• Bulletin of the Korean Chemical Society
• /
• v.29 no.3
• /
• pp.604-608
• /
• 2008

A series of N-alkenyl pyrrolidine-2-thiones were synthesized by the reaction between pyrrolidine-2-thione and various aldehydes such as n-propanal, isopropanal, n-butanal, n-hexanal, n-octanal and phenylacetaldehyde in 32-86% yields using microwave irradiation technique. Only one structural E isomers were predominantly formed within 15 minutes in chlorobenezene?/p-toluenesulfonic acid monohydrate.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.241.2-241.2
• /
• 2003

We report the synthesis of key intermediates for the development novel flavonoid derivatives with potential antiinflammatory activity and propose a mechanism of the one-pot reaction. The various amines (1) for this work were commercially available. Secondary amines (2) were formed by nucleophilic attraction using ethyl benzoylacetate. The C-N bond formation proceeded at refluxing in toluene with catalytic amount of p-toluenesulfonic acid and a removal of water was important in this reaction. (omitted)

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.183.2-183.2
• /
• 2003

We report the synthesis of 3,4-dihydro-2-oxo-4-quinolines 5a-e for the development novel flavonoid derivatives with potential antiinflammatory activity and propose a mechanism of the one-pot reaction. The various amines (la-e) for this work were commercially available. We isolated that ester (2a-e) were formed by nucleophilic attraction using ethyl benzoylacetate. The C-N bond formation proceeded at refluxing in toluene with catalytic amount of p-toluenesulfonic acid and a removal of water and ethanol was important in this reaction. (omitted)

• Membrane Journal
• /
• v.23 no.1
• /
• pp.80-91
• /
• 2013

Metal-templated condensation of cyclohexanedione dioxime and phenylboronic acid in the presence of Fe(II) sulfate heptahydrate proceeds cleanly in methanol to furnish the Fe(II) clathrochelate. An organic/inorganic hybrid membranes composed of Fe(II) clathrochelate and polyethersulfone was prepared by using phase inversion method. For membrane preparation, the Fe(II) clathrochelate was highly soluble (3~5 g/L) in DMF, NMP, and DMAc, which meets the requirements for the solubility of metal complexes in polar aprotic solvent used in membrane preparation. It was stable even in the presence of strong acids, such as trifluorosactic acid (pKa = 0.3). It was characterized by UV-vis spectroscopy, and their stability in solution phase studied in the presence of (i) strong acids or (ii) competing chelates. Organic/inorganic hybrid membranes were prepared with polyethersulfone, polyvinylpyrrolidone, p-toluenesulfonic acid, Fe(II) clathrochelate and DMF by using nonsolvent induced phase inversion method. The addition of Fe(II) clathrochelate leads increase of surface pore density, mean pore size and flux. We can obtain highly asymmetric membranes by addition of Fe(II) clathrochelate.

• Journal of the Korean Chemical Society
• /
• v.56 no.3
• /
• pp.348-356
• /
• 2012

In an attempt to find a new class of bisazo disperse dyes with better dyeing properties, a series of novel bisazo dyestuffs based on 4-arylhydrazono-3-(2'-hydroxyphenyl)-1-phenyl-2-pyrazolin-5-ones $\mathbf{3a-f}$ were prepared by diazocoupling of p-nitrophenyl diazonium chloride with 4-arylhydrazono-3-(2'-hydroxyphenyl)-1-phenyl-2-pyrazolin-5-ones $\mathbf{2a-f}$. Compounds $\mathbf{3a-f}$ were subsequently reacted with acetic anhydride in the presence of p-toluenesulfonic acid afford the corresponding O-acetyl derivatives $\mathbf{4a-f}$. The latter products as well as spectral data indicated that compounds $\mathbf{3a-f}$ exist predominantly in the azo-hydrazone tautomeric form (H) as the ZE-configuration. Additionally, two series of the synthesized dyes $\mathbf{3a-f}$ and $\mathbf{4a-f}$ were applied as disperse dyes for dyeing polyester fabrics and their fastness properties were evaluated. Also the position of color in CIELAB coordinates ($L^*$, $a^*$, $b^*$, $H^*$, $C^*$*) was assessed.

• Applied Chemistry for Engineering
• /
• v.27 no.5
• /
• pp.490-494
• /
• 2016

This paper describes the very efficient and highly enantioselective ring opening of terminal epoxides with alkyl and arene sulfonic acid. The dinuclear chiral (salen) Co complexes bearing Lewis acids of Al, Ga and In catalyze the reaction enantioselectively in the presence of tetrabutylammonium chloride using tert-butyl methyl ether as a solvent. The variation of the anion of the tetra butyl ammonium salt has significant impact on the reactivity and selectivity of the asymmetric ring opening of phenyl glycidyl ether with p-toluenesulfonic acid. The order of reactivity and selectivity was found to be $Cl^-$ > $l^-$ > $Br^-$ > $OH^-$. Strong synergistic effects of the different Lewis acid centers of Co-Al, Co-Ga and Co-In complexes were observed in the catalytic process. The dinuclear chiral salen catalyst containing $AlCl_3$ was found to be most active and highly enantioselective (91% ee).

• Archives of Pharmacal Research
• /
• v.11 no.1
• /
• pp.33-40
• /
• 1988

Two new nitro analogs of tranylcypromine, (E)-2-(p-nitrophenyl)cyclopropylamine ((E)-p-NTCP) and (E)-2-(m-nitrophenyl)cyclopropylamine ((E)-m-NTCP) were synthesized in order to examine the effect of aromatic nitro substitution on the MAO-inhibitory activity of 2-phenylcyclopropylamines. The compounds were obtained by treating t-butyl (E)-2-(p-nitrophenyl) cyclopropanecarbamate and t-butyl (E)-2-(m-nitrophenyl)cyclopropanecarbamate with p-toluenesulfonic acid in $CH_3$CN. Inhibitions of rat brain mitochondrial MAO-A and B by the compounds were examined using serotonin and benzylamine as the substrate at both in vitro and ex vivo levels. It was found from in vitro measurements that (E)-p-NTCP at $6.0{\times}10^{-5}M$ elicited merely 22.5% inhibition against MAO-B without any effect on MAO-A. In contrast, (E)-m-NTCP showed fair degrees of inhibitions of MAO-A and B with $IC_{50}$ values, $2.5{\times}10^{-7}M\;and\;1.4{\times}10^{-6}M$, respectively. It was also noted from (E)-m-NTCP that m-nitro substitution caused a shift of selectivity of the inhibition toward MAO-A. According to ex vivo measurements at 1.5, 3, 6, and 12 hr following the administration of a dose of 0.015 mmol/kg, i.p. to the rats, the inhibition percents of MAO-A by (E)-m-NTCP were 58.6, 63.7 63.6, and 46.6%, slightly lower than those observed by tranylcypromine. Whereas, (E)-m-NTCP at the same dose level did not show significant inhibitions against both MAO-A and MAO-B. Possible reasons for the difference in potencies between (E)-m-NTCP and (E)-p-NTCP were sought in relation to differing electron withdrawing effects of m- and p-substituents which will influence electron density of the side chain amino functions and the partitions.

• KSBB Journal
• /
• v.19 no.5
• /
• pp.385-389
• /
• 2004

In this research, the chemo-enzymatic synthesis of sorbitan methacrylate was investigated to optimize reaction conditions. Firstly, sorbitan was manufactured by sorbitol cyclic reaction in the presence of p-toluenesulfonic acid (p-TSA) as catalyst material. Secondly, sorbitan methacrylate was synthesized by immobilized lipase Novozyme 435 with acyl donors in t-butanol. As a result of enzymatic synthesis of sorbitan methacrylate, the conversion yield reached about $65\%$ in the condition of initial sorbitan conc. 50 g/L, enzyme content $3\%$ (w/v) , molar ratio 1:3, reaction temperature 50^{circ}C and reaction time 42 hrs using methyl methacrylate as acyl donor. Comparing with acyl donors and reaction temperature, the conversion yield reached about 18, 65 and $80\%$ with methacrylic acid, methyl methacrylate and vinyl methacrylate as acyl donor, respectively. And optimum reaction temperature was 60, 50, and 50^{circ}C, respectively

• KSBB Journal
• /
• v.5 no.1
• /
• pp.81-85
• /
• 1990

Lignin was extracted from the rice straw by using the solvent mixture of buthyl alcohol and distilled water. And the experiment of vanillin production from extracted lignin was performed with the oxidation catalysts; CuO, Cu(OH)2 and CuSO4.5H2O. The optimum conditions of lignin extraction are the reaction temperature 12$0^{\circ}C$ and the mixture of 250mL buthyloloohol, 250mL, distilled water and 25g rice straw in the presence of 2.5g p-toluenesulfonic acid. The yield of vanillin from extracted lignin increased linearly with the increase of reaction temperature. And it increased with the order of Cu(OH)<$_2$ CuO$_4\cdot \;5H_2$Oas oxidation catalysts. The maximum yield of vanillin was 9% in the presence of 2.5%(w/v) CuSO$_4\cdot \;5H_2$O under the following conditions: temperature, 18$0^{\circ}C$; pressure, 13atm; pH 4.0 and reaction time, two hours.

• Journal of the Korean Applied Science and Technology
• /
• v.18 no.2
• /
• pp.153-159
• /
• 2001

Due to its low density, good mechanical properties and chemical inertness, glassy carbon(GC) has been studied for appications in several fields. A raw thermosetting resin of furanic resin was polymerized with a curing agent of p-toluenesulfonic acid monohydrate. The maximum yield of GC was obtained at the curing agent content of 1.0 wt% in furanic resin. In order to make thick GC, the affect of graphite filler addition to the furanic resin was investigated. The density and electrical resitivity of GC after graphitization were 1.45 $g/cm^{3}$ and 47 ${\times}10^{-4}$ ${\Omega}$ ${\cdot}$ cm respectively and the amorphous structure of GC was confirmed by XRD profiles with very broad peaks comparable to those of graphite at $206^{\circ}$ and $45^{\circ}$.