• Bulletin of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.1225-1231
• /
• 2013

A novel class of hyperbranched polyesters, HPpEP and HPmEP, were prepared via a facile one-pot polymerization of a phloroglucinol (as a $B_3$ monomer) with a phthaloyl dichloride (as an $A_2$ monomer) for replacing a problematic BPA developer in thermal printing system. The resulting polymers, HPpEP and HPmEP, had highly branched structures and met well the requirements for high performance developer materials such as colorlessness, easy and inexpensive synthesis, high thermal stability, etc. In addition, these polymers exhibited an efficient reaction with leuco dyes (ODB-2) for a coloring process by releasing protons from linear and terminal phenol groups of polymers when heated.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.1054-1056
• /
• 2009

We have demonstrated a one-pot three component coupling of an aldehydes, an amines, and triethyl phosphite using 1-benzyl-3-methyl imidazolium hydrogen sulphate [bnmim][][$HSO_{4}$] as an efficient catalyst. All the reactions proceed under solvent-free conditions at room temperature. This methodology afforded the corresponding $\alpha$-aminophosphonates in shorter reaction times with excellent yields.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.10
• /
• pp.1429-1432
• /
• 2003

A novel fused thiouracil containing a heterocyclic ring system, dipyrimidinopyridine (3), has been prepared through the cyclization of compound 2. Compound 2 was formed by the formylation of 6-amino-2-thiouracil 1, pyrazolopyrimidines 8-10 via the heating of 6-arylhydrazono-2-thiouracils 5-7, compound 11, using Vilsmeier reagent with compound 4, pyrazolylpyrimidine 12, indolodiazinopyrimidine 14 and pyridazinopyrimidine 15. Pyridazino-pyrimidine 15 was formed by the condensation of compound 4 with acetylacetone, isatin and benzyl, respectively.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.2
• /
• pp.585-589
• /
• 2013

Optically active N-benzyl-2-methyl-2H-benzo[b][1,4]oxazin-3(4H)-ones and N-benzyl-2-methyl-2H-benzo[b][1,4]thiazin-3(4H)-ones with potential synthetic and pharmacological interest were prepared via Smiles rearrangement in conventional as well as microwave irradiation conditions in one-pot from inexpensive (S)-2-chloropropionic acid. Most of the compounds displayed good inhibition against Gram positive bacteria and fungi in the antibiotic test.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.1
• /
• pp.119-121
• /
• 2004

A new and efficient synthesis of the novel bioactive bis(benzopyrano) fused dihydropyridines is described. The conventionally developed route is a two step multicomponent condensation reaction. This is latter modified by a one pot microwave (MW) assisted reaction using inorganic solid support via the arylidene derivative intermediate. With this environmentally benign approach, the reaction time is brought down from hours to minutes along with a yield enhancement. Furthermore, the role of different solid supports is studied and it is concluded that the acidic alumina is the best solid support for the present investigation.

• Macromolecular Research
• /
• v.8 no.4
• /
• pp.186-191
• /
• 2000

Clay-dispersed nanocomposites have been prepared by simple melt-mixing of three components, i.e. poly (styrene co-acrylonitrile) copolymer (SAN), poly ($\xi$-caprolactone ) (PCL), and an organophilic clay(Cloisite(R) 30A). In the present study, poly($\xi$-caprolactone) was added in the mixtures in order to facilitate the intercalation of SAN into the gallery of silicate layers, and the molecular weight effects of PCL on the dispersion of silicate layers were compared by changing the amount of added PCL. The degree of dispersion of 10-$\AA$-thick silicate layers of clay in the nanocomposites was investigated by using an X-ray diffractometer and a transmission electron microscope. It was found that PCL added in the mixture facilitate the intercalation of SAN copolymers into the galleries of silicate layers modified with an organic intercalant, resulting in the better dispersion of clay. It was, also, observed that the processing temperature influences the degree of clay dispersion.

• Journal of the Korean Ceramic Society
• /
• v.54 no.3
• /
• pp.257-260
• /
• 2017

In this work, we present a facile one-pot synthesis of a multilayer-structured platy alumina/few-layer graphene nanocomposite by planetary milling and hot pressing. The sintered composites have electrical conductivity exhibiting percolation behavior (threshold ~ 0.75 vol.%), which is much lower than graphene oxide/ceramic composites (> 3.0 vol.%). The conductivity data are well-described by the percolation theory, and the fitted exponent values are estimated to be 1.65 and 0.93 for t and q, respectively. The t and q values show conduction mechanisms intermediate between 2D- and 3D, which originates from quantum tunneling between nearest neighbored graphenes.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.1 no.2
• /
• pp.134-143
• /
• 1993

The trajectory planning for the manipulator installed on "the automatic pothole repair vehicle" is discussed and the final surface of the patched pot hole is simulated in this work. The relationship between the accumulation data of the mixture with and without the movement of the manipulator is identified to utilize the latter data for the calculation of the former one. Based on this relationship, the method to calculate the accumulation of the mixture when the manipulator changes the speed and the direction is also introduced. The trajectory is determined to make the final surface smooth under the condition that the pothole is cut to hexahedron before patching and only the spacing and the shifting of the manipulator is controllable. Final surface is simulated by the computer to prove the adequacy of the determined trajectory.

• Bulletin of the Korean Chemical Society
• /
• v.21 no.8
• /
• pp.797-800
• /
• 2000

The reaction of o-acylthiophenacyl chloride 5a with onc equivalent ofsodium azide in aqueous acetone at-10~ $-5^{\circ}C$ gave 2,9-dimethyl-6H,I3H-dibenzo[d,i][1,6]dithiecin-7,14-dione 7(10%),acyclic dimer 8(64%),and tri-mer 9 (8%). Dimer 8 and trimer 9 we re converted readily to 7 under the similar conditions at room temperature in yields of 72% and 53%,respectivel. Also, one pot synthesis of 7 (64%, 45%) from the reaction of 5a or 5b with two equivalents of sodium azide at room temperature was very successful.

• Journal of Integrative Natural Science
• /
• v.2 no.4
• /
• pp.285-288
• /
• 2009

A synthetic route for 12 metal thiocarboxylate complex, $Cd(SOCCH_3)_2Lut_2$ [Lut = 3,5-dimethylpyridine (lutidine)], were investigated for their potential to act as precursors for the formation of cadmium sulfide nanoparticles. $Cd(SOCCH_3)_2Lut_2$ were characterized by 1H-NMR spectroscopy. Thermal decomposition of $Cd(SOCCH_3)_2Lut_2$ is expected to undergo thiocarboxylic anhydride elimination to give stoichiometric cadmium sulfide nanoparticles and removes the organic supporting ligands cleanly. Prepared cadmium sulfide nanoparticles were characterized by fluorescence and UV-vis absorption spectroscopy and displayed an emission band at 500 nm with an excitation wavelength of 360 nm.