• Title/Summary/Keyword: Organic chemistry

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Taxoids, Lignans, and Simple Phenolic Compounds from a Sample of the Needles of Himalayan Taxus baccata

  • Das, Biswanath;Anjani, G.;Kashinatham, A.;Venkataiah, B.;Rao, S. Padma
    • Natural Product Sciences
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    • v.4 no.2
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    • pp.78-83
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    • 1998
  • Chemical investigation on a sample of the needles of Himalayan Taxus baccata has resulted in the isolation of several taxoids including taxol (1) 10-deacetyl-baccatin III (2) and 2-deacetoxytaxinine J (3) along with different lignans (6 and 7) and simple phenolics (8, 9, 10, 11 and 12). The occurrence of 4-(4'-hydroxyphenyl)-butane-2-one and 4-(4'-hydroxyphenyl)-trans-but 3-ene-2-one (8) in Taxus species is reported for the first time. The $^{13}C-NMR$ spectral data of two rearranged taxiod constituents, brevifoliol (4) and 13-decinnamoyltaxchinin B (5) are presented. The acid-catalyzed decomposition of taxol has been discussed. The synthesis of other two constituents, rhododendrol (10) and hibalactone (7) has been described.

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Sulphamic Acid: an Efficient Catalyst for the Synthesis of α-HydroxyPhosphonates Using Ultrasound Irradiation (술팜산: 초음파 조사를 이용한 α-히드록시 인산염 합성의 효과적인 촉매)

  • Sadaphal, Sandip A.;Sonar, Swapnil S.;Pokalwar, Rajkumar U.;Shitole, Nanasaheb V.;Shingare, Murlidhar S.
    • Journal of the Korean Chemical Society
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    • v.53 no.5
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    • pp.536-541
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    • 2009
  • Sulphamic acid has been exploited as a cost-effective catalyst and green alternative for conventional acidic materials to synthesize $\alpha$-hydroxy phosphonates under solvent-free condition. The reaction carried out using ultrasound irradiation with better yields and shorter reaction time.

Microwave-Assisted Synthesis of 3-Styrylchromones in Alkaline Ionic Liquid

  • Shelke, Kiran F.;Sapkal, Suryakant B.;Shitole, Nana V.;Shingate, Bapurao B.;Shingare, Murlidhar S.
    • Bulletin of the Korean Chemical Society
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    • v.30 no.12
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    • pp.2883-2886
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    • 2009
  • A simple, highly efficient and environmentally benign method for the synthesis of 3-styrylchromones from 3-formylchromones and 4-nitrophenylacetic acid/4-nitrotolune in the presence of catalytic amount of basic ionic liquid 1-butyl-3-methylimidazolium hydroxide [(bmim)OH] carried out under the influence of microwave irradiation. This method gives remarkable advantages such as, short reaction times, simple work-up procedure and moderate to good yields. The ionic liquid was successfully reused for four cycles without significant loss of activity.

Synthetic $\beta$-Lactam Antibiotics VI. Antibacterial Activity of Some 7$\beta$[-(2-Aminothiazol-4-yl)-2-(methoxyimino)acetamido]-3-(pyrrolidinium) methylcephalosporins

  • Lim, Dong-Yeol;Kim, Kyung-Bo;Yang, Woon-Yang;Park, Sang-Woo;Kim, You-Seung
    • Archives of Pharmacal Research
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    • v.15 no.2
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    • pp.187-189
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    • 1992
  • In the preceding paper, we reported the synthessis and biological properties of cephalosporins having quinoliniumthiomethyls at the C-3 position and demonstrated that quinoliniumthiomethylcephalosporins exhibited an extended antibacterial spectrum including antipseudomonal activity, especially strong antiGram-positive activity. With the aim of elaboration to optimize the antibacterial potency of the quaternary ammonium cephalosporins, we have studied the modification of substituents in the pyrrolidine ring of cefepime 1 which is characterized by its potent activity.

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An Effective Acylation of Cephalosporins Using 1-Methanesulfonyloxy-6-trifluoromethylbenzotriazole$^\dag$

  • Lee, Cheol-Hae;Moon, Chi-Jang;Kim, Kyeong-Sook;Kim, Jae-Hak;Kim, Dae-Whang
    • Bulletin of the Korean Chemical Society
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    • v.8 no.4
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    • pp.336-338
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    • 1987
  • A new coupling agent, 1-methanesulfonyloxy-6-trifluoromethyl-benzotriazole (3), was prepared by the reaction of 1-hydroxy-6-trifluoromethylbenzotriazole (1) and methanesulfonyl chloride. 3 was reacted with 2-(2-amino-4-thiazolyl)-2-synalkoxyi minoacetic acid (4) to give a mixture of active intermediates (5 and 6), which was treated with 7-aminocephalosporanic acid derivatives (10) to afford cephalosporin derivatives (11) in short reaction time with high yields.