• Title/Summary/Keyword: bromo

Search Result 330, Processing Time 0.023 seconds

Synthesis of 2,4-Dienoic Acid Derivatives by Palladium Catalyzed Homogeneous Reaction (팔라듐 촉매 균일계 반응을 이용한 2,4-디엔산 유도체의 합성)

  • Jin Il Kim
    • Journal of the Korean Chemical Society
    • /
    • v.27 no.6
    • /
    • pp.441-448
    • /
    • 1983
  • A wide variety of vinylic bromides such as (Z)-1-bromopropene, 1-bromo-2-methylpropene, 2-bromo-3-methyl-2-butene, (E)-ethyl 2-methyl-3-bromo-2-propenoate, 1-bromo-cyclohexene has been found to react with ethyl acrylate, ethyl 3-butenoate, allyl cyanide, (E)-ethyl crotonate, ethyl 4-pentenoate, methyl 10-undecenoate and methyl methacrylate in the presence of triethylamine and a palladium acetate-triorthotolylphosphine catalyst. In general, 2,4-dienoic acid derivatives were obtained in good yield and stereochemistry of the products was determined. Using this method, four, five and eleven carbon-carbon extension with ethyl 3-butenoate, ethyl 4-pentenoate and methyl 10-undecenoate was also possible.

  • PDF

Determination of Urinary Metabolite of Profenofos after Oral Administration and Dermal Application to Rats (흰쥐를 이용한 profenofos의 경구투여 및 피부도포 후 뇨 중 대사물질 측정)

  • 민경진;조영주;이인선;차춘근
    • Journal of Food Hygiene and Safety
    • /
    • v.17 no.1
    • /
    • pp.20-25
    • /
    • 2002
  • This study was aimed to determine the urinary metabolite of profenofos, one of the organophos-phorus pesticides, as the biomarkers of exposure. Urine samples were collected fort 24 hours in metabolic cages after oral administration and dermal application of profenofos to rats. Identification of the derivatized urinary metabolite was determined by GC/MS and excretion time courses of the urinary metabolite was analyzed by GC/MS. Urinary metabolite of profenofos, 4-bromo-2-chlorophenol, was detected in rats urine both after oral administration and dermal application of profenofos. Parent compound was not detected in the experiment. In GC/MS, the mass spectral confirmation for 4-bromo-2-chlorophenol ion was identified at m/z 208.4-bromo-2-chlorophenol was excreted within 48 hours and 72 hours after oral administration and dermal application of profenofos, respectively. In this study, the same urinary metabolite of profenofos was detected both in oral and dermal exposure. Generally, excretion of the urinary metabolite after oral administration was detected faster than after dermal application. It is suggested that urinary 4-bromo-2-chlorophenol could be used as the biomarkers of exposure to profenofos.

Bromolactonization of 2-Substituted-1-Cyclohexenyl-1-acetic acid (2-치환-1-Cyclohexenyl-1-acetic acid의 브롬락톤화 반응)

  • Jew, Sang-Sup
    • YAKHAK HOEJI
    • /
    • v.33 no.3
    • /
    • pp.206-210
    • /
    • 1989
  • Bromolactonization of 2-Substituted-1-cyclohexenyl-1-acetic acid (1) with 1,3-dibromo-5,5-dimethylhydantoin (dibromantin) in N,N-dimethylformamide gave the corresponding ${\gamma}-bromo-{\beta}-lactone$ (2) and ${\beta}-bromo-{\gamma}-lactone$ (3). The effect of the substituents, the reaction temperature, and the solvent on the regioselectivity was discussed.

  • PDF

Total Synthesis of (±)-Aspidospermidine Starting from 3-Ethyl-5-bromo-2-pyrone

  • Cho, Hyun-Kyu;Tam, Nguyen Thanh;Cho, Cheon-Gyu
    • Bulletin of the Korean Chemical Society
    • /
    • v.31 no.11
    • /
    • pp.3382-3384
    • /
    • 2010
  • A new synthetic route to ($\pm$)-aspidospermidine was devised, starting from the cycloadduct of 3-ethyl-5-bromo-2-pyrone with vinyl sulfide through a tandem conjugate addition-alkylation sequence. The requisite 3-ethyl-5-bromo-2-pyrone was prepared via the C3-selective Pd-catalyzed coupling reaction with $Et_3Al$-dimethylaminoethanol complex.

A novel bromolactonization reaction using racemic 2-bromo-5-isobutyl-5-methylhydantoin

  • Cho, Youn-Sang;Jew, Sang-Sup;Chung, You-sup
    • Archives of Pharmacal Research
    • /
    • v.5 no.2
    • /
    • pp.93-96
    • /
    • 1982
  • By using recemic 3-bromo-5-isobutyl-5-methylhydantoin (3a') in dry N, N-dimethylformamide which is a model reagent for asymmetric bromolactonization, bromolactonization of a series of olefinic acids was carried out to furnish corresponding bromolactones in moderate yields.

  • PDF

Dynamic Resolution of α-Bromo Tertiary Amides for Stereoselective Preparation of Dipeptide Analogues

  • Kim, Hyun-Jung;Chang, Ji-Yeon;Shin, Eun-Kyoung;Park, Yong-Sun
    • Bulletin of the Korean Chemical Society
    • /
    • v.26 no.2
    • /
    • pp.273-277
    • /
    • 2005
  • Dynamic resolution of $\alpha$-bromo tertiary acetamides in asymmetric nucleophilic substitution reaction is described. Intermolecular substitution of $\alpha$-bromo tertiary acetamides with dibenzylamine in the presence of TBAI and $Et_3N$ gave the dipeptide analogues 7-10 with high stereoselectivities up to 90 : 10 dr. Also, cyclic dipeptide analogues 20-29 were produced by the intramolecular nucleophilic cyclization of $\alpha$-bromo tertiary acetamides with low stereoselectivities in 84-42% yields.