• Title/Summary/Keyword: Claisen rearrangement

Search Result 36, Processing Time 0.02 seconds

Synthesis of 4′$\alpha$-C Methyl Branched Novel Adenine and Uracil Carbocyclic Nucleosides Using Ring-Closing Metathesis (Ring-Closing Metathesis 반응을 이용한 새로운 4-메칠 아데닌 및 유라실 카보사이클릭 뉴크레오사이드의 합성)

  • 홍준희
    • YAKHAK HOEJI
    • /
    • v.47 no.5
    • /
    • pp.271-275
    • /
    • 2003
  • Easy and efficient synthetic route of novel 4'-C methyl branched carbocyclic nucleosides is described. The installation of alkyl and aryl groups at 4'-position of carbocyclic nucleosides were successfully made via sequential [3,3]-sigmatropic rearrangement and ring-closing metathesis (RCM) starting from simple ketones such as acetol. Adenine and uracil were coupled via Pd(0) catalyzed reaction, followed by desilylation to give novel compounds 13 and 14, respectively.

Synthesis of Permethrin using Ester Enolate Claisen Rearrangement (에스테르엔올 음이온의 Claisen 자리옮김 반응에 의한 Permethrin의 합성)

  • In-Kyu Kim;Suk-Ku Kang;Jang-Hoo Hong
    • Journal of the Korean Chemical Society
    • /
    • v.30 no.6
    • /
    • pp.548-552
    • /
    • 1986
  • A stereoselective synthesis of 3-phenoxybenzyl (${\pm}$)-cis and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid starting from readily available 2-methyl-3-buten-2-ol($\underline{2}$) is described. Allylic rearrangement of 2-methyl-3-buten-2-ol, in the presence of acetic acid and acetic anhydride gave 3-methyl-2-butenyl acetate($\underline{3}$). The [3,3] sigmatropic rearrangement of the allyl acetate($\underline{3}$), as the silylketene acetal, produced the ${\gamma},\;{\delta}$-unsaturated acid($\underline{4}$). Treatment of 3,3-dimethyl-4-pentenoic acid($\underline{4}$) with SOCl2 followed by esterification with 3-phenoxybenzyl alcohol yielded 3, 3-dimethyl-4-pentenoic acid ester($\underline{5}$). Addition of carbon tetrachloride to the olefin ester($\underline{6}$) furnished 4,6,6,6-tetrachloro-3,3-dimethylhexanoic acid ester ($\underline{7}$). Cyclization with potassium t-butoxide and elimination of hydrogen chloride afforded 3-phenoxybenzyl (${\pm}$) cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid.

  • PDF

Simple Synthesis of Novel 1',4'-Dimethyl Branched Carbovir Analogues

  • Kim, Ai-Hong;Hong, Joon-Hee
    • Bulletin of the Korean Chemical Society
    • /
    • v.26 no.11
    • /
    • pp.1767-1770
    • /
    • 2005
  • Novel 1',4'-dimethyl branched carbocyclic nucleosides were synthesized from acetol. The 4'-methyl group was installed via a Claisen rearrangement reaction, and the carbonyl addition of methylmagnesium bromide was used to introduce the 1'-methyl group. The coupling of nucleosidic bases and desilylation was used to produce a series of novel nucleosides.

Enantiomeric Synthesis of Novel Apiosyl Nucleosides as Potential Antiviral Agents

  • Kim, Ai-Hong;Hong, Joon-Hee
    • Bulletin of the Korean Chemical Society
    • /
    • v.25 no.2
    • /
    • pp.221-225
    • /
    • 2004
  • A series of 2',3'-dideoxy-3'-fluoro-D-apiosyl nucleosides 15, 16, 17 and 18 were synthesized enantiomerically with L-Gulonic- ${\gamma}$-lactone as the starting material. The reduction of butenolide 1 with DIBAL-H followed by the Luche procedure afforded the allylic alcohol 2. Ozonolysis and the reduction of compound 4 induced the cyclized lactol, which was acetylated to give the acetate 7. Condensation of the acetate 7 with silylated pyrimidine ($N^4$-benzoyl cytosine) and a purine base (6-chloropurine) under Vorbruggen conditions and deblocking afforded a series of fluorinated apiosyl nucleosides.