Method for the solid-phase parallel synthesis of a 6-alkylamino-2-(functionalized-aminomethyl)-2H-1-benzopyran Library

A 2000-member library of benzopyran analogues was prepared by using a solid-phase synthesis protocol. Polymer-bound 6-alkylaminobenzopyrans 7 were synthesized as part of a first generation diversification step by employing reactions of a variety of alkyl halides with the amine 6. Transformations of the resin-bound intermediates 8 formed in this manner by reactions with acid halides, sulfonyl chlorides, and isocyanates leads to introduction of the second level of diversification found in the series of 6-alkylamino-2-(functionalized-aminomethyl)-2-methyl-2H-1-benzopyran analogues 11 and 12.     

Synthesis and nonlinear optical properties of novel Y‐type polyurethane containing tricyanovinylthiazole with enhanced thermal stability of second harmonic generation

A novel Y‐type poly[iminocarbonyloxyethyl‐5‐methyl‐4‐{2‐thiazolylazo‐4‐(1,2,2‐tricyanovinyl)}resorcinoxyethyloxycarbonylimino‐(3,3′‐dimethoxy‐4,4′‐biphenylene)] 4 containing 5‐methyl‐4‐{5‐(1,2,2‐tricyanovinyl)‐2‐thiazolylazo}resorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 4 is soluble in common organic solvents such as acetone and N,N‐dimethylformamide. It showed a thermal stability up to 250 °C in thermogravimetric analysis thermogram and the glass‐transition temperature (T_g) obtained from differential scanning calorimetry thermogram was around 118 °C. The second harmonic generation coefficient (d₃₃) of poled polymer films at 1560 nm fundamental wavelength was around 8.43 × 10^?9 esu. The dipole alignment exhibited a thermal stability even at 12 °C higher than T_g, and there was no SHG decay below 130 °C due to the partial main‐chain character of the polymer structure, which is acceptable for NLO device applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1166–1172, 2010     

An Efficient Synthesis of 2,8-Diazabicyclo[4.3.0]-nonane Derivatives via Intramolecular Cyclization Reaction

Novel 5-functionalized-2,8-diazabicyclo[4.3.0]nonane derivatives 5 were synthesized from epoxide 1 through 4 steps in 46.7～52.6% yield.     

Design, Development and Evaluation of Monovinyl Acrylates Characterized by Secondary Functionalities as Reactive Diluents to Diacrylates

This study focuses on the design and development of novel monovinylic (meth)acrylate monomers with enhanced polymerization kinetics and the evaluation of their performance as reactive diluents in diacrylate systems. Novel (meth)acrylic monomers characterized by several new secondary functionalities are developed in this study and are shown to exhibit reactivities 10-70 fold greater than traditional monoacrylates such as hexyl acrylate. These monomers were designed based on our understanding of interactions between monomer structure, polymerizations kinetics, and polymer properties. Performance of these monovinyl monomers as reactive diluents is also investigated in this study. Copolymerization of these monomers with diacrylates enhanced both the reactivity and the mechanical properties of the diacrylate system. Specifically, while copolymerization of a diacrylate system with traditional monoacrylates such as hexyl acrylate decreases the overall reactivity of the system, its copolymerization with the novel monomers led to comonomer mixtures, that were 30-50% more reactive than either of the individual components, with initial polymerization rates increased by as much as 2 times the more reactive component. Further, the copolymerization of these novel monovinyl systems with diacrylates also enabled formation of polymers with enhanced mechanical properties over the corresponding diacrylates including a more homogeneous network structure as indicated by a glass transition temperature that was narrowed by up to 55 % while increasing the glass transition temperature by as much as 10°C.     

An efficient conversion of nitroaromatics and aromatic amines to tertiary amines in one-pot way

Reductive alkylation and reductive methylation of aromatic primary amines with carbonyls and 37% formaldehyde using decaborane in one-pot way gave the corresponding tertiary amines in high yields. The reaction condition was extended for the reduction of nitroaromatic using decaborane and Pd/C followed by the reductive alkylation and reductive methylation using decaborane to give the corresponding tertiary amines in high yields.     

Study on air pollution monitoring in Korea using low volume air sampler by instrumental neutron activation analysis

The aim of this research was to enhance the use of nuclear analytical techniques for air pollution studies and to study the feasibility of the use of instrumental neutron activation analysis (INAA) as a routine monitoring tool to reveal environmental pollution sources. For the collection of air particulate samples, the Gent stacked filter unit, low volume sampler with Nucleopore membrane filters were used. Trace elements in samples collected at two suburban residential sites, Taejon and Wonju city in the Republic of Korea, were analyzed by INAA. Variations of the elemental concentrations were measured monthly and the enrichment factors were calculated for the fine (<2 μm EAD) and coarse size (2–10 μm EAD) fractions. The analytical data were treated statistically to estimate the relationship between the two variables, the concentrations of elements and the total suspended particulate matter. The results were used to describe the emission source and their correlation.