• Archives of Pharmacal Research
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• 제13권1호
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• pp.5-8
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• 1990

The cycloaddition of the newely synthesized 5-(2-thienyl)methylene derivatives of thiazolidinone-4-thiones, 2a-c to acrylonitrile (3a), ethylacrylate (3b), N-phenylmaleimide (6) and dimethyl fumarate (8) has been evaluated. Under thermal reaction conditions [4 +2] cycloaddition proceeds with complete site and regioselectivity to yield the cycloadduct, 4, 5, 7 and 9, respectively. The antimicrobial activities of some of the new products were tested.

• 한국응용과학기술학회지
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• 제14권3호
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• pp.39-46
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• 1997

Ultraviolet spectrophotometric investigation has been carried out on the rate constants for 1,3-dipolar cycloaddition of 4-substituted-3-phenyloxadiazole derivatives with dipolarophiles such as phenyl acetylene, propiolic acid methyl ester and dimethylacetylene dicarboxylate. From there, the rate constants for 1,3-dipolar cycloaddition were determined at 80, 100 and $120^{\circ}C$, and the reaction rates were increased with increasing temperature. From these rate constants, the values of the thermodynamic activation parameters were obtained. Some thermodynamic activation parameters such as $E_{\alpha}$, ${\Delta}H^{\ast}$, ${\Delta}S^{\ast}$ and ${\Delta}G^{\ast}$ from Arrhenius equation were also calculated for the electrophilic 1,3-dipolar cycloaddition of 3-phenyloxadiazole derivatives with dipolarophiles. In order to the proposal the mechanism and reactivity of 1,3-dipolar cycloaddition reaction, the effect of substituents having various kinds of electron withdrawing or releasing groups were examinated. Considering the effect of substituents, an electron withdrawing group attached at the 4-carbon position in 3-phenyloxadiazole derivatives decreases the reaction rate because of the lack of electron density in 3-phenyloxadiazole ring.

• Journal of Photoscience
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• 제12권3호
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• pp.185-186
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• 2005

The electronic structure of photoskinsensitizing psoralens has been investigated by the ab initio calculations. The photocycloaddition reaction of 8-methoxypsoralen with thymine is studied as a model for the photosensitizing reaction of psoralen with DNA bases. The photocycloadduct was inferred to be a C4-cycloaddition product with the stereochemistry of Syn, H-H, Syn, H-T formed through [2+2] addition reaction between the 3,4-double bonds of 8-methoxypsoralen and 5,6-double bond of thymine base.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1403-1408
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• 2014

The cycloaddition reactions of the N-heterocyclic carbene boryl azide with methyl acrylate, butenone, and hexafluoropropene have been investigated theoretically. Solvent effects on these reactions have been explored by calculation that included a polarizable continuum model (PCM) for the solvent (C6H6). The title reaction could produce 4- and 5-substituted 1,2,3-triazolines, respectively. The reaction systems have the higher chemical reactivity with the low barriers and could be favored. Yet the smaller differences have been found to occur in energetics, and the cycloaddition reactions occur for s-trans conformations over s-cis conformations. The calculations indicated that the cycloaddition reaction of the alkenes have certain regioselectivity.

• Archives of Pharmacal Research
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• 제16권1호
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• pp.75-77
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• 1993

The cycloaddition reaction of N-phenyl-C-cinnamonitrilimine 4 to coumarin leads to the for-mation of 3-styrylbenzopyrano[4,3-c]pyrazole derivative 6, whereas 3-phenylsulfonylcoumarin 9 or 3-bromocoumain 10 or 3-cyanocoumarin 11 gives 1-styrylbenzopyrano[3,4]pyrazole derivative 7. Also, the cycloaddition of 4 to 3-acetylocoumarin 15 and 3-benzoylocumain 16 gives the corresponding dihydropyrano[3,4-c]pyrazole adducts 17 and 18 respectively. Oxidation of 17 and 18 gives 7.

• Archives of Pharmacal Research
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• 제15권4호
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• pp.292-297
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• 1992

Coupling of naphthacylpyridinium bromide 2 [1-(2-naphthyl) ethanone-2-pyridinium bromide] with N-nitrosoacetarylamides afforded C-(2-naphthoyl)-N-arylmethanohydrazonoylpyridinium bromides 3A-C. Treatment of 3A-C with base afforded the corresponding tetrazines 6A-C. Cycloaddition of nitrilimines 5A-C to N-arylmaleimides, acrylonitrile, ethyl acrylate, acrylamide, fumaronitrile, $\alpha$-cyanocinnamonitriles, ethyl $\alpha$-cyano-p-nitrocinnamates and $\alpha$-cyano-p-nitrocinnamamide afforded the corresponding cycloadducts 7-14, respectively. The cycloadducts 11-14 undergo a facile thermal elimination of hydrogen cyanide to give the corresponding pyrazoles 18-21 respectively.

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.335-339
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• 1998

Syntheses of carbapenam skeletons were achieved from 3-benzyloxypropanal through 1,3-dipolar cycloaddition. 3-Benzyloxypropanal was reacted with N-hydroxyglycine ester to give C-(2-benzyloxyethyl)-N-alkoxycarbonylmethylnitrone (6). 1,3-Dipolar cycloaddition of the nitrone with ethyl crotonate gave 3-(2-benzyloxyethyl)isoxazolidine (7). Compound 7 was transformed to 4-(2-hydroxyethyl)-2-azetidinone (11). Compound 11 was converted to 4-(2-iodoethyl)-2-azetidinone (13) or 4-phenylthiocarbonylmethyl-2-azetidinone (16) which was cyclized to give 6-(1-hydroxyethyl)carbapenam-3-carboxylate (14, 17).

• 대한화학회지
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• 제53권3호
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• pp.244-256
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• 2009

소랄렌과 피리디민 염기와의 $C_4$-고리화 부가반응을 통한 가닥내 교차 결합(interstrand crosslinking) 에 의해 만들어진 소랄렌 복합체를 ab initio 방법인 HF와 DFT 6-31G 방법을 이용하여 연구하였다. 소랄렌과 피리디민 염기에 의해 만들어진 광생성물인 8-MOP< >Thy, Ps< >Cyt, Ps< >Thy, Ps< >Ps, Thy< >(3, 4)Ps(12, 13)< >Thy의 최적화된(optimized) 구조를 알 수 있으며, 8-MOP< >Thy은 (trans-syn) 구조, Ps(3, 4)< >Cyt은 (trans-anti) 구조, Ps(12, 13)< >Cyt은 (trans-anti) 구조, Ps(3, 4)< >Thy은 (trans-syn) 구조, Ps(12, 13)< >Thy은 (trans-syn) 구조가 가장 유리하다. Ps(3, 4)< >Thy과 Ps(12, 13)< >Thy의 Gibbs 자유 에너지 변화(${\Delta}{G^{\circ}}$)를 비교하면 Ps(12, 13)< >Thy의 광생성물(단일부가 생성물)이 이루어진 뒤에 Ps(3, 4)< >Thy의 광고리화 부가반응 생성물(이중부가 생성물)을 형성한다는 사실을 알 수 있다. Bispsoralen(psoralen dimer)에서는 Ps(12, 13)< >Ps(12, 13)(trans-anti) 구조가 가장 유리하며, Thy< >(3, 4)Ps(12, 13)< >Thy에서는 (cis syn)(cis anti) 형태가 가장 유리하다.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.89-94
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• 2011

The mechanism of the cycloaddition reaction of forming germanic bis-heterocyclic compound between singlet dimethylgermylene carbene and acetone has been investigated with CCSD(T)//B3LYP/6-$31G^*$ method. From the potential energy profile, it can be predicted that, this reaction has one dominant channel. The presented rule of this dominant channel is that the two reactants firstly form a four-membered ring carbene (RC4) through the [2+2] cycloaddition reaction. Due to $sp^2$ hybridization of carbene C atom in RC4, RC4 further combines with acetone to form a reactant complexe (RC5). Due to the further $sp^3$ hybridization of carbene C atom in RC4, RC5 isomerizes to a germanic bisheterocyclic compound (P6) via the transition state (TS5).

• Bulletin of the Korean Chemical Society
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• 제17권10호
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• pp.909-918
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• 1996

Syntheses of carbapenam skeletons were achieved from 1,3-propanediol through 1,3-dipolar cycloaddition. 3-(Tetrahydropyran-2-yloxy)-(10) and 3-(t-butyldimethylsilyloxy) propanal (13) were obtained from 1,3-propanediol. 3-Hydroxypropanals (10, 13, 14) were reacted with N-hydroxyglycine esters to give C-(2-hydroxyethyl)-N-alkoxycarbonylmethylnitrones (15a-15d). 1,3-Dipolar cycloaddition of the nitrones with methyl acrylate or ethyl crotonate gave 3-(2-hydroxyethyl)isoxazolidines (16a-16b, 17a-17b, 18, 19a-19b). 3-(2-Hydroxyethyl)isoxazolidines (17a, 17c, 19a, 19b) were converted to 3-(2-iodoethyl)isoxazolidines (21a-21d) or 3-phenylthiocarbonylmethylisoxazolidines (25a-25d) which were cyclized to give 2-oxa-1-azabicyclo[3.3.0]octanedicarboxylates (22a-22d, 26a-26d). 2-Oxa-1-azabicyclo[3.3.0]octane-4,8-dicarboxylates (22c-22d, 26c-26d) were transformed to 6-(l-hydroxyethyl)carbapenam-3-carboxylates (30a-30b, 31a-31b).