Four tetramethyl 4,4′-(ethane-1,2-diylidene)bis[1-R-5-oxo-4,5-dihydro-1H-pyrrole-2,3-dicarboxylate] compounds, denoted class (1), are a series of conjugated buta-1,3-dienes substituted with a heterocyclic group. The compounds can be used as dyes and pigments due to their long-range conjugated systems. Four structures were studied using ¹H NMR, ¹³C NMR and mass spectroscopy, viz. with R = 2,4,6-trimethylphenyl, (1a), R = cyclohexyl, (1b), R = tert-butyl, (1c), and R = isopropyl, (1d). A detailed discussion is presented regarding the characteristics of the three-dimensional structures based on NMR analysis and the X-ray crystal structure of (1a), namely tetramethyl 4,4′-(ethane-1,2-diylidene)bis[5-oxo-1-(2,4,6-trimethylphenyl)-4,5-dihydro-1H-pyrrole-2,3-dicarboxylate], C₃₆H₃₆N₂O₁₀. The conjugation plane and stability were also studied via quantum chemical calculations.

Matrilysin is an ideal biological target to develop novel inhibitors because it is overexpressed in malignant tumour cells. A series of 3,9-diazatetraasteranes was designed as inhibitors of matrilysin, which was an ideal biological target because it is responsible for aggressive malignant phenotypes and poor prognoses implicated in many cancers. Docking simulation supported the initial pharmacophore hypothesis and suggested a common interaction mechanism of 3,9-diazatetraasteranes with the catalytic site of matrilysin. The 3,9-diazatetraasteranes were synthesized by the photocyclization of 4-aryl-1,4-dihydropyridines, and their structures were determined using ¹H NMR, ¹³C NMR and MS. The inhibitory activities of these compounds on matrilysin were investigated in vitro using an MTT assay in A549 (small cell lung cancer) cells. The results show that the 3,9-diazatetraasteranes can inhibit the growth of A549 tumour cells. The best IC₅₀ value is approximately 50 μm. This result indicates that 3,9-diazatetraasteranes will be useful pharmacological tools for the investigation of matrilysin inhibitors.

Transformation of N-alkylated anilines to N-aryloxamates was studied using ethyl 2-diazoacetoacetate as an alkylating agent and dirhodium tetraacetate (Rh₂(OAc)₄) as the catalyst. The general applicability of the reaction as a synthetic method for N-aryloxamates was studied with a number of substituted N-alkylated anilines. The results revealed that the oxamate was formed by a radical reaction with molecular O₂ and Rh₂(OAc)₄ as initiator.

The 4-aryl-1,4-dihydropyrazines were prepared via the cyclization of N,N-bisalkylated anilines with ammonium acetate. These reactions were aided by improvements in the synthesis of N,N-bisalkylated anilines which were alkylated with anilines using ethyl 2-diazo acetoacetate in a reaction catalyzed by rhodium acetate in the absence of oxygen. A possible mechanistic route is postulated on the basis of the isolation of the N-alkylation intermediates, which were determined to be N-aryloxamates by ¹H NMR data and X-ray diffraction.

A simple and convenient method for the synthesis of 1,4-diazabutadienes (=N,N′-ethane-1,2-diylidenebis[amines]) by grinding glyoxal (=ethanedial) or an α-diketone and anilines (=benzenamines) in the presence of TsOH in a mortar with a pestle is described. By this way, 1,4-diazabutadienes were obtained in good to excellent yields.

A series of N-aryl-2-arylthioacetamide derivatives (2–4) designed as non-nucleoside reverse transcriptase inhibitors was synthesized and evaluated for their inhibitory activity against HIV-1 (IIIB) replication in MT-4 cell cultures. The compounds 2–4 were performed by the reaction of thiols and 2-chloro-N-substituted-acetamides and active in the lower micromolar concentration (1.25–20.83 μm). The studies of structure–activity relationship suggested that 1H-benzo[d]imidazole ring at arylthio moiety strongly improved the anti-HIV activity and consistent with the experimental data. The results of molecular modeling and docking within the RT non-nucleoside binding site using AutoDock confirmed that the 3 series, similar to other non-nucleoside reverse transcriptase inhibitors such as N-(5-chloro-2-pyridinyl)-N’-[2-(4-ethoxy-3-fluoro-2-pyridinyl)ethyl]-thiourea (PETT), was assumed in a butterfly-like conformation and helped to rationalize some SARs and the biological activity data.

Lycium barbarum polysaccharide (LBP) was subjected to ultrasonic degradation under the controlled conditions, such as, temperature, irradiation time, initial pH value, and concentration of solution. The ultrasonic degradation of LBP was demonstrated by the changes of intrinsic viscosity. Viscometry was used to study the degradation behavior and a kinetic model was developed to estimate the degradation rate. The results showed that the degradation rate was reduced with the increase of solution concentration and pH, and increased with increase of temperature. The relationship between the number average molar mass (M_n) and intrinsic viscosities as interpreted using the Mark-Houwink equation suggested that LBP adopted a flexible coil conformation in aqueous solution. The activation energy of ultrasonic degradation of LBP is 26.5 kJ/mol, which indicates that the ultrasonic degradation is a convenient, time saving, and cost-efficient method for obtaining a desired molecular weight. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 509–513, 2010