• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2990-2994
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• 2014

The studies on design and synthesis of new monocyclic ${\beta}$-lactam esters 4(R/S)-(1'-methoxycarbonylpropyl- 2'(R/S)-thio)-3(R)-phenylacetamidoazetidin-2-one (3a) and 4(R/S)-(1'-methoxycarbonyl-2'-methylpropyl-2'- thio)-3(R)-phenylacetamidoazetidin-2-one (3b) were described. Compounds 3a and 3b were specifically designed to retain all penicillin substructures except the bicyclic system, which would be conceived by cleaving the C(3)-N(4) bond of penicillin G. Compounds 3a and 3b are of particular interest in the context of the structural elucidation of monocyclic ${\beta}$-lactams originated from penicillin. Key intermediates, ${\beta}$-mercapto esters 6a and 6b, were synthesized from conjugate acids 4a and 4b using three-step synthetic sequences, respectively, and 4(S)-acetoxy-3(S)-phenylacetamidoazetidin-2-one (7) was obtained from the degradation of penicillin G. Reactions of 6a and 6b with 7, thus obtained, provided the target compounds 3a and 3b, respectively.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.484-488
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• 2006

The solid-phase synthesis of new series of 1,6,8-trisubstituted tetrahydro-2H-pyrazino[1,2-a]pyrimidine-4,7-diones as bicyclic $\beta$-turn mimetics is described. Their NF-kB inhibition activities were tested and the effect of substituents on bicyclic ring was investigated. Among the prepared compounds, the fluorobenzyl and methoxybenzyl group substituted compounds 26 and 27 at C-1 and C-8 position showed more inhibitory activities than the others. Tested at a concentration of 10 uM, these two compounds showed a 60% inhibition against the target NF kB 549.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.499-504
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• 2011

In this paper, we suggest a method for discretized frequency modulations of ultrasonic signals. A continuous sweep of frequency modulation signals can be modelled with fine levels of discretization. If the ultrasound signals are modulated with monotonically decreasing frequencies, then the cross-correlation between an emitted signal and received signal can be used to identify the distance of multiple target objects. For the discretized frequency synthesis, CF ultrasounds with different frequencies are serially ordered. The auto-correlation test with the signal shows effective results for distance estimation. The discretized frequency syntheses have better distance resolution than CF ultrasound signals and the resolution depends on the number of the combined ultrasound frequencies.

• Journal of the Korean Chemical Society
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• v.60 no.4
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• pp.257-260
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• 2016

A new perfluorobutyl substituted cyclic type disodium alkanesulfonate is designed, synthesized and characterized as alternative substance to perfluorooctane sulfonic acid (PFOS, 1), a well-known surfactant. Cylic type sulfonate was accomplished from commercially available 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol in four steps. Bio-degradable perfluorobutyl moiety was introduced from fluorous diol, which is symmetrically substituted amphiphile via installation of an intermediate trifluoromethanesulfonyl ester and easily manipulated by double displacement of triflate using potassium malonate and further reduction followed by nucleophilic ring opening are key reactions to get target disodium alkanesulfonate. The efficiency and simplicity in the synthesis of this material offer a new strategy to design PFOS alternatives.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2626-2630
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• 2009

2'($\beta$)-Hydroxymethylated adenosine is a potent and selective inhibitor of hepatitis C virus (HCV) replication. It targets the RNA-dependent RNA polymerase of HCV, NS5B. Synthesis and antiviral evaluation of carbocyclic versions are described. The cyclopentene intermediate ($9\beta$) was successfully synthesized through sequential Johnson-Claisen orthoester rearrangement and ring-closing metathesis (RCM). Coupling of bases via a Pd(0) catalyst, selective dihydroxylation, and desilylation yielded the target nucleoside analogues. The compounds 17 and 18 were assayed for their ability to inhibit HCV RNA replication in a subgenomic replicon Huh7 cell line and showed moderate antiviral activity with toxicity up to 20.0 and 24.7 ${\mu}g/mL$, respectively.

• Archives of Pharmacal Research
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• v.28 no.7
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• pp.745-749
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• 2005

A simple synthetic route for the synthesis of novel methyl branched cyclopropyl phosphonic acid nucleosides is described. The characteristic cyclopropyl moiety 8 was constructed by employing Simmons-Smith reaction as a key step. The condensation of mesylate 11 with natural nucleosidic bases (A,C,T,U) under standard nucleophilic substitution conditions ($K_2CO_3$, 18-Crown-6, DMF) and after subsequent hydrolysis resulted in the formation of target nucleosides, 16, 17, 18, and 19. In addition, the antiviral evaluations of the synthesized nucleotides against various viruses were also performed.

• YAKHAK HOEJI
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• v.51 no.2
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• pp.103-107
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• 2007

In these study novel 1,4-disubstituted carbocyclic nucleoside analogues were synthesized as potential antiviral agents. The coupling reaction of the alcohol 8${\alpha}$ with natural bases using Mitsunobu reaction afforded the target nucleosides 13, 14. The synthesized compounds were evaluated for their antiviral activity against various viruses such as HIV-1, HSV-1, HSV-2 and HCMV. Cytosine derivative 13 exhibited moderate antiviral activity against HIV-1 (EC$_{50}$=16.4 ${\mu}$M).

• Molecules and Cells
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• v.41 no.8
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• pp.705-716
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• 2018

The endoplasmic reticulum (ER) is a critical organelle for protein synthesis, folding and modification, and lipid synthesis and calcium storage. Dysregulation of ER functions leads to the accumulation of misfolded- or unfolded-protein in the ER lumen, and this triggers the unfolded protein response (UPR), which restores ER homeostasis. The UPR is characterized by three distinct downstream signaling pathways that promote cell survival or apoptosis depending on the stressor, the intensity and duration of ER stress, and the cell type. Mammalian cells express the UPR transducers IRE1, PERK, and ATF6, which control transcriptional and translational responses to ER stress. Direct links between ER stress and immune responses are also evident, but the mechanisms by which UPR signaling cascades are coordinated with immunity remain unclear. This review discusses recent investigations of the roles of ER stress in immune responses that lead to differentiation, maturation, and cytokine expression in immune cells. Further understanding of how ER stress contributes to the pathogenesis of immune disorders will facilitate the development of novel therapies that target UPR pathways.

• Journal of the Korean Applied Science and Technology
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• v.25 no.2
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• pp.240-251
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• 2008

The central role of tyrosine phosphorylation in cell proliferative signaling mechanisms provides another target for chemotherapy. The aim of this research is to develop new quinazoline derivatives that possess the inhibitory activity for depidermal growth factor receptor (EGFR) tyrosine kinase (TK) as protein kinase inhibitors. In this work, a series of new 4-anilino-6-guanidino-7-methoxyquinazoline derivatives (12a-l) were synthesized by the introduction of guanidine moiety at C-6 of quinazoline nucleus and evaluated for their EGFR TK inhibitory activities.

• Bulletin of the Korean Chemical Society
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• v.4 no.2
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• pp.61-63
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• 1983

A new practical method is described for the synthesis of (Z)-7-eicosen-11-one (1) and (Z)-7-nonadecen-11-one (2), the active principles of the sex pheromone of the peach fruit moth. Lithium anion of 1-octyne (from acetylene and 1-bromohexane) was alkylated with 3-bromo-1-propanol tetrahydropyranyl ether and deprotected to afford 4-undecyn-1-ol, which was oxidized with pyridinium chlorochromate to 4-undecyn-1-al. 4-Undecyn-1-al was treated with 1-nonylmagnesiumbromide or 1-octylmagnesiumbromide to yield 7-eicosyn-11-ol and 7-nonadecyn-11-ol. Jones oxidation, followed by Lindlar catalytic hydrogenation afforded the target compounds. Biological activity of the synthetic pheromones as attractants for males of the peach fruit moth was tested in the field using polyethylene capsules as containers. For each vial containing about 3.0 mg of the synthetic pheromone, the number of trapped moths were counted.