• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.241-249
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• 2003

The reaction of 3-(1-ethoxycarbonyl)ethyl-1,2-dihydro-2-oxoquinoxaline (8) with hydrazine hydrate gave 3-(1-hydrazinocarbonyl)ethyl-2-hydroxyquinoxaline (9). The reaction of compound 9 with substituted benzaldehydes and heteroaryl aldehydes afforded 2-hydroxyquinoxalines (10-12), respectively. The reaction of compound 9 with alkyl (ethoxymethylene)cyanoacetates and ethoxymethylenemalononitrile resulted in the intramolecular cyclization to give the 5-amino-1-[2-(3-hydroxyquinoxalin-2-yl)propanoyl]-pyrazoles (13), respectively. Compounds 10-13 showed the tautomerism between the lactam and lactim forms in dimethyl sulfoxide solution. The tautomer ratios were determined by the $^1H$ NMR. The herbicidal and fungicidal activities of the synthesized compounds were investigated.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.385-393
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• 2004

2-Ethoxycarbonyl-3-methylquinoxaline 1,4-dioxide (8) was synthesized from benzofuroxan and ethyl acetoacetate. The reaction of compound 8 with hydrazine hydrate or selenium dioxide gave 2-hydrazinocarbonyl-3-methylquinoxaline 1,4-dioxide (9) or 2-ethoxycarbonyl-3-formylquinoxaline 1,4-dioxide (10), respectively. The reaction of compound 9 with alkanoyl chlorides, benzoyl chlorides, heteroacyl chlorides, and benzenesulfonyl chlorides afforded 3-methyl-2-(substituted hydrazinocarbonyl)quinoxaline 1,4-dioxides (11-14), respectively. The reaction of compound 9 with sodium azide gave 2-azidocarbonyl-3-methylquinoxaline 1,4-dioxide (15), and then its refluxing in dioxane/alcohols resulted in the Curtius rearrangement to give N-(3-methyl-1,4-dioxoquinoxalin-2-yl)-alkyl carbamates (16). The reaction of compound 15 with substituted anilines afforded 2-(3-substituted phenylureido)-3-methylquinoxaline 1,4-dioxides (17). The reaction of compound 10 with benzoic hydrazide or substituted anilines provided quinoxaline 1,4-di-oxides (18, 19), respectively. The herbicidal and fungicidal activities of the synthesized compounds were investigated.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.1-7
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• 2007

We have developed an efficient synthesis of 2(5H)-furanones using the microwave-promoted Suzuki-Miyaura coupling reaction and evaluated their fungicidal activities against six fungal pathogens in vivo. In addition, 2-cyclopentenones or 2-cyclohexenones possessing one or two additional methylene groups instead of the oxygen in the 2(5H)-furanone skeleton were also prepared by using the similar method. As the results of in vivo fungicidal screening against 6 plant diseases, a few derivatives displayed specific fungicidal activities against rice blast and tomato late blast. Further studies toward the optimization of the chemical structures are necessary for the development of novel fungicides with high potency.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3341-3347
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• 2010

A series of oxazolidinone-based strobilurin analogues were efficiently synthesized by the reaction of 3-(2-bromomethylphenyl) oxazolidin-2-one with 1-substituted phenyl-2H-pyrazolin-3-one. Their structures were confirmed and characterized by $^1H$-NMR, $^{13}C$-NMR, elemental analysis, and mass spectroscopy. In addition, the crystal structure of the target compound 3-(2-((1-phenyl-2H-pyrazol-3-yloxy)methyl)phenyl) oxazolidin-2-one was determined by single crystal X-ray diffraction. The bioassay results of these compounds indicated that some of the oxazolidin-2-one derivatives containing N-substituted phenyl 2H-pyrazol ring exhibited potential in vivo fungicidal activities against M. grisea at the dosage of $1\;g\;L^{-1}$.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.581-585
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• 1996

A new formal total synthesis of (+)-6-oxo-3, 4, 4a, 5-tetrahydro-3-hydroxy-2, 2-dimenthylnaphtho-1, 2-pyran (1) which has been known to have bactericidal, bacteriostatic, fungicidal, fungistatic activities against Staphylococcus aureus and other microorganism, is described. The key reaction involves enantioselective prenylation of .alpha.-tetralone via chiral lithioenamine.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.64-69
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• 1998

New thirty derivatives of 5,6-dihydro-2-trifluoromethyl-1,4-oxathiin carboxanilide as substrate(S) were synthesized and their fungicidal activities in vivo against rice sheath blight(Rhizoctonia solani) and wheat leaf rust(Puccinia recondita) were examined. The structure activity relationships(SAR) between the activities($pI_{50}$) and a physicochemical parameters of substituents(X) at the phenylcarbamoyl group were analyzed using the adaptive regression analysis method. The 3-methoxy, 11, 3-isopropyloxy, 13 and 3-isopropyl substituent, 25 as X on the phenylcarbamoyl group exhibited the most highest fungicidal activity against the two fungi. The fungicidal potency of the (S) against Puccinia recondita was higher than Rhizoctonia solani. In case of Rhizoctonia solani, the molecular hydrophobicity(${\pi}>0$) and resonance effect(R<0) by meta-alkyl substitutents with electron donating were important factors in determining fungicidal activity. And the HOMO energy(HOMO>0), ABSQ, sum of absolute values of the atomic charges on each atom and specific polarizability(Sp.Pol<0) of (S) were significantly influential towards fungicidal activity against Puccinia recondita.. The interaction between (S) and receptor agonist from the based on SAR studies proceeds through charge-control reaction, and conditions to show higher activity has been also discussed.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.36-40
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• 2001

A series of new 2-N-benzyl-5-phenoxy-3-isothiazolone derivatives were synthesized and their in vitro antifungal activities against resistant Phytophthora capsici (RPC) & sensitive Phytophthora capsici (SPC) with metalaxyl fungicide have been measured. In addition, influence of substituted 5-phenoxy group on the -antifungal activities ($pI_{50}$) and the reactivity of substrates were investigated. From the results, reactivity of none substituted substrate showed tendency displaying orbital-controlled reaction. The substituents on the 5-phenoxy ring showed selective fungicidal activity between SPC and RPC. Especially, the 4-fluoro substituent, 6 in the RPC and 4-nitro substituent, 3 in SPC exhibited strongly selective antifungal activity among them. The activities on the SPC would depend largely on the optimal molar refractivity ($MR_{(opt.)}=7.37cm^3/mol$) whereas the activities on the RPC would depend largely on the optimal highest occupied molecular orbital energy ($HOMO_{(opt.)}=-9.2137e.v.$) and weak electron donating (${\sigma}<0$) group. And Free-Wilson analyses revealed that the antifungal activity against RPC depends on the methoxy and bromo-substituent and all of the substituents contribute to antifungal activities against SPC.

• 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.

• The Korean Journal of Pesticide Science
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• v.7 no.2
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• pp.117-122
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• 2003

Modeling and synthesis of novel hydroxyethyl 2-iminothiazolines were carried out through molecular modification of lead compound, 2-phenyliminothiazolines 1, for the purpose of development of new fungicidal agrochemicals. Oxygen atom of the hydroxyethyl group in 2-iminothiazolines 3 would locate in the proximity of the imino carbon at C-2 of 2-iminothiazoline moiety through neighboring group participation, and so that it would affect the biological activity of the molecule. Reaction of $\gamma$-chloroacetoacetanilides 5 with hydroxyethylureas 6 gave 29 kinds of new corresponding hydroxyethyl 2-iminothiazolines 3 in high yields.

• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.149-152
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• 2006

Construction of focused library of 2-benzylimino-1,3-thiazolines 7 through molecular modification of 3-alkyl-2-phenylimino-1,3-thiazolines 1 which showed selective fungicidal activity against rice blast and their fungitoxic activity against 6 kinds of typical plant diseases was described. Fifty four compounds of focused library of 2-benzylimino-1,3-thiazolines 7 were synthesized from the reaction of the corresponding $\gamma$-chloroacetoacetanilides 6 with N-benzyl thioureas 5 by parallel synthetic methodology. As results of fungicidal screening against the typical plant diseases, twenty eight kinds of 7 at 100 ${\mu}g$ $mL^{-1}$ showed the control value over 50% against tomato late blight.