• 제목/요약/키워드: cycloaddition

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Synthetic Studies on Carbapenam Skeletons

  • 구양모;서민효;이윤영
    • 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).

Efficient One-Step Synthesis of 2-Arylfurans by Ceric Ammonium Nitrate (CAN)-Mediated Cycloaddition of 1,3-Dicarbonyl Compounds to Alkynes

  • 이용록;변명환;김병소
    • Bulletin of the Korean Chemical Society
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    • 제19권10호
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    • pp.1080-1083
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    • 1998
  • An efficient method for construction of 2-arylfiirans has been developed by ceric(IV) ammonium nitratemediated oxidative cycloaddition of cyclic and acyclic 1,3-dicarbonyl compounds to several alkynes. Reactions of 1,3-cyclohexanedione, 1,3-cyclopentanedione, and 2,4-pentanedione with several alkynes furnish 2-arylfurans in 26-75% yields. Extension of this technology to more complex 4-hydroxy-2-quinolone and 3-hydroxy-lH-phenalen-l-one with phenylacetylene also affords furoquinolinone and ftirophenalenone derivative in moderate yields. Reaction of 4-hydroxycoumarins with phenylacetylene give linear and angular furocoumarin derivatives as a mixture of regioisomer in good yields. The mechanistic pathway for the formation of 2-arylfurans has been also described.

Kinetics of the 1,3-dipolar Cycloaddition of p-substituted 3-phenylsydnones with DMAD

  • Youn, Byoung-Hee;Lyu, Hak-Soo;Han, Jee-Hyun;Hahn, Soon-Jong;Kim, Sun-Hwan
    • Bulletin of the Korean Chemical Society
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    • 제8권4호
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    • pp.233-235
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    • 1987
  • The kinetics of the 1,3-dipolar cycloaddition of p-substituted 3-phenylsydnones 1a-d with DMAD have been investigated. The reaction rates over a temperature range $100-140^{\circ}C$ were measured by UV spectrometry. The reactions found to be second-order overall, insensitive to the dielectric constants of the solvents, and characterized by a large entropy of activation. These findings are consistent with the rate-determining step involving the formation of cyclic transition state 1 and the reaction proposed to be concerted.

Diastereomeric Strain-Promoted Azide-Alkyne Cycloaddition: determination of configuration with the 2D NMR techniques

  • Hye Jin Jeong
    • 한국자기공명학회논문지
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    • 제27권2호
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    • pp.10-15
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    • 2023
  • The Strain-Promoted Azide-Alkyne Cycloaddition (SPAAC) is a powerful method for synthesizing triazoles, even under physiological conditions, without a copper catalyst. This technique provides an efficient means for everyone to synthesize complex triazole derivatives rapidly. In order to investigate the configuration of triazole derivatives using bicyclo[6.1.0.]-nonyne (BCN) and chiral azide, it is necessary to employ the 2D NMR. Both 1D and 2D NMR (COSY, HSQC, 15N HMBC) are used to analyze the complex triazole product containing cyclooctyne, a diastereomeric product. The stereometric difference of the proton bonded to the same carbon is determined through the HSQC assignment. The intriguing splitting pattern of carbon resonances also reveals their diastereomeric configuration and will aid in further research based on physiological knowledge.

Regioselective Synthesis of [1]Benzopyrano [4,3-c]pyrazol-4-(1H)-one and [1]Benzopyrano[3,4-c]pyrazol-4(3H)-one Derivatives

  • Hassaneen, Hamdi M.;Shawali, Ahmad S.;Algharib, Mohammed S.;Elwan, Nehal M.
    • 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.

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Synthesis and Cycloaddition Reaction of C-(2-naphthoyl)-N-arylmethanohydrazonoylpyridinium Bromides

  • Hassaneen, Hamdi M.;Shawali, Ahmad S.;Elwan, Nehal M.;Abounada, Nada M.;Algharib, Mohammed S.
    • 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.

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