• Journal of the Korean Chemical Society
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• v.40 no.2
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• pp.128-134
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• 1996

The kinetics of the hydrolysis of dihydro-1, 4-oxathiin derivatives were investigated by ultraviolet spectrophotometry in H2O at $25^{\circ}C.$ A rate equation which can be applied over a wide pH range was obtained. The substituent effects on the hydrolysis of dihydro-1, 4-oxathiin derivatives were studied and the rate of hydrolysis was shown to be accelerated by electron accepting groups. Final product of the hydrolysis was 2-(2-hydroxyethylthio)acetoacet-anilide enol form. On the basis of rate equations derived and judging from hydrolysis products obtained and from general base effect and substituent effects, plausible mechanism of the hydrolysis in various pH range have been proposed. Below pH 3.5, the hydrolysis was initiated by the protonation and followed by the addition of water to 2-carbon. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxide to 2-carbon. In the range of pH 4.0∼10.0, the addition of water to dihydro-1,4-oxathiin is rate controlling step.

• The Korean Journal of Pesticide Science
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• v.10 no.1
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• pp.1-6
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• 2006

A methodology for the syntheses of carboxanilides using solid support of 4-chloro-3-nitorbenzophenone oxime resin 5 was developed. Condensation of 4-chloro-3-nitorbenzophenone resin 6 with hydroxylamine hydrochloride salt gave oxime resin 5. The reaction of oxime resin 5 with dioxin and oxathiin derivatives 7a-d afforded the corresponding polymer-bound dioxin and oxathiin derivatives 9a-d. These polymer-bound resins 9a-d were treated respectively with aniline in the presence of acetic acid resulted in the corresponding dioxin carboxanilides 10a-d (yield, 5%-quantitative).

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1218-1220
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• 1999

• 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.

• Journal of the Korean Chemical Society
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• v.39 no.11
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• pp.878-880
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• 1995

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.759-761
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• 1991

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.185-190
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• 2005

Solid phase synthesis of 16, which is a derivative of the first systemic fungicide, carboxin 1 was described. Reaction of 1,3-oxathiolane derivative with solid resin of 4-hydroxy-3-nitrobenzophenone 6 gave 9 in 82% yield. Oxidation of sulfur in the solid 1,3-oxathiolane 9 by MCPBA followed by a ring expansion reaction under the acid catalyst afforded the corresponding dihydro-1,4-oxathiin derivative 12. Treatment of the solid 1,3-oxathiolane 9 with p-methoxyaniline resulted in 1,3-oxathiolane 14, 1,3-oxathiolane sulfoxide 15, dihydro-1,4-oxathiin 16, and acetoacetanilide derivative 17 in 41%, 35%, 14%, 10% yields, respectively.

• Archives of Pharmacal Research
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• v.23 no.4
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• pp.315-323
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• 2000

Syntheses of new analogues of oxathiin carboxanilide (UC84) and their antiviral activities were described. The heterocyclic carboxylic acids including oxathiins (4), thiazines (9) and dithiins (13) in which the methyl was replaced either by lipophilic trifluoromethyl- or bulky phenylgroup were synthesized starting from $\beta$-keto esters (5). Reaction of 4, 9 and 13 with thionyl chloride followed by treatment of the substituted aniline 22 gave the corresponding carboxanilides (24a~24f). The carboxanilides were subjected to Laweson's reagent the corresponding thiocarboxanilides (24g~24k). The antiviral activities of the synthesized compounds against human immunodeficiency virus type 1 (HIV-1), poliovirus type 1 (PV-1 ), coxsackie B virus type 3 (CoxB-3), vesicular stomatitis virus (VSV) and herpes simplex virus type 1 (HSV-1) were presented. The antiviral activity against HIV-1 of dithiin carboxanilide (24e) was similar with that of UC84 (24a). The corresponding thiocarboxanilides (24g~24k) showed higher inhibitory activity against HIV-1 than the carboxanilides (24a, 24b, 24d, 24e). The compounds in which ether the lipophilic trifluorormethyl substituents (24d, 24f, 24i ,24k) or bulky phenyl substituent is present in the heterocyclic compounds showed lower inhibitory activity than that of the methyl substituents is present in the compounds against the HIV-1. But the trifluoromethylated dithiin (24f) showed higher inhibitory activity against PV-1 and CoxB-3 virus than commercial antiviral agents, ribavirin (RV).

• 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.

• Journal of the Korean Chemical Society
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• v.33 no.2
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• pp.238-246
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• 1989

1,3-Oxathiolane sulfoxide 4 in which the sulfoxide oxygen and the 2-methyl group are on the same face of the oxathiolane ring undergoes a sigmatropic rearrangement to produce a ring expansion product. The structure of this product would be dihydro-1,4-oxathiin 6 or isomeric exo compound 7. This paper describes physical and chemical methods to determine the correct structure of the two alternatives. Thus, $^1HNMR$, UV spectroscopies, and mass spectrometry showed that the product actually obtained had the structure 6. It was also found that from deuteration reactions of the product the compound 7 was initaly formed and then tautomerized to endo compound 6.