• Journal of the Korean Chemical Society
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• v.68 no.3
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• pp.131-134
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• 2024

A simple strategy for the formal synthesis of the sex pheromone of gypsy moth (+)-disparlure from L-(+)-tartaric acid is described herein. The key steps include the mono-esterification and regioselective ring-opening of an epoxide using a Grignard reagent. The strategy of conferring asymmetry using 2-butanone enables mono-esterification in high yield and reduces the number of steps. Subsequently, (+)-disparlure is synthesized via the regioselective ring opening of the epoxide.

• Journal of the Korean Graphic Arts Communication Society
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• v.16 no.3
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• pp.1-13
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• 1998

Some photopolymer, poly(vinyl cinnamoyl acetate)(PVCiA) was synthesized by esterification of polymer(vinyl alcohol(PVA) with monochloroacetic acid, followed by reaction poly(vinyl monochloroacetate)(PVChA) and potassium cinnamate. When esterification of PVA with monochloroacetic acid was reacted in the dimethyl sulfoxide(DMSO), in the synthesis of PVChA, it is very good yield and the successive cinnamoyl acetoxyl esterification of PVCiA can be successfully synthesized. But PVCiA is low photosensitive polymer if not added photosensitizing dyes. Here, we synthesized photosensitizing dyes. trifluoromethylindol squarylium dye derivatives(TFSQ). Indolization of 3-trifluoromethylphenyl-hydrazine formed 4- and 6-substituted indoles, the rate of 4- and 6-substituted indoles is close to unity. Absorption's coefficient of 1,3-bis(4-trifluoromethyl-1,3,3-trimethylindol) squarylium dye(TFSQ) is 7.57$\times$10\ulcorner, PVCiA added with TFSQ(3%) was highly sensitized six times than not added.

• Bulletin of the Korean Chemical Society
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• v.3 no.2
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• pp.70-76
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• 1982

Synthetic utility of 1-fluoro-2,4,6-trinitrobenzene (FTNB) as a condensing agent was investigated. The use of FTNB and DMAP was found to be very effective for direct esterification of carboxylic acids with alcohols or thiols. However, this system was not very effective for macrolactonization. Reaction of 2,4,6-trinitrophenyl esters with several nucleophiles was investigated briefly. Plausible reaction mechanisms of esterification are presented. It seems that the reaction proceeds via the intermediacy of 2,4,6-trinitrophenyl esters by initial formation of 2',4',6'-trinitrophenyl-4-dimethylaminopyridinium salt from which the trinitrophenyl group is transferred to the carboxylic acid.

• Elastomers and Composites
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• v.49 no.2
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• pp.110-116
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• 2014

We investigated the effect of the concentration of stannous 2-ethylhexanoate catalyst on the esterification rate between adipic acid (AA) and each of two PEG oligomers, diethylene glycol (DEG) and polyethylene glycol (PEG600). The concentration of the catalyst was varied from 0.15 to 2.0 wt.%. To attach hydroxy group to each end of the poly(oxyethylene-co-adipate) synthesized from AA and the PEGs, the esterification was performed with excessive PEG oligomers ([PEG]/[AA]=2) at $170^{\circ}C$. The degree of polymerization of the poly(oxyethylene-co-adipate)diol products were three. The apparent rate constant ($k_{app}$) of the esterification between AA and DEG shows the first order dependency on the catalyst concentration ($k_{app}=0.88[C_{cat}]$), whereas the $k_{app}$ of the esterification between AA and PEG600 has a relation of $k_{app}=0.123[C_{cat}]^{0.55}$ with the catalyst concentration. It is expected that the rate of esterification between AA and DEG has a non-linear dependency on the catalyst concentration as the catalyst concentration approaches to 0.22M.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3486-3488
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• 2011

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.448-452
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• 1994

2-Hydroxymethyl-2,5-dihydrothiophene 1,1-dioxide (1) was prepared from thiophene-2-carboxylic acid by consecutive reactions involving the Birch reduction, esterification, reduction with lithium aluminum hydride, and oxidation with Oxone$^{\circledR}$. The esterification of alcohol 1 with various unsaturated carboxylic acids provided the precursors 8 for the intramolecular Diels-Alder reaction. The cheletropic expulsion of sulfur dioxide from the esters 8 followed by intramolecular Diels-Alder reaction furnished bicyclic ${\gamma}$-and ${\delta}$-lactones.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.399-404
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• 2003

Aliphatic polyester, especially poly(butylene adipate)(PBA), is quite biodegradable and one of the most promising polymer materials to be commercialized. Bis(4-hydroxybutyl) adipate (BHBA) formation stage is the first principal process in the production of PBA from adipic acid (AA) and 1,4-butane diol (BD). In this study, we investigated for the effective production of Bis(4-hydroxybutyl) adipate (BHBA), effects of molar ratio of adipic acid (AA) to 1,4-butane diol (BD), catalyst (tetrabutyl titanate, TBT) concentration, and temperature on the reaction rate of esterification between AA and BD were investigated. Initial reaction rate of the esterification decreased with increasing molar ratio of AA to BD and reaction temperature, whereas reaction constant increased with increase in catalyst-concentration. Activation energy values for catalyzed and uncatalyzed esterifications were 198.5 and 94.8 kJ/mol, respectively.

• Proceedings of the Ginseng society Conference
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• 2002.10a
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• pp.317-334
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• 2002

Ginsenosides are metabolized (deglycosylated) by intestinal bacteria to active forms after oral administration. 20(S)-Protopanaxadiol $20-O-{\beta}-D-glucopyranoside$ (M1) and 20(S)-protopanaxatriol (M4) are the main intestinal bacterial metabolites (IBMs) of protopanaxadiol- and protopanaxatriol-type glycosides. M1 was selectively accumulated into the liver soon after its intravenous (i.v.) administration to mice, and mostly excreted as bile; however, some M1 was transformed to fatty acid ester (EMl) in the liver. EM1 was isolated from rats in a recovery dose of approximately $24mol\%.$ Structural analysis indicated that EM1 comprised a family of fatty acid mono-esters of M1. Because EM1 was not excreted as bile as Ml was, it was accumulated in the liver longer than M1. The in vitro cytotoxicity of M1 was attenuated by fatty acid esterification, implying that esterification is a detoxification reaction. However, esterified M1 (EM1) inhibited the growth of B16 melanoma more than Ml in vivo. The in vivo antitumor activity paralleled with the pharmacokinetic behavior. In the case of M4, orally administered M4 was absorbed from the small intestine into the mesenteric lymphatics followed by the rapid esterification of M4 with fatty acids and its spreading to other organs in the body and excretion as bile. The administration of M4 prior to tumor injection abrogated the enhanced lung metastasis in the mice pretreated with 2-chloroadenosine more effectively than in those pretreated with anti-asialo GMl. Both EM1 and EM4 did not directly affect tumor growth in vitro, whereas EM1 promoted tumor cell lysis by lymphocytes, particularly non-adherent splenocytes, and EM4 stimulated splenic NK cells to become cytotoxic to tumor cells. Thus, the esterification of IBM with fatty acids potentiated the antitumor activity of parental IBM through delay of the clearance and through immunostimulation. These results suggest that the fatty acid conjugates of IBMs may be the real active principles of ginsenosides in the body.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.732-738
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• 2018

Novel carbon-based solid acid catalysts were synthesized through a sustainable route from lipid-extracted microalgal residue of Dunaliella tertiolecta, for biodiesel production. Two carbon-based solid acid catalysts were prepared by surface modification of bio-char with sulfuric acid ($H_2SO_4$) and sulfuryl chloride ($SO_2Cl_2$), respectively. The treated catalysts were characterized and their catalytic activities were evaluated by esterification of oleic acid. The esterification catalytic activity of the $SO_2Cl_2$-treated bio-char was higher ($11.5mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.\;^{-1}$) than that of commercial catalyst silica-supported Nafion SAC-13 ($2.3mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.^{-1}$) and $H_2SO_4$-treated bio-char ($5.7mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.^{-1}$). Reusability of the catalysts was examined. The catalytic activity of the $SO_2Cl_2$-modified catalyst was sustained from the second run after the initial activity dropped after the first run and kept the same activity until the fifth run. It was higher than that of first-used Nafion. These experimental results demonstrate that catalysts from lipid-extracted algae have great potential for the economic and environment-friendly production of biodiesel.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.375-380
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• 2006

In the paper, lipophilic derivatives of $\beta$-sitosterol, which are known to have a potential to reduce blood cholesterol level, were synthesized by the esterification of $\beta$-sitosterol and fatty acids. When the esterification reactions using stearic acid, oleic acid or linoleic acid as fatty acids were carried out in the presence of an acidic catalyst, the reaction for unsaturated fatty acids such as oleic acid and linoleic acid afforded a significant amount of side products which may be produced by oxidation of unsaturated groups. On the other hand, esterification reactions in the presence of dehydrating agents and a basic catalyst gave pure products regardless of the nature of fatty acids. The solubilities of lipophilic derivatives of $\beta$-sitostero to organic solvents and edible oil were observed to increase as the degree of unsaturation of fatty acids increases.