• 약학회지
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• 제27권3호
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• pp.207-213
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• 1983

Chloramphenicol (CAF) was esterified with aspirin, naproxen and acetaminophen in order to develop new prodrugs which have double effect-antibiotic activity and antipyretic effect. Chloramphenicol acetylsalicylate (CAF-ASP), chloramphenicol naproxenate (CAF-NAX), and chloramphenicol acetaminophen succinate (CAF-SUC-ACET) were synthesized by using dicyclohoxylcarbodiimidc (D.C.C.) because of two hydroxyl group of chloramphenicol. Three synthetic prodrugs did not show bitterness and antibiotic activity in vitro, and were hydrolyzed in liver homogenate, but weren't in acid.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2436-2440
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• 2013

${\alpha}$-Muricholic acid was synthesized through 9 steps from chenodeoxycholic acid with 26% overall yield. Hyocholic acid was synthesized through 8 steps from the same starting material with 63% overall yield. Taurine conjugates of ${\alpha}$-muricholic acid and hyocholic acid were also prepared via their pentafluorophenyl ester.

• Bulletin of the Korean Chemical Society
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• 제5권3호
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• pp.97-100
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• 1984

Two novel malyngolide analogues, (${\pm}$)-dehydromalyngolide and (${\pm}$)-isomalyngolide, of (-)-malyngolide antibiotic have been synthesized by application of our previously developed synthetic sequence for the synthesis of (${\pm}$)-malyngolide. Dehydromalyngolide was synthesized from the known lactone (4) in a 55 % overall yield in six steps, while isomalyngolide was synthesized from the readily available keto ester (11) in a 56 % overall yield in four steps.

• Bulletin of the Korean Chemical Society
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• 제20권7호
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• pp.801-804
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• 1999

Thermal and photoinduced silylallylation reactions of organic halides with 3-stannyl-2-(silylmethyl)propene are explored. Silylallylations occur in moderate to high yields, producing various functionalized allylsilane products in which halide carbon is bonded to the terminal alkenic carbon of allylsilane with the removal of tributyltin group. The reactions, which tolerate functional groups such as carbonyl, ester, nitrile, acetal, and ketal, hold synthetic potential for the construction of functionalized allylsilanes.

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.335-339
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• 1998

Syntheses of carbapenam skeletons were achieved from 3-benzyloxypropanal through 1,3-dipolar cycloaddition. 3-Benzyloxypropanal was reacted with N-hydroxyglycine ester to give C-(2-benzyloxyethyl)-N-alkoxycarbonylmethylnitrone (6). 1,3-Dipolar cycloaddition of the nitrone with ethyl crotonate gave 3-(2-benzyloxyethyl)isoxazolidine (7). Compound 7 was transformed to 4-(2-hydroxyethyl)-2-azetidinone (11). Compound 11 was converted to 4-(2-iodoethyl)-2-azetidinone (13) or 4-phenylthiocarbonylmethyl-2-azetidinone (16) which was cyclized to give 6-(1-hydroxyethyl)carbapenam-3-carboxylate (14, 17).

• 한국환경농학회지
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• 제11권2호
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• pp.116-124
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• 1992

합성 pyrethroid계 살충제의 화학구조중 alcohol부분이 2-methyl biphenyl 그룹이 있는 bifenthrin과 ${\alpha}$-cyanobenzyl ester 그룹이 있는 cyhalothrin의 분해양상을 비교하기 위하여 토양의 환경조건을 호기적, 혐기적 및 살균조건으로 하였을 때와 pH를 변화시킨 수용액중에서 분해양상을 조사한 결과는 다음과 같다. Bifenthrin의 호기적 토양조건에서의 분해반감기는 칠곡 및 복현 토양에서 85.1 및 61.2일이었으며 cyhalothrin은 각각 54.6 및 32.2일로서 유기물함량이 많은 복현토양에서 두 약제 모두 분해가 빨랐다. 두 약제 모두 혐기적 조건 및 살균 조건의 토양에서는 매우 느린 분해양상을 보였다 Bifenthrin과 cyhalothrin의 분해는 주로 호기성 미생물이관여하는 것으로 나타났다. 두 약제간에는 cyhalothrin이 bifenthrin보다 분해반감기가 30일 정도 빨랐다. 수용액의 pH가 10인 알카리성 조건에서 cyhalothrin이 bifenthrin보다 상당히 빨리 분해되 었으며 pH 2 및 6의 산성조건에서도 두 약제 모두 분해가 지연되었다.

• 접착 및 계면
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• 제19권1호
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• pp.5-12
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• 2018

본 연구는 선처리제 공정을 생략하고 우수한 접착 특성을 가지는 합성피혁용 스킨(skin) 수지제조에 관한 것으로 이성분계 혼합 폴리우레탄 수분산체를 제조하여 이에 대한 선처리제(primer)를 생략한 접착 시편의 접착특성을 평가하는 것이다. 이성분계 혼합 폴리우레탄 수분산체의 제조는 에스터(ester)계 폴리우레탄 수지(PU-T)와 카보네이트(carbonate)계 폴리우레탄 수지(PU-C)를 각각 합성하고 이를 배합함으로써 최종 수지를 얻었다. 선처리제를 생략한 접착시편의 접착강도 측정결과, 우수한 상태접착강도 (Ethylene vinyl acetate(중창): $4.2kg_f/cm$, 고무(겉창) : $4.4kg_f/cm$)를 가짐을 확인할 수 있었다. 이는 신발 제조 공정에서 필수불가결하게 사용되었던 선처리제(primer) 공정을 생략가능하게 함으로써 공정의 단축과 선처리제(primer)에서 발생되는 휘발성유기화합물 (VOCs)의 감소를 가져와 친환경적인 장점을 지닌다.

• 대한화학회지
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• 제40권11호
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• pp.692-698
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• 1996

해양천연물 Discokiolide B의 옥사졸 골격인 discokiic acid 1을 합성하였다. 2[2'-(4-Phenyl-3-butenyl)]-1, 3-oxazole-4-carboxaldehyde(4a)와 methyl propionate의 리튬 enolate와의 알돌반응으로부터 discokiic acid methyl ester를 합성하였다. 중요한 반응중간체인 2[2'-(4-Phenyl-3-butenyl)]-1, 3-oxazole-4-carboxaldehyde(4a)는 디아조 말론알데히드와 니트릴을 로듐촉매하에서 반응시켜 얻었다. Discokiic acid의 오른쪽 측쇄 부분인 3-hydroxy-2-methyl 프로판산 부분의 상대적인 입체화학을$^1H$와 $^{13}C$ 핵자기공명 데이터에 근거하여 결정하였다.

• 한국기계가공학회지
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• 제2권1호
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• pp.5-14
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• 2003

Cutting fluids used for superfinishing are usually mineral based oils With sulfur and chlorine additives. These cutting fluids are an environmental hazard and can adversely affect the health of personnel on the shop floor. The present investigation was undertaken to explore the possible alternative use of environmentally-conscious cutting fluids for superfinishing. Unlike mineral oils, these environmentally-conscious cutting fluids are biodegradable and non-hazardous. Experiments were conducted for testing an ester oil manufactured by Accu-Lube applied in miniscule amounts using the Minimum Quantity Lubrication (MQL) technique. A significant improvement in stock removal was found with the 6 stones tested. The specific energy values associated with the process were also significantly lower than those obtained previously with conventional straight oils and the water based synthetic fluid, indicative of better lubrication, while the surface roughness was comparable. These tests prove that MQL with ester oils can be a very effective environmentally-conscious alternative to conventional straight oils.

• 약학회지
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• 제38권4호
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• pp.455-461
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• 1994

Each nitrogen and oxygen site isotope enriched the cyclophosphamide metabolite phosphoramide mustard was synthesized. Reaction of N,N-bis(2-chloroethyl)phosphoramidic dichloride$[Cl_2P(O)N(CH_2CH_2Cl)_2]$ with benzyl alcohol and ammonia gave N,N-bis(2-chloroethyl)phosphorodiamidic acid phenylmethyl ester $[BzO(H_2N)P(O)N(CH_2CH_2Cl)_2]$. Catalytic hydrogenation of this benzyl ester followed by the addition of cyclohexylamine provided PM. Incorporation of $^{15}NH_3$ into this general scheme gave PM with a $^{15}NH_2$ moiety. Glycine-$^{15}N$ was converted to bis(2-chloroethyl)amine-$^{15}N$ hydrochloride which, in turn, provided for N,N-bis(2-chloroethyl)phosphorodiamidic-$^{15}N$ dichloride. Use of this compound in the general synthetic pathway yielded PM CHA with $^{15}N$ in the mustard moiety. $^{17}O$-Enriched PM was generated through the use of benzyl alcohol-$^{17}O$. To obtain the alcohol, labelled benzaldehyde was made by exchange with $^{17}OH_2$ and was then reduced with sodium borohydride.