• Applied Biological Chemistry
• /
• v.37 no.1
• /
• pp.25-29
• /
• 1994

2-methyl-5(S)-hexanolide(1); the major component of pheromonal blend of the male carpenter bee was synthesized via Homer-Emmons reaction from Ethyl(S)-3-hydroxybutyrate(2a) which had been obtained by Baker's Yeast reduction in overall yield 39%.

• Parasites, Hosts and Diseases
• /
• v.43 no.3 s.135
• /
• pp.123-126
• /
• 2005

Each diastereomer of 10-thiophenyl- and 10-benzenesulfonyl-dihydroartemisinin was synthesized from artemisinin in three steps, and screened against chloroquine-resistance and chloroquine-sensitive Plasmodium falciparum. Three of the four tested compounds were found to be effective. Especially, 10$\beta$-benzenesulfonyl-dihy-droartemisinin showed stronger antimalarial activity than artemisinin.

• Journal of Applied Biological Chemistry
• /
• v.43 no.2
• /
• pp.101-103
• /
• 2000

The synthesis and resolution of ($\pm$)-10,11-dihydroxydibenzosuberenone 3, a potential pharmaceutical compound, is described. It was synthesized from the 5H-dibenzo[a,d]cycloheptene-5-one (dibenzosuberenone) 1, and converted to diastereomeric isomers using (R)-(+)-$\alpha$-methylbenzylamine. Optical resolution of ($\pm$)-10,11-dihydroxydibenzosuberenone 3 was possible by fractional recrystallization of the diastereomer formed in ethanol. The optical resolution of 10,11-dihydroxydibenzosuberenone through formation of its phosphoamidates 5 using the (R)-(+)-$\alpha$-methylbenzylamine was achieved. These compounds provided the optical rotation of [${\alpha}]=-64.3$ for (-)-10,11-dihydroxy-dibenzosuberenone and [${\alpha}]=+61.3$ for (+)-10,11-dihydroxydibenzosuberenone. The (-)- and (+)-enantiomers were prepared in five steps from dibenzosuberenone with overall yields of 11.66% and 9.38%, respectively.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1993.04a
• /
• pp.50-51
• /
• 1993

광학활성 물질의 분할은 화학공정에 있어서나 생명과학에 있어서 중요한 분야로, 특히 의약이나 농약등의 생리활성물질에 광학이성질체가 상당수 존재하고 있으며, 그중에서는 경상체간에 생리활성이 현저하게 다른 것이 상당수 존재한다. 이러한 광학활성 물질을 분리하는 방법으로는 크로마트그래피를 이용한 방법, Diastereomer를 이용하는 방법등이 있으나 본 연구에서는 고분자 착체막을 이용하여 경상체를 분리하고자 한다. 전이금속착체를 이용한 경상체의 분리는 주로 crown ether를 중심으로 이루어져 왔다. 즉 전이금속의 흡착력과 crown ether의 입체구조를 이용한 것이다. 그러나 이것은 액막에서나 가능한 것으로 고체막에서는 사용할 수 없다. 따라서 본연구에서는 아크릴 계통의 고분자 전이금속 착체막을 이용하여 아미노산 경상체간의 분리를 행하고자 한다. 즉 전이금속의 흡착력과 리간드의 입체구조를 이용하여 경상체를 분리하는 것이다.

• Bulletin of the Korean Chemical Society
• /
• v.17 no.11
• /
• pp.1031-1036
• /
• 1996

The synthesis and characterization of diastereomeric dodecanucleotides, d[GATCp(S)TCGAGATC], containing recognition sequence of the XhoI restriction endonuclease with a phosphorothioate internucleotidic linkage the cleavage site are described. Rp and Sp form of diastereomerically pure dinucleoside phosphorothioates d[Cp(S)T] were presynthesized and used for the addition to the growing oligonucleotide chain as a block. The stereochemistry of dinucleoside phosphorothioate was assigned by 31P NMR spectroscopy, enzyme digestion, and reverse-phase HPLC. XhoI restriction endonuclease cut only Rp diastereomer d[GATCp(S))TCGAGATC]. The rate of hydrolysis is slower than that of the unmodified dodecamer d[GATCTCGAGATC]. The phosphorothioate nucleotide is using for determination of the stereochemical course of the XhoI catalyzed reaction.

• YAKHAK HOEJI
• /
• v.38 no.5
• /
• pp.544-554
• /
• 1994

Pyrrolidine-2,3-dione derivative A was synthesized from oxalylation of chiral enamine Ba. The stereostructure of its major diastereomer $(A_{maj})$ was determined as octahydro-2,3-dioxo-6aS-hyd roxy-1-(1S-methoxycarbonyl-2-phenylethyl)-cyclopenta[b]pyrrole-3aR-carboxylic acid ethyl ester Aa by means of NMR spectrum. This result implied that the asymmetric carbon-carbon bond forming reaction occurred preferentially at the ${\beta}-face$ of Ba.

• Analytical Science and Technology
• /
• v.27 no.6
• /
• pp.321-332
• /
• 2014

The accumulation levels of hexabromocyclododecanes (HBCDs) were measured in samples of muscle tissue from crucian carp (Carassius auratus) and also in samples of associated sediments. Samples were collected from 15 sites along the courses of four major rivers. Widespread contamination by HBCDs in this area was identified from the results of this investigation. HBCDs were found above the detection limit from all of the sampling sites. The ${\Sigma}HBCDs$ (sum of ${\alpha}$-, ${\beta}$-, and ${\gamma}$-HBCDs) levels ranged from 1.3 to 19 ng/g (lipid wt) in the crucian carp musscle tissue samples, and from 0.17 to 30 ng/g (dry wt) in the associated sediment samples. The predominance of ${\alpha}$-diastereomer in the muscle tissue of the carp and ${\gamma}$-diastereomer in the sediments was identified, accounting for 88% and 60% of the ${\Sigma}HBCDs$, respectively. The ${\Sigma}HBCDs$ levels in the muscle tissue samples of carp collected from the upstream sections of each river were much lower than those in the samples from carp in the downstream sections. In addition, the ${\Sigma}HBCDs$ levels in carp tissue samples from an isolated site were much lower than those in carp collected from the sites along the major rivers. This suggests that HBCD contamination in the rivers is likely to be sourced from the environment adjacent to them.

• Journal of the Korean Chemical Society
• /
• v.41 no.3
• /
• pp.150-156
• /
• 1997

A precursor of bulgecinine, (4S,5R)-1-acetyl-2-formyl-5-benzyloxymethyl-4-pyrrolidinol (15) has been synthesized from diacetone-D-glucose. Barton deoxygenation, conversion to an L-sugar and displacement with $N_3^-$ at C-5, and one-pot reductive cyclization at C-2 produced (6R)-6-Ο-benzyloxymethyl-(3R)-3-methoxy-2-oxa-5-azabicyclo-[2,2,1]heptane(13), a key intermediate for bulgecinine. N-Acetylation and acid hydrolysis of 13 furnished a precursor of bulgecinine, (2S,4S,5R)-pyrrolidinol derivative 15 and its (2R,4S,5R)-diastereomer.

• Journal of the Korean Chemical Society
• /
• v.57 no.4
• /
• pp.447-454
• /
• 2013

In this research, two new complexes of N-(2-aminoethyl)-1,3-propanediamine (aepn), $[Cd(aepn)_2]I_2$ (1) and $[Cd(aepn)_2]Cl_2{\cdots}H_2O$ (2), were prepared and identified by elemental analysis, FT-IR, Raman spectroscopy and single-crystal X-ray diffraction. Geometry around the cadmium atom in two complexes by coordination of six nitrogen atoms of two aepn is distorted octahedral. If distortion in the mer-$[Cd(aepn)_2]^{2+}$ cation is disregarded, it has a $C_2$ axis and $C_2$ symmetry. The cyclic voltammetry experiments were carried out to study the complexation process. Two structural surveys on coordination modes and complexes of aepn are presented. A study was carried out using CSD data to estimate the averages of bond lengths for different types of the Cd-N bonds. It was found that the intermolecular $N-H{\cdots}I$, $C-H{\cdots}I$ hydrogen bonds in 1 and $N-H{\cdots}Cl$, $N-H{\cdots}O$, $C-H{\cdots}O$, $O-H{\cdots}Cl$ in 2 stabilized the crystal networks.

• Korean Journal of Pharmacognosy
• /
• v.51 no.4
• /
• pp.297-301
• /
• 2020

Silymarin (SM) and silybin diastereomers (SD) in milk thistle (Silybum marianum) were determined using high-performance liquid chromatography and quantified using a reverse-phase column in a gradient elution system. UV detection was performed at 288 nm. The content of SM and SD in milk thistle was 3.236 and 0.553 mg/g DW, respectively. Determining the presence and quantifying the content of SM and SD in milk thistle are vital for the pharmaceutical industry to identify optimal sources for developing health supplements or therapeutics.