• Title/Summary/Keyword: Halogenation

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Halogenation of Cannabinoids (Cannabinoid의 할로겐화)

  • Baek Seung-Hwa;Park No-Yeun
    • Journal of the Korean Chemical Society
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    • v.35 no.1
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    • pp.59-63
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    • 1991
  • Several types of cannabinoids have been halogenated in the aromatic ring in good yields with metal halide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. This reagent system effects the regiospecific halogenation of activated aromatic ring over olefinic double bond.

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Halogenation of Resorcinol Derivatives

  • Baek Seung-Hwa
    • Bulletin of the Korean Chemical Society
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    • v.9 no.1
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    • pp.13-15
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    • 1988
  • Several types of resocinols have been monobrominated in the ring in good yields with sodium bromide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. Monoiodination takes place with 2'-(1-methylcyclohexen-3-yl)-5-(1,1-dimethylheptyl )-resocinol when sodium iodide is employed. This new reagent system, MX/18-crown-6/m-CPBA (M =$K^+, Na^+, X = Br^-, I^-X$ ), effects the regiospecific halogenation of activated aromatic ring over olefinic double bond.

Halogenation of Aldehydes and Ketones by Selenium (IV) Oxyhalides Generated in-situ from Selenium Dioxide and Halotrimethylsilanes

  • 이종근;박인수;서종화
    • Bulletin of the Korean Chemical Society
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    • v.16 no.4
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    • pp.349-355
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    • 1995
  • Bromo-and chlorotrimethylsilane react with selenium dioxide in halocarbon solvents and generate selenium oxybromide and oxychloride, respectively. These in-situ generated oxyhalides turned out to be very efficient for selective bromination and chlorination of aldehydes and ketones. Under carefully controlled reaction conditions, second and third introduction of halogens into carbonyl compounds can be greatly suppressed, and high yields of monohalo compounds were obtained. The product ratios of this halogenation reactions can be best explained if the reactions are assumed to involve intermediate β-ketoselenenyl chlorides.

Halogen Containing Heterocyclic Compounds (Part Ⅱ) Halogenation of Furfuryl Derivatives-Maleic Anhydride Adduct (含할로겐 異元素環化合物에 關한 硏究 (第2報) 풀퍼릴誘導體-마레인酸無水物 附加物의 할로겐化反應)

  • Kim, You-Sun;Kim, Chung-Hee
    • Journal of the Korean Chemical Society
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    • v.9 no.2
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    • pp.88-95
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    • 1965
  • The exo adduct between furfuryl derivatives (furan, furfuryl acetate and furfuryl alcohol) and maleic anhydride were prepared in the presence of ethyl ether. The bromination of the exo adduct of each derivatives gave a monobromolactone and dibromoacid when the reaction was done in the presence of water. The formation of the bromolactone was proved to be dependent to the carboxylic participation to the incipient rearranged carbonium ion of a classical type, and the participation was sterically hindered by the steric structure of the substituents. The bromination of the furan-maleic anhydride adduct in the presence of organic solvent $(CCl_4,\;CH_2Cl_2)$ gave the dibromide, whereas the photochlorination of the same adduct in the presence of carbon tetrachloride gave the tetrachloride. The procedure of the preparation and the reaction path of the halogenation were described.

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Pseudohalogenation and Halogenation of Indole Derivativs(II) - A Novel Synthetic Method of Azido and Thiocyanato Indoles (인돌 유도체의 Pseudohalogen 화 및 Halogen 화 반응에 관한 연구(II) - 인돌의 Azido 및 Thiocyanato 유도체의 새로운 합성법)

  • 채동규;천문우;조재천
    • YAKHAK HOEJI
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    • v.23 no.3_4
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    • pp.187-189
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    • 1979
  • A new method for the synthesis of azido and thiocyanatoindoles by iodine and sodium azide or sodium thiocyanate in acetonitile at room temperature or 60.deg.C was found. Azidoindoles (3-azido-3-methyl -2-phenylindolenine, 3-azido-2,3-diphenylindolenine, 2-azidomethyl-3-metbylindole and 1-azido-1,2,3,4-tetrahyrocarbazole) and thiocyanatoindoles(3-thiocyanatoindole, 2-phenyl-3-thiocyanato indole, 3-methyl-2-phenyl-6-thiocyanatoindole and 2, 3-diphenyl-6-thiocyanatoindole) were prepared by this method in good yields.

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Change of Sponge(Axinella sp.)-Associated Bacterial Community during the Cultivation with Hexabromobenzene (Hexabromobenzens 농후 배양에 따른 해면(Axinella sp.) 공생 미생물의 군집구조 변화)

  • Seo, Hyun-Seok;Yang, Sung-Hyun;Bae, Seung Seob;Lee, Jung-Hyun;Kwon, Kae Kyoung
    • Journal of Marine Bioscience and Biotechnology
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    • v.6 no.2
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    • pp.76-83
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    • 2014
  • Bacteria associated with marine sponges seemed to be concerned in halogenation/dehalogenation process of natural compounds. In the present study, the effect of hexabromobenzene (HBB) on the community structure of bacteria associated with a marine sponge Axinella sp. from Chuuk State under anaerobic condition was investigated. Regardless of 100 ppm HBB, most of detected microorganisms displayed high similarity with clones reported from coral or sponges. Amongst, Desulfovibrio marinisediminis like clones were dominant. Clones affiliated with Lentisphaerae and Fusibacter paucivorans (Clostridia) were detected at the conditions without HBB but clones affiliated with Vallitalea guaymasensis (Clostridia) increased its proportion with HBB. From these results and previous reports clones affiliated with D. marinisediminis and V. guaymasensis seemed to be concerned in halogenation/dehalogenation process.

An Efficient Synthesis of Substituted Furans by Cupric Halide-Mediated Intramolecular Halocyclization of 2-(1-Alkynyl)-2-alken-1-ones

  • Fu, Wei-Jun;Xu, Feng-Juan;Guo, Wen-Bo;Zhu, Mei;Xu, Chen
    • Bulletin of the Korean Chemical Society
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    • v.34 no.3
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    • pp.887-891
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    • 2013
  • An efficient synthesis of 3-halofurans by the intramolecular cyclization of 2-(1-alkynyl)-2-alken-1-ones with cupric halide has been developed. A broad range of 3-chloro- and 3-bromofuran derivatives could be obtained in the present method in moderate to good yields. The 3-halofuran derivatives are potential synthetic intermediates for amplification of molecular complexity.