• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.2890-2896
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• 2012

A simple regioselective synthesis of cinnoline derivatives was achieved by a one-pot three component synthetic methodology. New substituted 7,8-dihydrocinnolin-5(6H)-ones are prepared via one-pot three component reaction of arylglyoxals with 1,3-cyclohexanedione and dimedone in the presence of hydrazine hydrate in moderate to good yields.

• 대한화학회지
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• 제26권2호
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• pp.107-113
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• 1982

티안트렌양이온 자유라디칼의 아세토니트릴 용액에 의해 티오크잔틴이 산화되어 생성된 티오크잔틸이움 이온에 디메돈을 넣어주면 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthylium 과염소산염(2)이 생성되나 순서를 바꾸어 넣어주면 초기에 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthene (1)이 생성되며 이것은 계속 반응하여 2를 만든다. 화합물 2는 물이 섞인 아세톤에서 쉽게 탈 수소화되어 9-(4,4-dimethylcyclohexane-2,6-dionylidene)thioxanthene (3)이 된다. 그러나 물이 섞인 아세토니트릴용액중에서 관찰된 219, 289, 348 nm의 isobestic point는 3이 2와 평형상태로 존재함을 말한다. 3의 380nm 근처에 있는 흡수띠의 위치와 강도는 용매에 따라 변하는데 이것은 용매-용질 사이의 상호작용으로 설명한다.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.1989-1995
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• 2009

Efficient one-pot synthesis of arylmethylene bis(3-hydroxy-2-cyclohexene-1-ones) and xanthenediones by EDDA and In($OTf)_3$-catalyzed reactions was developed starting from dimedone and aryl aldehydes. The key strategies of these reactions involve domino Knoevenagel/Michael reaction or Koevenagel/Michael/Cyclodehydration reactions. The scope and limitation of the two catalysts under various reaction conditions were investigated and described.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2243-2248
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• 2011

Carbon-based solid acid catalyst was found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst for the multicomponent reaction of dimedone, aromatic aldehydes, and a nitrogen source (ammonium acetate or aromatic amines) under solvent-free conditions, giving rise to 1,8-dioxodecahydroacridines in high yields. The present methodology offers several advantages, such as a simple procedure with an easy work-up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents.

• 대한화학회지
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• 제57권4호
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• pp.472-475
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• 2013

An efficient and environmentally benign protocol for the three-component synthesis of triazoloindazoles and indazolophthalazines via condensation of dimedone, aldehydes and urazole or phthalhydrazide catalyzed by $ZrOCl_2.8H_2O$ as an inexpensive and eco-friendly catalyst with high catalytic activity under solvent-free conditions is reported. This protocol provides a new and improved method for obtaining triazoloindazoles and indazolophthalazines in terms of good yields, simple experimental procedure and short reaction time.

• 대한화학회지
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• 제55권6호
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• pp.936-939
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• 2011

Thiamine hydrochloride (VB1) has been used as an acid catalyst in organic synthesis. One pot three component Biginelli condensation of dimedone, urea/thiourea and substituted aromatic aldehydes catalyzed by 10 mol % of thiamine hydrochloride (VB1) in solvent free condition under microwave irradiation in good to excellent yields has been investigated. Utilization of microwave irradiation, simple reaction conditions, short reaction time, ease of product isolation, and purification makes this manipulation very interesting from an economic and environmental perspective.

• Bulletin of the Korean Chemical Society
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• 제30권11호
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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.

• Archives of Pharmacal Research
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• 제11권2호
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• pp.114-121
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• 1988

To gain insight into possible cellular protective mechanisms against the insult of formaldehyde, we have investigated this molecule's reactivity with both naturally occurring thiol compounds including glutathione and L-ascorbic acid. By UV measurements, for maldehyde was found to rapidly react with glutathione forming an S-hydroxymethyl covalent adduct. The adduct which was confirmed by NMR is transiently stable. Formaldehydissimilar to its reaction with dimedone. The reaction of formaldehyde with glutathione was reduced by 40% in the presence of an excess amount of L-ascorbic acid, due to the trapping of formaldehyde by L-ascorbic acid. The data suggest that L-ascorbic acid may have a possible in vivo role in the metabolism of formaldehyde, thereby protecting cellular glutathione from possible depletion.

• Bulletin of the Korean Chemical Society
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• 제24권8호
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• pp.1141-1149
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• 2003

The structures and gas-phase ionization energies (ΔG°) of Meldrum's acid (I) and related cyclic (II-VI) and acyclic compounds (VII-IX) are investigated theoretically at the MP2/6-31+$G^*$, B3LYP/6-31+$G^*$, B3LYP/6- 311+$G^{**}$, B3LYP/6-311++G(3df,2p) and G3(+)(MP2) levels. Conformations of three neutral cyclic series vary gradually from boat (Meldrum's acid, I), to twisted chair (II) and to chair (III) as the methylene group is substituted for the ether oxygen successively. The preferred boat form of I can be ascribed to the two strong $n_O$ → σ* c-c antiperiplanar vicinal charge transfer interactions and electrostatic attraction between negatively charged C¹ and positively charged C⁴at the opposite end of the boat. All the deprotonated anionic forms have half-chair forms due to the two strong $n_C$ → π* c=0 vicinal charge transfer interactions. The dipole-dipole interaction theory cannot account for the higher acidity of Meldrum's acid (I) than dimedone (III). The origin of the anomalously high acidity of I is the strong increase in the vicinal charge transfer ($n_C$ → π* c=0) and 1,4-attrative electrostatic interactions (C¹↔C⁴) in the ionization (I → $I^-$ + $H^+$). In the acyclic series (VII-IX) the positively charged end atom, C⁴, is absent and the attractive electrostatic stabilization (C¹↔C⁴) is missing in the anionic form so that the acidities are much less than the corresponding cyclic series.