• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3963-3966
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• 2011

A series of pyranopyrazoles, was efficiently synthesized via one-pot, four component reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes and malononitrile in the presence of catalytic amount silicotungstic acid under solvent free condition. NOE experiments confirmed that the product exist exclusively in the 2H form. The present protocol offers the advantages of clean reaction, short reaction time, high yield, easy purification and economic availability of the catalyst.

• Journal of the Korean Chemical Society
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• v.58 no.5
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• pp.445-449
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• 2014

A convenient and efficient method has been developed for the one-pot synthesis of dihydropyrimidinones (DHPMs) compounds. Dihydropyrimidinone derivatives were synthesized in good yields using ethyl acetoacetate, aldehyde (aromatic and aliphatic) and urea or thiourea in the presence of ZnO nanoparticles as a catalyst in $H_2O$ as solvent at $80^{\circ}C$. This green chemistry procedure applied to the Biginelli reaction using ZnO nanoparticles as catalyst and illustrated as a rapid preparation of DHPMs in water as solvent. The products were identified by physical data (mp) by comparison with those reported in the literatures.

• Journal of the Korean Applied Science and Technology
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• v.6 no.2
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• pp.21-28
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• 1989

1-naphthol-2-sulfonic acid and 1-naphthol-4-sulfonic acid were synthesized under the dissolution of 1-naphthol in 2-nitrotoluene with stirring 98.08-90％ sulfuric acid at $5-95^{\circ}C$ for 1-5 hours. As the reaction temperatures and the reaction time were raised, the yield of 2-sulfonate was decreased, while that of 4-sulfonate was increased. But we could not observe the tendency to the various reaction concentrations of sulfuric acids. The mixtures of two isomeric 1-naphtholulfonic acids in excess concentrated sulfuric acids was quantitatively determinded by using multicomponent spectrophotomeric analysis method on the basis of the ultraviolet absorption peak of the sulfonic acids. The standard deviation in this method was ${\pm}\;2.6$, and the above method seem to be rapid and accurate.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.39-42
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• 2012

The use of Smiles rearrangement in Ugi-type couplings with tropolone allows very straightforward multicomponent formation of 2-(N,N-dialkylamino)-2,4,6-cycloheptatrien-1-one derivatives. The Ugi four-component reaction of isocyanides with tropolone (2-hydroxy-2,4,6-cycloheptatrien-1-one), primary amines and aldehydes proceeds smoothly and cleanly under mild conditions to afford 2-(N,N-dialkylamino)-2,4,6-cycloheptatrien-1-one derivatives in fairly good yields.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4127-4130
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• 2012

We report a fast, efficient, and facile route for the synthesis of 2,5-dihydro-5-imino-2-methylfuran-3,4-dicarboxylate derivatives from the isocyanide, dialkyl acetylenedicarboxylate and acetic anhydride under ultrasound-assisted conditions. Utilization of easy reaction conditions, very high to excellent yields, and short reaction times makes this manipulation potentially very useful.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2532-2534
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• 2009

A facile and efficient synthetic route has been developed for the polyhydroquinoline via four component reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in the presence of catalytic amount of scolecite in ethanol at 70 ${^{\circ}C}$ through Hantzsch reaction. This method gives remarkable advantages such as simple work-up procedure, environmentally friendly, inexpensive, non-toxic and recyclable catalyst, shorter reaction time along with excellent yields.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.119-121
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• 2004

A new and efficient synthesis of the novel bioactive bis(benzopyrano) fused dihydropyridines is described. The conventionally developed route is a two step multicomponent condensation reaction. This is latter modified by a one pot microwave (MW) assisted reaction using inorganic solid support via the arylidene derivative intermediate. With this environmentally benign approach, the reaction time is brought down from hours to minutes along with a yield enhancement. Furthermore, the role of different solid supports is studied and it is concluded that the acidic alumina is the best solid support for the present investigation.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2825-2828
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• 2013

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.169-171
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• 2013

• Journal of the Korean Chemical Society
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• v.59 no.4
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• pp.284-288
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• 2015

Three-component one-pot synthesis of 2-amino-3-cyano-7-hydroxy-4H-chromenes, which have been reported from condensation of malononitrile, aryl aldehydes and resorcinol in the presence of L-proline under reflux conditions in ethanol.