• Title, Summary, Keyword: development of new agrochemical

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Field Performance of a New Fungicide Ethaboxam Against Cucumber Downy Mildew, Potato Late Blight and Pepper Phytophthora Blight in Korea

  • Kim, Dal-Soo;Prak, Hyun-Cheol;Chun, Sam-Jae;Yu, Seung-Hun;Park, Kyong-Ju;Oh, Jeung-Haing;Shin, Kwang-Hoon;Koh, Young-Jin;Kim, Byung-Sup;Hahm, Young-Il;Chung, Bong-Koo
    • The Plant Pathology Journal
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    • v.15 no.1
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    • pp.48-52
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    • 1999
  • Ethaboxam is the first proprietary fungicide developed in Korea, registered in 1998 and commercialized in 1999 by LG Chemical Ltd., Korea. It is a derivative of aminothiazole carboxamide and formulated into 25% wettable powder for practical application in fields. Ethaboxam effectively controlled cucumber downy mildew caused by Pseudoperonospora cubensis, potato late blight caused by Phytophthora infestans, and pepper Phytophthora blight caused by P. capsici, and was superior or comparable to the commercial standards, when foliarly sprayed 3∼5 times until dripping off at approximately 7-day intervals during the growing season. Ethaboxam was required at least 125 mg/liter and 250 mg/liter for effective control of cucumber downy mildew, and potato late blight and pepper Phytophthora blight, respectively. There was not phytotoxicity observed o leaves, stems or fruits of cucumber, potato and pepper from any trial.

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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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Syntheses of Pyrrolo[2,1-b]thiazole Carboxanilides and Their Selective Antifungal Activities against Rice Blast and Wheat Leaf Rust (Pyrrolo[2,1-b]thiazole 카르복스아닐라이드 유도체의 합성 및 그들의 벼 도열병균과 밀 붉은녹병균에 대한 선택적인 항균활성)

  • Hahn, Hoh-Gyu;Nam, Kee-Dal;Yang, Bum-Seung;Choe, Gyeong-Ja;Cho, Kwang-Yun;Lee, Seon-Woo
    • The Korean Journal of Pesticide Science
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    • v.9 no.2
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    • pp.122-131
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    • 2005
  • For development of new agrochemical fungicide, syntheses of pyrrolo[2,1-b]thiazole carboxanilide derivatives 9 and antifungal screening against 6 kinds of plant pathogens were carried out. Functionalization of carboxylic acid on C-2 into carboxanilide in the pyrrolo[2,1-b]thiazole resulted in new 20 candidates, in which are ${\alpha},{\beta}$-unsaturated carboxanilide and methyl groups that are in cis relationship. Treatment of acetoxy-1,4-thiazin with magnesium in refluxing methanol gave pyrrolo[2,1-b]thiazole ethyl ester 4 in higher yield than that of the previous report. Hydrolysis of this compound afforded the corresponding acid 5, which reacted with aniline derivatives in the presence of coupling reagent, DIC to give pyrrolo[2,1-b]thiazole carboxanilides 9. As the result of in vivo antifungal assay of 9 against rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, some compounds showed selectively antifungal activities against the rice blast and wheat leaf rust.

A Synthesis of 1,4-Thiazine Carboxanilide: Neighboring Group Participation in Pummerer Reaction (1,4-Thiazine Carboxanilide의 합성: Pummerer 반응에서의 인접기 참여효과)

  • Han, Ho-Gyu;Nam, Gi-Dal;Ma, Hye-Deok
    • Journal of the Korean Chemical Society
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    • v.46 no.4
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    • pp.330-336
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    • 2002
  • For the purpose of development of new agrochemical fungicide of ${\alpha},{\beta}-unsaturated$ carboxanilide series a synthesis of 4-acetyl-3-methyl-N-phenyl-1,4-thiazine-2-carboxamide (6) is described. Pummerer reaction of sulfoxide 7 obtained by sulfoxidation of dihydro-1,4-thiazine methyl ester 11 gave ${\alpha}-acetoxy$ dihydro-1,4-thiazine 10a. Under the same reaction conditions, dihydro-1,4-thiazine carboxanilide sulfoxide 14 was converted to acetoxymethyl dihydro-1,4-thiazine 18 through vinylogous Pummerer reaction involving carboxanilide of sulfonium ion through intermediate 15.1,4-Thiazine carboxanilide 6 was synthesized from the treatment of ${\alpha}-acetoxy$ dihydro-1,4-thiazine 10a with acid cat-alyst followed by hydrolysis and then the reaction with aniline.

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 Benzylimino-1,3-oxathioles and Their Fungicidal Activity (새로운 2-Benzoylimino-1,3-oxathiole 유도체의 합성 및 살균활성)

  • Nam, Kee-Dal;Shin, Sun-Ho;Mah, He-Duck;Lee, Seon-Woo;Cho, Kwang-Yun;Hahn, Hoh-Gyu
    • Applied Biological Chemistry
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    • v.45 no.3
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    • pp.157-161
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    • 2002
  • New 2-benzoylimino-1,3-oxathile derivatives 3 were synthesized and tested their fungicidal activities for the development of new agrochemical fungicide. Reaction of ${\gamma}-chloro-{\beta}-keto$ anilide derivative 5 with potassium thiocyanate followed by the treatment of acid catalyst gave cyclyzed 2-imino-1,3-oxathiole 3. New compound 3 reacted with benzoyl· chlorides to afford the corresponding 2-benzoylimino-1,3-oxathiole derivatives 7. Antifungal screening (in vivo) of the synthesized compounds 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. No significant fungicidal activities were shown of the synthesized compounds at 100 mg/l.

Application of Lipinski Rule for 3-amino-2-phenylimino-1,3-thiazolines and Their Syntheses (3-아미노-2-페닐이미노-1,3-티아졸린 유도체에 대한 Lipinski 법칙의 적용 및 그들의 합성)

  • Park, Ik-Kyu;Hahn, Hoh-Gyu
    • The Korean Journal of Pesticide Science
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    • v.10 no.2
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    • pp.69-75
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    • 2006
  • For the development of new agrochemical fungicide 3-amino-2-phenylimino-1,3-thiazolines 2 were designed through the molecular modification based on isostere concept of 3-methyl-2-phenylimino-1,3-thiazolines 1 which showed antifungal activity against rice blast. All the compounds 2 were fit Lipinski rule and they had higher solubility in water than that of 1 by virtual calculation. We constructed 195 kinds of focused library of 3-amino-2-phenylimino-1,3-thiazolines through 6H-[1,3,4]thiadiazines (195 compounds) which synthesized from the reaction of thiourea 4 with $\gamma$-chloroacetoacetanilides 5.

Synthesis of trifluoromethylated dihydro-1,4-dithiin carboxamides and their antifungal activities (Trifluoromethylated Dihydro-1,4-dithiin carboxanilide 유도체의 합성 및 살균활성)

  • Hahn, Hoh-Gyu;Nam, Kee-Dal;Chang, Kee-Hyuk;Lee, Seon-Woo;Cho, Kwang-Yun
    • The Korean Journal of Pesticide Science
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    • v.5 no.2
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    • pp.26-32
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    • 2001
  • [ ${\alpha},{\beta}$ ]-Unsaturated carboxamides 12 with trifluromethylated dihydro-1,4-dithiins were synthesized for the purpose of development of new agrochemical fungicide. Chlorination of trifluoromethylated ${\beta}$-ketoester 4 followed by tile reaction with 1,2-ethanedithiol gave intermediate 1,4-dithiane 9. Without purification of 9 substitution of hydroxy by chlorine followed by dehydrochlorination in the presence of triethylamine afforded trifluoromethylated dihydro-1,4-dithiin ethyl ester 7. Activation of the hydroxy of the carboxylic acid 10 obtained from the hydrolysis of 7 and then reacted with various amines gave the corresponding trifluoromethylated dihydro-1,4-dithiin carboxamides. Antifungal screening (in vivo) against typical plant diseases, Rice Blast, Rice Sheath Blight, Cucumber Gray Mold, Tomato Late Blight, Wheat Leaf Rust, and Barley Powdery Mildew of the synthesized compounds was carried out. As a result, most of the compounds shlowed weak antifungal activities and some compounds in which isopropyl group was substituted in meta of the phenyl showed antifungal activity (99%) at 250 ppm against the disease Wheat Leaf Rust.

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Synthesis of Trifluoromethylated Dihydro-1,4-oxathiin Carboxanilides and Their Fungicidal Activity (삼불화메틸기가 포함된 디히드로-1,4-옥사티인 카르복스아닐리드 유도체의 합성과 살균 활성)

  • Nam, Kee-Dal;Kim, Jin-Cheol;Cho, Kwang-Yun;Hahn, Hoh-Gyu
    • Applied Biological Chemistry
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    • v.44 no.3
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    • pp.191-196
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    • 2001
  • ${\alpha},{\beta}$-Unsaturated carboxanilides 5 with trifluromethylated dihydro-1,4-oxathiins were synthesized for the development of new agrochemical fungicide. Chlorination of trifluoromethylated ${\beta}-keto$ ester 6 followed by the reaction with 1,2-mercaptoethanol gave intermediate 1,4-oxathiane 11. Without purification of 11, substitution of hydroxy group by chlorine, followed by dehydrochlorination of 10 in the presence of triethylamine afforded trifluoromethylated dihydro-1,4-oxathiin ethyl ester 9. Acylation of the hydroxy group of the carboxylic acid 12 followed by treatment of various amines gave the corresponding trifluoromethylated dihydro-1,4-oxathiin carboxamides 5. Antifungal screening (in vivo) of the synthesized compounds 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. Where meta position of the phenyl group was substituted with isopropoxy or isopropyl group, excellent antifungal activities against rice sheath blight and wheat leaf rust were detected.

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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.