water under a given pressure. We have carried out studies to improve the surface hardness of the SAP to enhance absorption of water under a given pressure by surface‐crosslinking. Four types of surface‐crosslinkers, ethylene glycol diglycidyl ether (EGDGE), ethylene carbonate (EC), 1,4‐butanediol (BD), or glycerol, were used. We confirmed the water absorption capacity of the SAP by measuring its centrifuge retention capacity (CRC) and absorbency under load (AUL). The structural characteristics of the SAP were confirmed by attenuated total reflection (ATR) and X‐ray photoelectron spectroscopy (XPS), and the surface characteristics were confirmed by scanning electron microscopy (SEM).     

Canonical labels for protein spots of proteomics maps

We consider the problem of canonical labeling for a class of maps, which include proteomics maps, which consist of a set of vertices or protein spots. If this problem is solved and followed, different laboratories studying proteomics maps will arrive at the same numbering of spots, which would facilitate comparisons of data from different sources. In addition, the proposed canonical numberings of protein spots would allow compiling a catalog of proteomics maps just as canonical labeling allows making catalogs graphs, or molecules, and other canonically labeled systems, which would make search for similar sets of maps very efficient. We approach the problem by modifying the algorithm of Jeffrey for graphical representation of DNA based on the chaos game. Graphical representation of DNA as a chaos game map has an important property in that this representation allows one to assign sequential labels to spots in a DNA map. We have modified the approach for sequential labeling of chaos game map representations to graphical representation of any tabular data, such as listing of (x, y) coordinates of protein spots of proteomics maps.     

Efficient Synthesis of Biologically Active (±)‐Confluentin and (±)‐Daurichromenic Acid

One‐step synthesis of biologically active (±)‐confluentin is described from commercially available orcinol with trans,trans‐farnesal in the presence of ethylenediamine diacetate as a catalyst. Further conversion of synthetic confluentin to highly potent anti‐HIV agent, (±)‐daurichromenic acid, is accomplished by formylation and oxidation in two steps.     

Synthesis of Spinochalcone B and Analogues

An efficient synthesis of spinochalcone B and its analogues is achieved from readily available 2H‐pyran.