• Korean Journal of Weed Science
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• v.14 no.3
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• pp.184-191
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• 1994

A zearalenone derivative, methyldihydroxyzearalenone has been isolated from a plant pathogenic fungus, Drechslera portulacae which causes necrosis on the leaves and stem of Portulaca oleracea. It was characterized as 3, 4, 5, 6, 9, 10-hexahydro-8, 9, 16-trihydroxy-14-methoxy-3-methyl-1H-2-benzoxacyclotetradecine-1, 7(8H)-dione on the basis of spectral analysis. Methyldihydroxyzearalenone treatment at $3{\times}10^{-5}M$ inhibited root length of Echinochloa crus-galli and Abutilon avicennae by 35.7% and 72.6% as compared with the control, respectively.

• Korean Journal of Crystallography
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• v.13 no.2
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• pp.91-95
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• 2002

The structure of Cantharidin (Hexahydro-3a,7a-dimethy1-4,7-epoxyisobenzofuran-1,3-dione, C/sub 10/H/sub 12/O/sub 4/)has been determined by X-ray diffraction methods. The crystal system is orthorhombic, space group Pna2/sub 1/, unit cell constants, a＝11.0731(9) (equation omitted), b＝6.7344(4) (equation omitted), c＝12.5000(9) (equation omitted), α＝β＝γ＝90°, V＝932.13(12) (equation omitted), T=296K, Z＝4, D/sub c/＝1.398Mgm/sup -3/. The intensity data were collected on an Enraf-Nonius CAD-4 Diffractometer with graphite monochromated MoKα radiation(λ＝0.71073(equation omitted)). The molecular structure was solved by direct methods and refined by full-matrix least squares to a final R＝4.42% for 759 unique observed F/sub o/>4σ(F/sub o/) reflections and 140 parameters.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.21-22
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• 2002

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.163-164
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• 2004

• YAKHAK HOEJI
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• v.41 no.1
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• pp.7-13
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• 1997

A regiospecific total synthesis on the precursor(18b) of rhodomycinones is described. The anion of 3-carbomethoxy-1(3H)-isobenzofuranone(13) was respectively condensed wi th naphthalenone (12) and butenoate(8) derivatives which were, prepared by two different synthetic routes to afford 9-ethyl-6,7-dihydroxy 7,8,9,10-tetrahydronaphthacene-5,12 dione(18b) after oxidation and reduction.

• YAKHAK HOEJI
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• v.33 no.6
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• pp.377-379
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• 1989

The methylated compound of ellagic acid was isolated from Potentilla chinensis (Rosaceae). The isolated compound was 3, 3', 4-tri-O-methylellagic acid, [2, 3, 7-trimethoxy-8-hydroxy[1] benzopyrano-[5, 4, 3, cde][1] benzopyran-5, 10-dione], $C_{17}H_{12}O_8$, m.p. $293-295^{\circ}C$. The isolation of trimethylellagic acid was conducted by the column chromatography and the identification of the compound was carried out by the methods of IR, NMR and MS spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2918-2920
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• 2009

Various indan-1,3-dione derivatives were synthesized from the reaction of different phthalic anhydrides with diethylmalonate using montmorillonite KSF clay as a recyclable heterogeneous acidic catalyst and microwave irradiation in good yields and short reaction times.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.717-722
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• 1993

N-Phenyl oxadiazolidinedione derivatives II were synthesized and their herbicidal activities were measured against grass weeds. A parabolic relationship between molar refractivity (MR) of meta substituents of dione Ⅱ and their herbicidal activities was observed. With the substituents having MR value=${\sim}15$, the higher activities were obtained. Especially, the highest herbicidal activity (97% inhibition of weeds at 0.25 kg/ha) was observed by propyne IIr containing propargyloxy group as meta substituent.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.591-592
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• 1991

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1263-1307
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• 2002

Pseudo-first-order rate constants (kobs) have been determined for the nucleophilic substitution reactions of p-nitrophenyl diphenyl phosphinate (PNPDPP) with substituted phenoxides (XC6H4O - ) and butane-2,3-dione monoximate (Ox- ) in 0.1 M borate buffer (pH = 10.0) at 25.0 ${\pm}0.1^{\circ}C$. The kobs value increases sharply upon addition of cethyltrimethylammonium bromide (CTAB) to the reaction medium up to near 7 ${\times}$ 10-4 M CTAB and then decreases smoothly upon further addition of CTAB. The rate enhancement upon the addition of CTAB is most significant for the reaction with -O2CC6H4O- and least significant for the one with C6H5O- , indicating that the reactivity of these aryloxides in the presence of CTAB cannot be determined by the basicity alone. The strength of the interaction of these anionic aryloxides with the positively charged micellar aggregates has been suggested to be an important factor to determine the reactivity in the presence of CTAB. The kobs value for the reaction with Ox- increases also upon the addition of CTAB. However, the increase in the kobs value is much more significant for the reaction with Ox- than for the one with ClC6H4O- , indicating that Ox- is less strongly solvated than ClC6H4O- in H2O. The ${\alpha}-effect$ shown by Ox- in H2O has been attributed to the ground-state solvation difference between Ox- and ClC6H4O- .