• Journal of Forest and Environmental Science
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• v.12 no.1
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• pp.37-44
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• 1996

Two dilignols composed of ${\beta}$-O-4 structure, a important substructure compound in lignin, was synthesized in high yield in a series of the synthetic studies of lignin model compounds. The dimers were identified with $^1H$ and $^{13}C$-NMR and Mass spectroscopy. The important compound of among them, the final synthetic compound [IV].is called 1-(3,4-dimethoxyphenyl)-2-(2'-methoxy-4'-hydroxymethylphenoxy)-propanediol-l,3. This dimeric lignin model compounds should be usefull for the studies of lignin reactions such as pulping, bleaching, pyrolysis, hydrogenolysis, oxidation, reduction, biodegradation, and chemical utilization.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.199-203
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• 2011

The title one-dimensional hydrogen-bonded coordination compound $[Cu^{II}(C_{13}H_{17}N_3OBr)(C_8H_5O_4)]{\cdot}2H_2O.CH_3OH$ has been synthesized and characterized by single crystal X-ray diffraction study. The monomeric unit contains a square-planar $Cu^{II}$ centre. The four coordination sites are occupied by a tridentate anionic Schiff base ligand (4-bromo-2-[(2-piperazin-1-yl-ethylimino)-methyl]-phenol) which furnishes an $N_2O$-donor set, with the fourth position being occupied by the oxygen atom of an adjacent terephthalate unit. Two adjacent neutral molecules are linked through intermolecular N-H---O and O-H---N hydrogen bonds and generate a dimeric pair. Each dimeric pair is connected with each other via discrete water and methanol molecules by hydrogen bonding to form a one-dimensional supramolecular network.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.970-975
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• 1998

Eighty percent of acetone extract were isolated from the leaves of Korean Oolong tea using Sephadex LH-20, MCI-gel, Fuji gel. The compound reacted the red and the blue with anisaldehyde and $FeCl_3$, respectively. Instrumental analysis of the derivatives of this compound showed that the chemical structure was decided to $epicatechin-(4{\beta}{\rightarrow}8)-epigallocatechin-3-O-gallate$ as a kind of dimeric proanthocyanidine, that bound with -(-)epicatechin and -(-)epigallocatechin-3-O-gallate, at the upper and the lower, respectively. Considering inhibition effect on xanthin oxidase by 62% levels at $50{\;}{\mu}mole$, this compound showed a possibility to be used as a new material for functional food.

• Toxicological Research
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• v.17
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• pp.105-108
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• 2001

Several marine toxins with macrolide structure have been found to act on actin. One of these toxins is mycalolide B isolated from the genus Mycale. This compound belongs to macrolide antibiotics and consists of tris-oxazole with strong cytotoxic activity ($IC_{50}$: 10-50 nM for growth of L1210 murine leukemia cells). This compound was found to be an actin-depolymerizing agent with the mode of action distinct from that of the known actin inhibitor, cytochalasin D. Tolytoxin, a macrolide isolated from cyano-bacteria with similar chemical structure to mycalolide B, seems to have similar effect. Another macrolide compound, aplyronine A, showed the effects similar to those of mycalolide B. Although bistheonellide A, a dimeric macrolide, did not show a severing effect, it de polymerized F-actin and sequestered G-actin by forming 1 : 2 complex with G-actins. Swinholide A has a structure and effects similar to those of bistheonel-lide A. In conclusion, mycalolide B, tolytoxin, aplyronine A, bistheonellide A and swinholide A are the members of "actin de polymerizing macrolide" the mechanism of which is different from that of cytochalasin D.halasin D.

• BMB Reports
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• v.42 no.6
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• pp.387-392
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• 2009

Here, we report the first biochemical and structural characterization of the hypothetical protein HP0902 from Helicobacter pylori, in terms of structural genomics. Gel-permeation chromatography and dynamic light scattering indicated that the protein behaves as a dimer in solution. Circular dichroism spectroscopy showed that HP0902 primarily adopts a $\beta$-structure and the protein was highly thermostable with a denaturing temperature higher than $70^{\circ}C$. Finally, the backbone NMR assignments were obtained on the [$^{13}C,^{15}N$]HP0902 and the secondary structure was determined using the chemical shift data. Additionally, the local flexibility was assessed via a heteronuclear $^1H-^{15}N$ steady state NOE experiment. The results revealed that HP0902 would adopt a compactly folded, all-$\beta$ topology with 11 $\beta$-strands. All of the results clearly support the notion that HP0902 belongs to the cupin superfamily of proteins.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1113-1117
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• 2009

The one-dimensional coordination polymers, $[Cu^{II}(L)(NO_3)_2]_n$ (1) and {$[Cu^{II}(L)(NO_3)]{\cdot}2H_2O}_{2n} (2), were synthesized from $Cu(NO_3)_2{\cdot}3H_2O$ and 2-[(pyridin-3-ylmethyl)amino]ethanol (L, PMAE) in methanol by controlling the molar ratio of copper(II) salt. Copper(II) ion in 1 has one pyridine group of PMAE whose an aminoethanol group coordinates adjacent copper(II) ion. As the pyridine group is bonded to neighboring copper(II) ion, 1 becomes a one-dimensional chain. Contrary to 1, the structure of 2 shows that the oxygen atom of ethoxide group is bridged between two copper(II) ions, which forms a dinuclear complex. Additionally, the pyridine group of PMAE included one dinuclear unit is coordinated to the other dimeric one each other, which leads to a one-dimensional polymer. Due to the structural differences, 1 exhibits weak antiferromagnetic interaction, while 2 shows strong antiferromagnetic interaction. Due to direct spin exchange via oxygen of PMAE 2 has a much strong spin coupling than 1.

• Journal of Photoscience
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• v.9 no.2
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• pp.347-349
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• 2002

Synthetic zinc chlorins possessing a hydrophylic polyoxyethylene chain at the 17 -position were prepared. An amphiphilic zinc chlorin possessing a single chIorin moiety showed absorption maxima at 675 nm in an aqueous medium, indicating that the zinc chIorin did not form large aggregates but a dimeric structure. In contrast, amphiphilic zinc chlorin dyads in which two zinc chlorin moieties were connected with a hydrophilic polyoxyethylene linkage showed red-shifted absorption band around 720-740 nm in an aqueous medium. The result indicated that the amphiphilic zinc chlorin dyad self-aggregated to form chlorosome-like oligomer.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.106-111
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• 2001

A ${\beta}-galactosidase$ gene of Bifidobacterium adolescentis Int57 (INT57) was cloned using the shotgun method. The sequence of the ${\beta}-galactosidase$ gene existing in the sequenced 3,260-bp fragment showed higher than 40% homology with other bacterial ${\beta}-galactosidase$ genes. The expression in Escherichia coli suggested that the ${\beta}-galactosidase$ might have a monomeric, dimeric, or tetrameric protein structure. This is probably the first peer-reviewed sequence analysis of the ${\beta}-galactosidase$ gene of the genus Bifidobacterium.

• Natural Product Sciences
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• v.8 no.3
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• pp.108-110
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• 2002

A new ardimerin (1) was isolated from the herb of Ardisia japonica. Its structure was determined by the elucidation of spectroscopic data and a chemical transformation. Compound (1) showed potent radical scavenging effect on DPPH radical $(IC_{50},\;0.32\;{\m}M)$.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3382-3388
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• 2011

Reaction of barbituric acid (BA), 1,3-dimethyl barbituric acid (DMBA) and 2-thiobarbituric acid (TBA) with cyanogen bromide and aldehydes in the presence of L-(+)-tartaric acid afforded a new route for the synthesis of stable heterocyclic 5-aryl-1H,1'H-spiro[furo[2,3-d]pyrimidine-6,5'-pyrimidine]2,2',4,4',6'(3H,3'H,5H)-pentaones which is a dimeric form of barbiturate (uracil and thiouracil derivative). In the reaction of 1,3-diethyl thiobarbituric acid (DETBA) the Knoevenagel condensation and then Michael adducts were obtained under the same condition. Structure elucidation is carried out by $^1H$ NMR, $^{13}C$ NMR, FT-IR and Mass analyses. Mechanism of the formation is discussed.