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Search Results: 1 - 10 of 27897 matches for " Eunsook Ma "
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Synthesis of 2-(4-Methoxyphenyl)pyrrolo[2,1-d]pyrido[2,3-c]-[1,5]-thiazepin-3(2H)-one
Eunsook Ma
Molecules , 2003, DOI: 10.3390/80900678
Abstract: 2-(4-Methoxyphenyl)pyrrolo[2,1-d]pyrido[2,3-c][1,5]thiazepin-3(2H)-one, a key intermediate in the synthesis of pyrrolopyridothiazepine derivatives, was synthesized from bis(4H-pyrrolo-3-pyridyl)disulfide and α-bromo-(4-methoxyphenyl) acetic acid ethyl ester in order to develop a novel calcium channel antagonist.
Epoxidation of Diosgenin, 25(R)-1,4,6-Spirostatrien-3-one and 25(R)-4,6-Spirostadien-3β-ol
Eunsook Ma,Jongwon Kim
Molecules , 2003, DOI: 10.3390/81200886
Abstract: Upon treatment of 25(R)-spirost-5-en-3β-ol (diosgenin), 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with 30% H2O2 and 5% NaOH in methanol, diosgenin did not react, 25(R)-1,4,6-spirostatrien-3-one was converted to 25(R)-1α,2α-epoxy-4,6-spirostadien-3-one and 25(R)-4,6-spirostadien-3β-ol was oxidized to give a small amount of 25(R)-4,6-spirostadien-3-one, while most of the original starting material remained unchanged. On the other hand, reactions of diosgenin, 25(R)-1,4,6-spirostatrien-3-one and 25(R)-4,6-spirostadien-3β-ol with m-chloroperoxybenzoic acid in chloroform yielded 25(R)-5α,6α-epoxyspirostan-3β-ol, 25(R)-6α,7α-epoxy-1,4-spirostadien-3-one and 25(R)-4β,5β-epoxy-6-spirosten-3β-ol, respectively.
Epoxidation and Reduction of DHEA, 1,4,6-Androstatrien-3-one and 4,6-Androstadien-3β,17β-diol
Eunsook Ma,Eunjeong Kim
Molecules , 2005, DOI: 10.3390/10030572
Abstract: Dehydroepiandrosterone (DHEA) reacted with m-chloroperoxybenzoic acid(m-CPBA) to form 3β-hydroxy-5α,6α-epoxyandrostan-17-one (1), but it did not reactwith 30% H2O2. 1,4,6-Androstatrien-3,17-dione (2) was obtained from DHEA and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in dioxane. Compound 2 was reacted with 30%H2O2 and 5% NaOH in methanol to give 1α,2α-epoxy-4,6-androstadien-3,17-dione (3),which was stereoselectively reduced with NaBH4 to form 1α,2α-epoxy-4,6-androstadien-3β,17β-diol (7) and reacted with Li metal in absolute ethanol-tetrahydrofuran mixture togive 2-ethoxy-1,4,6-androstatrien-3,17-dione (8). Compound 2 was also epoxidized withm-CPBA in dichloromethane to afford 6α,7α-epoxy-1,4-androstadien-3,17-dione (4),which was reacted with NaBH4 to synthesize 6α,7α-epoxy-4-androsten-3β,17β-diol (9).Compound 4 was reduced with Li metal in absolute ethanol-tetrahydrofuran mixture toform 7β-ethoxy-6α-hydroxy-1,4-androstadien-3,17-dione (10). Compound 2 was reducedwith NaBH4 in absolute ethanol to form 4,6-androstadien-3β,17β-diol (5), which wasreacted with 30% H2O2 to give the original compound, but which reacted with m-CPBAto give 4β,5β-epoxy-6-androsten-3β,17β-diol (6).
Synthesis of Pregnane Derivatives, Their Cytotoxicity on LNCap and PC-3 Cells, and Screening on 5α-Reductase Inhibitory Activity
Sujeong Kim,Eunsook Ma
Molecules , 2009, DOI: 10.3390/molecules14114655
Abstract: A series of epoxy- and/or 20-oxime pregnanes were synthesized from commercially available pregnenolone. Compounds 1, 3, 7, 8 and 11-13 were evaluated for cytotoxicity activity towards LNCaP (androgen-dependent) and PC-3 (androgenindependent) prostate cancer cells. Compound 13 showed the highest activity on both LNCaP (IC50 15.17 μM) and PC-3 (IC50 11.83 μM) cell lines. Compound 11 showed weak activity on LNCaP cells (IC50 71.85 μM) and 8 showed the weak activity on PC-3 cells (IC50 68.95 μM), respectively. The 5α-reductase II (5AR2) inhibitory effects of compounds 1-3, 5 and 7-13 were investigated in a convenient screening model, in which compounds 5, 8, 11 and 12 were observed to be potential inhibitors of 5α-reductase, in particular, the 4-azasteroid 11, that also inhibited cell proliferation of androgen-dependent cells and 8, that in addition inhibited PC-3 cells more potently than LNCaP cells.
Simple and Regioselective Bromination of 5,6-Disubstituted-indan-1-ones with Br2 Under Acidic and Basic Conditions
Taeyoung Choi,Eunsook Ma
Molecules , 2007, DOI: 10.3390/12010074
Abstract: Bromination of 5,6-dimethoxyindan-1-one with Br2 in acetic acid at room temperature produced exclusively the corresponding 2,4-dibromo compound in 95% yield. Reaction of 5,6-dimethoxyindan-1-one with Br2 in the presence of KOH, K2CO3 or Cs2CO3 at ~0°C gave the monobrominated product 4-bromo-5,6-dimethoxyindan-3-one in 79%, 81% and 67% yield, respectively. 5,6-Dihydroxyindan-1-one was dibrominated on the aromatic ring affording 4,7-dibromo-5,6-dihydroxyindan-1-one both in acetic acid at room temperature and in the presence of KOH at ~0°C. 5,6-Difluoroindan-1-one and 1-indanone were α-monobrominated in acetic acid and α,α-dibrominated under KOH conditions at room temperature.
Structural Necessity of Indole C5-O-Substitution of seco-Duocarmycin Analogs for Their Cytotoxic Activity
Taeyoung Choi,Eunsook Ma
Molecules , 2010, DOI: 10.3390/molecules15117971
Abstract: A series of racemic indole C5-O-substituted seco-cyclopropylindole (seco-CI) compounds 1-5 were prepared by coupling in the presence of EDCI of 1-(tert-butyloxycarbonyl)-3-(chloromethyl)indoline (seg-A) with 5-hydroxy-, 5-O-methylsulfonyl, 5-O-aminosulfonyl, 5-O-(N,N-dimethylaminosulfonyl)- and 5-O-benzyl-1H-indole-2-carboxylic acid as seg-B. Compounds 1-5 were tested for cytotoxic activity against four human cancer cell lines (COLO 205, SK-MEL-2, A549, and JEG-3) using a MTT assay. Compounds 2 and 3 with small sized sulfonyl substituents like 5-O-methylsulfonyl and 5-O-aminosulfonyl exhibit a similar level of activity as doxorubicin against all cell lines tested.
Synthesis of 2- and 7- Substituted C19 Steroids Having a 1,4,6-Triene or 1,4-Diene Structure and Their Cytotoxic Effects on T47D and MDA-MB231 Breast Cancer Cells
Minwoo Kim,Eunsook Ma
Molecules , 2010, DOI: 10.3390/molecules15064408
Abstract: 2-Chloro-, 2-bromo- and 2-azido-1,4,6-androstatriene-3,17-diones were synthesized from 1α,2α-epoxy-4,6-androstadiene-3,17-dione (2) using HCl, HBr and NaN3, respectively. Compound 2 was also reacted with NaCN to give 2-cyano-1,4,6-androstatriene-3,17-dione (5) and 2β-cyano-1α-hydroxy-4,6-androstadiene-3,17-dione (6). 6α,7α-Epoxy-1,4-androstadiene-3,17-dione (8) was reacted with HCl, HBr and NaN3 to form the corresponding 7β-chloro-, 7β-bromo- and 7β-azido-6α-hydroxy-1,4-androstadiene-3,17-diones. The cytotoxic activity of these compounds towards T47D (estrogen-dependent) and MDA-MB231 (estrogen-independent) breast cancer cell lines was evaluated. The 6α-hydroxy-7β-substituted analogs were more active than the 2-substituted analogs on both cell lines. Compound 2 showed the highest selective activity against the T47D (IC50 7.1 μM) cell line and 5 showed good cytotoxic activity on MDA-MB231 (IC50 18.5 μM) cell line, respectively. The 6α,7α-epoxy analog 8 also showed high cytotoxic activity on both cell lines (IC50 17.3 μM on T47D and IC50 26.9 μM on MDA-MB231).
Synthesis and Screening of Aromatase Inhibitory Activity of Substituted C19 Steroidal 17-Oxime Analogs
Muna Pokhrel,Eunsook Ma
Molecules , 2011, DOI: 10.3390/molecules16129868
Abstract: The synthesis and aromatase inhibitory activity of androst-4-en-, androst-5-en-, 1β,2β-epoxy- and/or androsta-4,6-dien-, 4β,5β-epoxyandrostane-, and 4-substituted androst-4-en-17-oxime derivatives are described. Inhibition activity of synthesized compounds was assessed using aromatase enzyme and [1β-3H]androstenedione as substrate. Most of the compounds displayed similar to or more aromatase inhibitory activity than formestane (74.2%). 4-Chloro-3β-hydroxy-4-androsten-17-one oxime (14, 93.8%) showed the highest activity, while 4-azido-3β-hydroxy-4-androsten-17-one oxime (17, 32.8%) showed the lowest inhibitory activity for aromatase.
Inhibition of PCAF Histone Acetyltransferase, Cytotoxicity and Cell Permeability of 2-Acylamino-1-(3- or 4-Carboxy-phenyl)benzamides
Woong Jae Park,Eunsook Ma
Molecules , 2012, DOI: 10.3390/molecules171113116
Abstract: Small molecule HAT inhibitors are useful tools to unravel the role of histone acetyltransferases (HATs) in the cell and they also have relevance in oncology. We synthesized a series of 2-acylamino-1-(3- or 4-carboxyphenyl)benzamides 8–19 bearing C6, C8, C10, C12, C14, and C16 acyl chains at the 2-amino position of 2-aminobenzoic acid. Enzyme inhibition of these compounds was investigated using in vitro PCAF HAT assays. The inhibitory activities of compounds 8–10, 16, and 19 were similar to that of anacardic acid, and 17 was found to be more active than anacardic acid at 100 μM. Compounds 11–15 showed the low inhibitory activity on PCAF HAT. The cytotoxicity of the synthesized compounds was evaluated by SRB (sulforhodamine B) assay against seven human cancer cell lines: HT-29 (colon), HCT-116 (colon), MDA-231 (breast), A549 (lung), Hep3B (hepatoma), HeLa (cervical) and Caki (kidney) and one normal cell line (HSF). Compound 17 was more active than anacardic acid against human colon cancer (HCT 116, IC50: 29.17 μM), human lung cancer (A549, IC50: 32.09 μM) cell lines. 18 was more active than anacardic acid against human colon cancer (HT-29, IC50: 35.49 μM and HCT 116, IC50: 27.56 μM), human lung cancer (A549, IC50: 30.69 μM), and human cervical cancer (HeLa, IC50: 34.41 μM) cell lines. The apparent permeability coefficient (Papp, cm/s) values of two compounds (16 and 17) were evaluated as 68.21 and 71.48 × 10?6 cm/s by Caco-2 cell permeability assay.
Synthesis and 5α-Reductase Inhibitory Activity of C21 Steroids Having 1,4-diene or 4,6-diene 20-ones and 4-Azasteroid 20-Oximes
Sujeong Kim,Yong-ung Kim,Eunsook Ma
Molecules , 2012, DOI: 10.3390/molecules17010355
Abstract: The synthesis and evaluation of 5α-reductase inhibitory activity of some 4-azasteroid-20-ones and 20-oximes and 3β-hydroxy-, 3β-acetoxy-, or epoxy-substituted C21 steroidal 20-ones and 20-oximes having double bonds in the A and/or B ring are described. Inhibitory activity of synthesized compounds was assessed using 5α-reductase enzyme and [1,2,6,7-3H]testosterone as substrate. All synthesized compounds were less active than finasteride (IC50: 1.2 nM). Three 4-azasteroid-2-oximes (compounds 4, 6 and 8) showed good inhibitory activity (IC50: 26, 10 and 11 nM) and were more active than corresponding 4-azasteroid 20-ones (compounds 3, 5 and 7). 3β-Hydroxy-, 3β-acetoxy- and 1α,2α-, 5α,6α- or 6α,7α-epoxysteroid-20-one and -20-oxime derivatives having double bonds in the A and/or B ring showed no inhibition of 5α-reductase enzyme.
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