• Bulletin of the Korean Chemical Society
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• v.12 no.1
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• pp.26-31
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• 1991

Facile and efficient syntheses of terpenic perfumeries cis-jasmone, dihydrojasmone, and tetrahydrojasmone have been investigated. Cis-jasmone was synthesized by successive metallation followed by alkylation of acetone N,N-dimethylhydrazone with (Z)-2-penten-1-yl tosylate (or 2-pentyn-1-yl tosylate) and propylene oxide in one flask to give a ketonic alcohol, which was oxidized to the corresponding diketone, followed by base-catalyzed intramolecular aldol condensation to give a regioselective cyclization product. Dihydrojasmone and tetrahydrojasmone could be conveniently obtained from 2-octanone. The dimethylhydrazone of the ketone was lithiated with butyllithium and reacted with propylene oxide to give a ketonic alcohol, which was oxidized to a diketone, followed by base-catalyzed intramolecular cyclization to afford dihydrojasmone. Tetrahydrojasmone was prepared by converting the ketonic alcohol into corresponding iodoketone, followed by base-catalyzed intramolecular cycloalkylation to furnish an odoriferous product.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.491-500
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• 2004

The Lewis acid-catalyzed reactions of anthrone with a variety of ethylenic substrates under various conditions have been studied. It has been observed that depending on kinds of ethylenic substrates and catalysts, products were varied. In particular, the $ZnCl_2$-catalyzed reaction of anthrone with ${\alpha},{\beta}$ -unsaturated ester gave bridged compounds 3 (Diels-Alder adduct type) and mono-Michael adduct 4 exclusively, while the base-catalyzed reaction gave 10,10-bis-Michael adduct as a major product independent of the amount of ethylenic substrate and base. Bridged compounds 3 were easily converted to the corresponding mono-Michael adduct 4 by a catalytic amount of base. Further Michael reaction of mono-Michael adducts with different ethylenic substrates in the presence of a catalytic amount of alkoxide gave unsymmetrical 10,10-bis Michael adducts in good or moderate yields.

• Bulletin of the Korean Chemical Society
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• v.5 no.5
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• pp.207-208
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• 1984

The tris(hydroxymethyl)aminomethane (Tris)-catalyzed hydrolysis of p-nitrotrifluoroacetanilide was kinetically studied. On the contrary to the previously reported results (R. M. Pollack and T. C.Dumsha, J. Am. Chem. Soc., 1973, 95, 4463), the dependence of the rate on [Tris] consists of an initial curve portion and a subsequent linear increase. This indicates that erroneous conclusions were made in the reported work due to the insufficient amount of data. The initial portions of the rate[Tris] profiles are attributed to the catalyzed breakdown of the tetrahedral intermediate, and the linear portions to the general base-catalyzed water attack at the substrate.

• KSBB Journal
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• v.25 no.5
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• pp.483-489
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• 2010

Biodiesel has attracted great attention as an alternative renewable energy source for the replacement of petroleumbased diesel fuel, yet its high production cost due to expensive oil feedstock remainsas the major economical obstacle. In this study, we investigated catalysts and reaction conditions for the acid catalyzed pre-conversion of free fatty acid (FFA) to fatty acid methyl ester (FAME) in cheap low-grade oils of high acid value. The NaOH base catalyzed reaction of vegetable oil of the initial acid value of 2 mg KOH/g led to a high FAME conversion above 95.4%, but the conversion abruptly decreased at higher initial acid values. This base catalyzed reaction was practically ineffective displaying the FAME conversion below 15% even at the initial acid value of 10 mg KOH/g by the severe saponification side reaction. Among the various catalysts studied for the pre-conversion of FFA to FAME, Amberlyst-15 was the most effective in reducing the acid value, and the optimum reaction condition identified was $65^{\circ}C$ with oil to methanol ratio of 1:3 and catalyst concentration of 15% (w/w). As the results, great enhancements in the overall biodiesel conversion were achievable via a consecutive reaction of the acid catalyzed FFA pre-conversion to FAME under the optimal condition obtained with Amberlyst-15 followed by the NaOH base catalyzed reaction, far above the extent which was obtainable by the single NaOH catalyzed reaction.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.99-103
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• 2000

Acid and base catalyzed intramolecular cyclizations of N-benzoylthioureidoacetal, contain-ing four functional groups adjacent to thiourea such as benzocarbamoyl, acetal, thioure and amide, were investigated. The condensation reaction of N-benzoyl thiocarbamoylgly-cine amide in the presence of 10% aqueous NaOH provided 1-(2,2-dimethoxy)ethyl-imi- dazolidine-2-thione exclusively. In the presence of pyridine, it was transformed to 2- thiohydantoin. N-Benzoyl thiocarbamoyl glycine amide was completely transformed to an iminothiazolidine exclusively in the presence of Lewis acid such as borontrifluoride ether-ate or trimethylsilyl iodide. 1-(2,2-Dimethoxy)ethyl-imidazolidine-2-thione was transformed to imidazole[2,1-b]thiazole and pyrazino[5,1-a]imidazole in the presence of $BF_3$.$ET_2$O and formic acid, respectively.

• Bulletin of the Korean Chemical Society
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• v.17 no.7
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• pp.573-574
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• 1996

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.454-456
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• 2005

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.783-792
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• 1995

Sol-Gel derived ferroelectric PZT thin films were fabricated on ITO/Glass and Si/SiO2 substrates. In order to investigate the effect of catalysts on the densification and crystallization of PZT thin films, a nitric acid or ammonium hydroxide was added to the PZT stock solution at the state of partial hydrolysis reaction. The measured pH for a stable PZT sol was 5.2~9.3. In case of an acid-catalyzed PZT sol, a highly condensed particulate PZT sol was formed by accelerating the hydrolysis reaction. But weakly branched polymeric PZT sol was formed with a base-catalyzed condition. The difference in densification behavior was not found in the pH range of added catalyst, but the refractive index of PZT thin film was increased rapidly as the annealing temperature increased. The PZT thin film annealed at 54$0^{\circ}C$ for 10 min was fully densified and its refractive index was above 2.4. When the annealing temperature increased, the transition from the pyrochlore phase to perovskite appeared at 54$0^{\circ}C$. The base-catalyzed PZT thin film suppressed to form the pyrochlore phase and proceeded effectively to convert the perovskite phase. This was due to the formation of polymeric molecular structure by controlling the hydrolysis and condensation reaction through the additiion of the ammonium hydroxide.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.712-715
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• 2012

A simple and clean synthesis of polysubstituted 2,6-dicyanoanilines has been developed via the reaction of arylidenemalonodinitriles with 1-arylethylidenemalonodinitriles in ethanol catalyzed by KF/alumina. Use of non-hazardous solid base as a catalyst, operational simplicity and improved product yields are the key advantages of the present protocol.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2921-2927
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• 2011

This paper describes efficient synthetic approaches for isolating biologically interesting natural pyranochalcones and their unnatural derivatives from Mallotus Philippensis. The key strategies involve ethylenediamine diacetate-catalyzed benzopyran formation reactions and base-catalyzed aldol reactions.