• Title/Summary/Keyword: Efficient cyclization

검색결과 39건 처리시간 0.02초

7,8번 위치에 이중결합을 갖는 10-membered lactone의 효율적인 합성 (Efficient Synthesis of 10-Membered Lactone Possessing Ring-olefin at 7,8-Position)

  • 서영거;이지연;조윤상
    • 약학회지
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    • 제39권1호
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    • pp.31-35
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    • 1995
  • An unusual 10-membered lactone possesing ring-olefin at 7, 8-position has been efficiently synthesized. The $\omega$-hydroxy acid as a cyclization precusor was derived from $\varepsilon$-caprolactone in 41% overall yield of 7 steps and efficiently cyclized by Mukaiyama procedure.

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An Efficient Synthesis of Substituted Quinolines via Indium(III) Chloride Catalyzed Reaction of Imines with Alkynes

  • Zhu, Mei;Fu, Weijun;Xun, Chen;Zou, Guanglong
    • Bulletin of the Korean Chemical Society
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    • 제33권1호
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    • pp.43-47
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    • 2012
  • An efficient synthetic method for the preparation of quinolines through indium(III) chloride-catalyzed tandem addition-cyclization-oxidation reactions of imines with alkynes was developed. The processes can provide a diverse range of quinoline derivatives in good yields from simple imines and alkynes.

New Efficient Synthesis of 3-Carboxylquinolines

  • Kirankumar, S.;Rambabu, D.;Sekhar, N. Chandra;Prasad, A.S.G.;Rao, M.V. Basaveswara
    • 대한화학회지
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    • 제56권3호
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    • pp.322-327
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    • 2012
  • Rapid and efficient synthesis of substituted 3-carboxylquinoline derivatives from 4-chloro-3-formylcoumarin and substituted anilines using 30% $H_2SO_4$ in methanol at room temperature within the duration of 5-30 min., through domino condensation-cyclization-ring opening reaction.

An Efficient Solid-phase Parallel Synthesis of 2-Amino and 2-Amidobenzo[d]oxazole Derivatives via Cyclization Reactions of 2-Hydroxyphenylthiourea Resin

  • Jung, Se-Lin;Kim, Seul-Gi;Lee, Gee-Hyung;Gong, Young-Dae
    • Bulletin of the Korean Chemical Society
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    • 제33권12호
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    • pp.4109-4116
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    • 2012
  • An efficient solid-phase methodology has been developed for the synthesis of 2-amino and 2-amidobenzo[d]-oxazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo-[d]oxazole resins 4 by cyclization reaction of 2-hydroxy-phenylthiourea resin 3. The resin-bound 2-hydroxyphenylthiourea 3 is produced by the addition of 2-aminophenol to the isothiocyanate-terminated resin 2 and serve as a key intermediate for the linker resin. This core skeleton 2-aminobenzo[d]oxazole resin 4 undergoes functionalization reaction with various electrophiles, such as alkylhalides and acid chlorides to generate 2-amino and 2-amidobenzo[d]oxazole resins 5 and 6 respectively. Finally, 2-amino and 2-amidobenzo[d]oxazole derivatives 7 and 8 are then generated in good yields and purities by cleavage of the respective resins 5 and 6 under trifluoroacetic acid (TFA) in dichloromethane ($CH_2Cl_2$).

Photocyclization Reactions of N-(Trimethylsilylmethoxyalkyl)Phthalimides. Efficient and Regioselective Route to Heterocycles

  • Yoon Ung Chan;Oh Ju Hee;Lee, Sang Jin;Kim, Dong Uk;Lee, Jong Gun;Kang Kyung-Tae;Mariano Patrick S.
    • Bulletin of the Korean Chemical Society
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    • 제13권2호
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    • pp.166-172
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    • 1992
  • Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethoxyalkyl)phthalimides(alkyl=E thyl, n-propyl, n-butyl, n-pentyl, and n-octyl). Photocyclizations occur in methanol in high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from oxygen in the $\alpha-silylmethoxy$ groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate $\alpha-silylmethoxy$ cation radicals and cyclization by radical coupling are proposed. In contrast, photoreaction of N-(trimethylsilylmethoxyethyl) phthalimide in acetone follows different reaction routes to produce two cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon $\alpha$ to silicon and oxygen atoms via triplet carbonyl hydrogen abstraction triplet carbonyl silyl group abstraction pathways. The normal singlet SET pathway dominates these triplet processes for photoreaction of this substance in methanol. The efficient and regioselective cyclization reactions observed for photolysis in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.