• Title/Summary/Keyword: Diketene

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Phosgen-free Synthesis of Oligoureas Having Amino End-groups: Their Application to the Synthesis of Poly(urea-imide)

  • Chang, Ji-Young;Kim, Beom-Jin
    • Fibers and Polymers
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    • v.3 no.2
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    • pp.55-59
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    • 2002
  • The thermal reaction of acetoacetanilide in the presence of aniline or phenol yielded carbanilide in quantitative yields. This reaction was applied to the synthesis of polyurea. Bisacetoacetamides were prepared from diamines and diketene in DMF. They were thermally polymerized in the presence of phenol or a diamine (6FDA) to yield polyureas of low molecular weights. The polymers were soluble in DMSO and NMP. $^1{H-NMR}$ analysis showed that they had amino group terminated structures. Poly(urea-imide) was synthesized by the reaction of an oligourea diamine with pyromellitic dianhydride in NMP. The concentration of terminal amino groups was determined by an acid-base titration. The thermal property of poly(urea-imide) was evaluated by thermogravimetric analysis (TGA). Initial decompisition took place at 332-$350^{\circ}C$.

Synthesis of 2-phenylimino-1,3-thiazoline hydrochloride salts (2-Phenylimino-1,3-thiazoline 염산염 유도체의 합성)

  • Hahn, Hoh-Gyu;Nam, Kee-Dal;Shin, Sun-Ho;Mah, He-Duck
    • The Korean Journal of Pesticide Science
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    • v.5 no.2
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    • pp.13-17
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    • 2001
  • A synthesis of new 2-phenylimino-1,3-thiazolines 2 for the purpose of development of new agrochemical fuugicide was described. Reaction of chlorine with diketene followed by treatment of benzylamine without isolation of intermediate 8a gave ${\gamma}-chloro-{\beta}-keto$ benzylamide 10a. Thioureas 4 obtained from the reaction of methyl isothiocyanate with aniline derivatives were subjected to 10a in acetone solution to afford the corresponding 2-phenylimino-1,3-thiazoline hydrochloric acid salts 2 through unisolable inltermediates 11 and 12. The plausible reaction mechanism including nucleophilic attack of sulfur assisted neighboring nitrogen lone pair electron on phenyl of thiourea 4 was discussed.

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A Synthesis of New 2-Iminothiazolines and Their Antifungal Activities (II) (새로운 2-이미노티아졸린 유도체의 합성과 항균활성 (II))

  • Nam, Kee-Dal;Choi, Gyung-Ja;Cho, Kwang-Yun;Hahn, Hoh-Gyu
    • Applied Biological Chemistry
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    • v.41 no.6
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    • pp.471-476
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    • 1998
  • A synthesis and the screening of new 2-iminothiazolines (IV) of which structures are modified based on a lead compound, thiazoline for development of new agrochemical fungicide were described. Bromination of acetoacetanilides (I) which were prepared by the reaction of diketene with anilines gave the corresponding ${\gamma}-bromoacetoactanilide\;(II)$. Treatment of II with N-phenyl-N'-methyl thiourea (III) afforded IV, structure of which was confirmed by various spectroscopic methods. Antifungal activity of the new IV was tested against six kinds of typical plant diseases (in vivo). The IV with aromatic substituents showed remarkable activity against the Pyricuraria oryzae at 250 ppm in primary screening. The candidates with control value over 90% in primary screening were selected and further tested for second screening at lower concentrations. The IV which has an electron-withdrawing substituent such as halogen, especially fluorine in aryl group showed a higher activity as compared to those with electron-donating group and meta substituent was for optimal position.

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