• Title, Summary, Keyword: ${\alpha},{\beta}$-unsaturated carboxanilide

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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.

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.

Construction of Dihydro-1,4-dioxins: Synthesis of Dihydro-1,4-dioxin-3-carboxanilides

  • Han, Ho Gyu;Jang, Gi Hyeok;Nam, Gi Dal
    • Bulletin of the Korean Chemical Society
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    • v.22 no.2
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    • pp.149-153
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    • 2001
  • A new methodology for construction of dihydro-1,4-dioxin skeleton was described. Introduction of thio group at the ${\alpha}-position$ of 8 followed by chlorination gave 11, which was to prevent an enolization as well as to promote the facile nucleophilic substitution reaction of ethylene glycol giving 16 in equilibrium with cyclic ether 19. Removal of thio group of 19 and dehydration in the presence of an acid catalyst gave dihydro-1,4-dioxin 21. In case of electron withdrawing trifluoromethyl group is subsituted in C-2, 18 was converted to the corresponding dihydro-1,4-dioxin 20 by the halogenation of hydroxy followed by treatment of triethylamine.

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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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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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