• Title/Summary/Keyword: reductive desulfurization

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Synthesis of 2-(2-Fluorenyl)propanoic Acid

  • Choi, Hong-Dae;Geum, Dek-Hyun;Kowak, Young-Sil;Son, Byeng-Wha
    • Archives of Pharmacal Research
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    • v.17 no.1
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    • pp.17-20
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    • 1994
  • Friedel-Crafts reaction of fluorene with methyl ${\alpha}$-chloro-${\alpha}$-(methylthio)acetate 1 gave methyl $\alpha$-methylthio-2-fluoreneacetate 2. Cicloprofen 8, a potent antiinflammatory agent, was prepared by methylation of 2 followed by reductive desulfurization of methyl 2(2-fluorenyl)-2-(methylthio)propionate 6 and hydrolysis of methyl 2-(2-fluorenyl)propionate 7.

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Synthesis of p-(Acetylamino)phenylacetic acid As an Antirheumatic Agent (항류우머티즘 물질인 p-(아세틸아미노)페닐아세트산의 합성)

  • Choi, Hong-Dae;Son, Byung-Wha
    • YAKHAK HOEJI
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    • v.41 no.4
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    • pp.480-483
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    • 1997
  • The efficient synthesis of p-(acetylamino)phenylacetic acid(7), a antirheumatic agent, is reported. Methyl phenylacetate(3) was prepared from Friedel- Crafts reaction of benzene with methyl ${\alpha}$-chloro-${\alpha}$-(methylthio)acetate(1) followed by reductive desulfurization with zinc dust in acetic acid. Compound(7) was obtained from 3 by a sequence of nitration, reduction, N-acylation, and hydrolysis.

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Synthesis of 5-(p-Toluoyl)-1-Methylpyrrole-2-Acetic Acid [Tolmetin] (5-(p-톨루오일)-1-메틸피롤-2-아세트산의 합성)

  • Choi, Hong-Dae;Ma, Jung-Joo
    • YAKHAK HOEJI
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    • v.36 no.4
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    • pp.341-344
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    • 1992
  • A facile method for tolmetin, which is a potent antiinflammatory agent, is described. Friedel-Crafts reaction of 1-methylpyrrole with ethyl ${\alpha}-chloro-{\alpha}-(methylthio)acetate$ (1) gave ethyl ${\alpha}-methylthio$-1-methyl-2-pyrroleacetate (4), which was readily converted into ethyl 1-methyl-2-pyrroleacetate (5) by reductive desulfurization with zinc dust in acetic acid. Tolmetin was synthesized by Friedel-Crafts acylation of (5) with p-toluoyl chloride, followed by hydrolysis of the resultant ethyl 5-(p-toluoyl)-1-methylpyrrole-2-acetate (6).

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Synthesis of Ibuproxam (Ibuproxam의 합성)

  • 최홍대;마정주
    • YAKHAK HOEJI
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    • v.35 no.2
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    • pp.119-122
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    • 1991
  • A convenient method for the synthesis of ibuproxam, which is a non steroidal antiinflammatory agent, is reported. Friedel-Crafts reaction of isobutylbenzene with ethyl $\alpha$-chloro-$\alpha$-(methylthio)acetate (3) gives ethyl $\alpha$-methylthio-(p-isobutylpheny) acetate (4). Ethyl 2-methylthio-2-(4-isobutylphenyl) propionate (5) is obtained from methylation of the compound (4) with NaH and Mel. lbuproxam (7) is easily synthesized by reductive desulfurization of the compound (5) with zinc dust-acetic acid or Raney nickel, followed by treatment of the resultant ethyl 2-(4-isobutyl-pheny) propionate (6) with H$_{2}$NOH-HCI.

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Synthesis of Butibufen (Butibufen의 합성)

  • 최홍대;마정주
    • YAKHAK HOEJI
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    • v.35 no.2
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    • pp.131-134
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    • 1991
  • A new method for the synthesis of butibufen, which is a non steroidal anti-iriflammatory agent, is described. Friedel-Crafts reaction of isobutylbenzene with ethyl $\alpha$-chloro-.alpha.-(methylthio) acetate (1) gives ethyl $\alpha$-methylthio-(p-isobutylphenyl)acetate (2). Ethyl 2-methylthio-2-(4-isobutylphenyl)butyrate (3) is obtained from treatment of the compound (2) with NaH and Etl. Butibufen (5) is synthesized by reductive desulfurization of the compound (3) with zinc dust-acetic acid or Raney nickel, followed by hydrolysis of the resultant ethyl 2-(4-isobutylphenyl)butyrate (4).

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An Improved Synthesis of Methyl p-Hydroxyphenylalkanoates

  • Choi, Hong-Dae;Kowak, Yong-Sil;Geum, Dak-Hyun;Son, Byeng-Wha
    • Archives of Pharmacal Research
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    • v.17 no.3
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    • pp.190-193
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    • 1994
  • Friedel-Crafts reaction isopropoxybenzene with methyl $\alpha$-chloro-$\alpha$-(maethylthio)acetate 1 afforded methyl $\alpha$-methylthio-p-isopropoxyphenylacetate 2d, which was readily converted into methyl p-isopropoxyphenylacetate 3 by reductive desulfurization with zinc dust in acetic acid. Methylation of 3 with sodium hydride and methyl iodide gave methyl $\alpha$-(p-isopropoxyphenyl)propionate 5. Methyl p-hydroxyphenylakanoates (4,6), useful intermediates for some medicines, were easily prepared by treatment of 3 and 5 with titanium tetrachloride, respectively.

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Total Synthesis of a Norneolignan from Ratanhia Radix

  • Choi, Hong-Daei;Seo, Pil-Ja;Son, Byeng-Wha
    • Archives of Pharmacal Research
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    • v.25 no.6
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    • pp.786-789
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    • 2002
  • The total synthesis of a norneolignan isolated from Ratanhia, 5-(3-hydroxypropyl)-2-(2'-methoxy-4'-hydroxyphenyl)benzofuran (8), is described. The key steps contain the one-pot reaction for a 2-arylbenzofuran 6 from methyl 3-(4-hydroxyphenyl)propionate with 2-chloro-2-methylthio-(2'-methoxy-4'-acetoxy)acetophenone (5) in the presence of $ZnCl_2$, and reductive desulfurization of the resulting product 6.