• Carbon letters
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• 제16권4호
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• pp.270-274
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• 2015

• 한국산업융합학회 논문집
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• 제6권2호
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• pp.123-129
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• 2003

Oxindoles(6a-g) are obtained by rhodium(II)-catalyzed Wolff rearrangement of diazoquinolinediones in moderate yields. Treatment of 6a-g oxindole derivatives reacted with CAN in acetonitrile at room temperature to gave 7a-g isatins in good yields. The structures of these compound were identified by MP, IR and NMR-spectra.

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.31-35
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• 1991

Three isomers of damascenone, odorous terpenic ketones, have been synthesized conveniently from a same starting material, ethyl 2,6,6-trimethyl-4-oxo-2-cyclohexene-1-carboxylate(1), which was easily available by the acid-catalyzed condensation of mesityl oxide or acetone with ethyl acetoacetate. ${\alpha}$-Damascenone(7) was prepared by converting the enone ester 1 into the corresponding tosylhydrazone(4), followed by treating with 4 molar equiv of allyllithium. ${\beta}$-Damascenone(12) was synthesized by chemoselective reduction of 1 with sodium borohydride/cerium chloride to give corresponding allylic alcohol 8, conversion of 8 into acetate 9, and thermal decomposition of 9 with DBU to afford ethyl ${\beta}$-safranate(10), followed by reaction with an excess amount of allyllithium. ${\gamma}$-Damascenone(15) was obtained by dehydration of 8 with boric acid to furnish ${\gamma}$-safranate(13), followed by treatment with 2 molar equiv of allyllithium.

• 분석과학
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• 제6권5호
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• pp.435-442
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• 1993

루빈산이 결합된 카르복시메틸화된 폴리아민-폴리우레아(RCCPPI) 수지가 클로로카르복시메틸화된 폴리아민-폴리우레아(CCPPI) 수지와 루빈산으로부터 1단계 반응에 의하여 합성되었다. 이 수지의 구조는 적외선 분광광도법, 원소분석 및 시차열분석법으로 확인되었다. 이 수지에 대한 중금속 흡착특성은 용액의 pH를 변화시키면서 뱃치법에 의하여 분포계수($K_d$)를 측정하고, 프론탈크로마토그래피법으로 관류점을 측정하여 조사하였다. 중금속 이온용액을 이 수지로 충진된 관에 통과시킴에 의하여 고농도의 나트륨, 칼슘 및 아세트산염 용액 중에 존재하는 미량 중금속 이온을 최적 pH에서 농축 및 회수 정량할 수 있었다. 농축 인자는 25 이상이었고 흡착된 중금속들은 0.025M EDTA 용액(pH 9.0)으로 회수 정량하였다.

• Bulletin of the Korean Chemical Society
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• 제19권6호
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• pp.671-676
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• 1998

The formation and dissociation rates of $Ce^{3+}$ Complexes of the 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-NN', N",N"'-tetraacetic acid (1), 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-N,N',N",N"'-tetramethylacetic acid (2), and 1,4,7,10-tetraaza-13,16-dioxacyclooctadecane-N,N',N",N"'-tetrapropionic acid (3) have been measured by the use of stopped-flow spectrophotometry. Observations were made at 25.0±0.1 ℃ and at an ionic strength of 0.10 M $NaClO_4$. The complexation of $Ce^{3+}$ ion with 1 and 2 proceeds through the formation of an intermediate complex $(CeH_3L^{2+})^*$ in which the $Ce^{3+}$ ion is incompletely coordinated. This may then lead to be a final product in the rate-determining step. Between pH 4.76 and 5.76, the diprotonated $(H_2L^{2-})$ from is revealed to be a kinetically active species despite of its low concentration. The stability constants $(logK(CeH_3L^{2+}))$ and specific water-assisted rate constants $(k_{OH})$ of intermediate complexes have been determined from the kinetic data. The dissociation reactions of $Ce^{3+}$ complexes of 1, 2, and 3 were investigated with $Cu^{2+}$, ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid-catalyzed contributions. The effect of buffer and $Cu^{2+}$ concentration on the dissociation rate has also been investigated. The ligand effect on the dissociation rate of $Ce^{3+}$ complexes is discussed in terms of the side-pendant arms and the chelate ring sizes of the ligands.