• Title/Summary/Keyword: 2-imino-1,3-thiazoline

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Synthesis of 2-Cyanoimino-1,3-thiazoline (2-Cyanoimino-1,3-thiazoline 유도체의 합성)

  • Hahn, Hoh-Gyu;Nam, Kee-Dal;Park, Ik-Kyu;Mah, He-Duck
    • The Korean Journal of Pesticide Science
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    • v.7 no.2
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    • pp.155-158
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    • 2003
  • 2-Imino-1,3-thiazolines 1 show selective antifungal activity against pyricularia oryzae by new mode of action. A synthesis of novel 2-cyano-l,3-thiazolines 2 in which cyano moiety is substituted in imino group at C-2 of 1 is described. The lone pair electrons of sulfur and nitrogen as well as strong electron withdrawing cyano substituent in 1,3-thiazoline scaffold would effect the biological activity of 2-imino-1,3-thiazoline series. Regiospecific nucleophilic attack of thiourea 4 for $\gamma$-chloro-$\beta$-ketoacetoacetanilide 3 followed by acid catalyzed dehydration gave 2.

Lead optimization of 2-imino-1,3-thiazolines and in vivo antifungal activity against rice blast (I) (2-이미노-1,3-티아졸린 유도체의 최적화 및 벼 도열병에 대한 방제활성 (I))

  • Hahn, Hoh-Gyu;Nam, Kee-Dal;Bae, Su-Yeal;Park, Ik-Kyu
    • The Korean Journal of Pesticide Science
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    • v.8 no.3
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    • pp.168-174
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    • 2004
  • In a course of the process for a lead optimization of 2-imino-l,3-thiazolines 1 which show a selective in vivo antifungal activity against rice blast, new compounds 2 in which C-5 was substituted by methyl group of the lead compound were synthesized and tested for the biological activity. Bromination of $\beta$-keto ester 7 followed by the reaction with thiourea and hydrolysis gave 2-imino-5-methyl-l,3-thiazoline carboxylic acid 3. Coupling reactions of 3 with aniline derivatives afforded 17 kinds of the corresponding 2-imino-5-methyl-l,3-thiazoline carboxanilides 2. Their in vivo antifungal activity against rice blast was weaker than that of 1, indicating that the in vivo antifungal activity of 2-imino-l,3-thiazolines was affected by the substituent at C-5. These results would be an important data for the molecular design in the lead optimization process of this series.

Design of new 1,3-thiazoline derivatives by isosterism and antifungal activity of new 2,4-diimino-1,3-thiazolidines (Isosterism을 이용한 새로운 1,3-thiazoline 유도체의 디자인 및 신규 2,4-diimino-1,3-thiazolidine 유도체의 살균 활성)

  • Hahn, Hoh-Gyu;Nam, Kee-Dal;Lim, Chul-Soo;Mah, He-Duck;Kim, Jin-Cheol;Cho, Kwang-Yun
    • The Korean Journal of Pesticide Science
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    • v.7 no.1
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    • pp.51-57
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    • 2003
  • For the purpose of a development of new agrochemical fungicides, new compound 4 in which 1,3-thiazoline scaffold as well as urea moiety in the structure was designed through molecular modification of lead compound, 2-imino-1,3-thiazone based on isosterism. The reaction of N-alkylthiourea 5 and bromoacetonitrile in ethanol gave 2,4-diimino-1,3-thiazolidine hydrobromide 6 regioselectively, which was treated with isocyanates gave the corresponding 8 which is tautomer of 4. Antifungal screening (in vivo) of the synthesized compound 8 against typical plant diseases, which include rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, was carried out. Antifungal activities against rice blast of the compound 8 were weaker than those of 2-phenylimino-1,3-thiazoline 1. Some compounds showed weak antifungal activities against wheat leaf rust.

Excavation of 3-amino-2-benzylimino-1,3-thiazolines, Selective Fungicide against Phytophthora infestans and Magnaporthe grisea (토마토 역병균과 벼 도열병균에 선택적인 살균활성의 3-아미노-2-벤질이미노-1,3-티아졸린 유도체 발굴)

  • Hahn, Hoh-Gyu;Nam, Kee-Dal;Shin, Dong-Yoon;Choi, Gyung-Ja;Cho, Kwang-Yun
    • The Korean Journal of Pesticide Science
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    • v.10 no.3
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    • pp.165-171
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    • 2006
  • A new 3-amino-1,3-thiazoline chemical library was synthesized through parallel synthetic technology and in vivo antifungal activity of the compounds were investigated against the typical 6 plant diseases (100 ppm). The characteristic feature of these derivatives was that both a benzyl moiety in C-2 imino and an amino group in C-3 of 2-imino-1,3-thiazoline scaffold were substituted in the molecule respectively. Some compounds showed antifungal activity with selectivity against tomato late blight and rice blast. The fungitoxicity would be attributed to 3,4-dichlorophenyl moiety of the benzyl group.

Synthesis of New 2,4-Diimino-1,3-thiazoles and the Structure Determination (새로운 2,4-Diimino-1,3-thiazoles 유도체의 합성과 구조 결정)

  • Hoh-Gyu Hahn;Chul-soo Lim;Heduck Mah
    • Journal of the Korean Chemical Society
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    • v.47 no.1
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    • pp.38-42
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    • 2003
  • For the purpose of developing new agrochemical fungicides, compound 2 possessing 1,3-thiazole scaffold as well as urea moiety in the structure was designed through molecular modification of lead compound, 2-imino-1,3-thiazoline based on isosterism. The reaction of N-methylthiouea 5 and bromoacetonitrile in ethanol gave 2,4-diimino-1,3-thiazole 4 regioselectively, which was treated with phenyl isocyanates to give the corresponding 7 which is tautomer of 2. The structural assignment of 7 was confirmed by various spectra($^1H$ NMR, $^{13}C$ NMR, FT-IR, HRMS), and X-ray crystallographic data. Compound 8 which is a structural isomer of 7 was formed through thermodynamically unstable intermediate 2,4-diimino-1,3-thiazole 6.