• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.890-895
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• 1997

The approximate rates and stoichiometry of the reaction of excess lithium tripiperidinoaluminum hydride (LTPDA), an alicyclic aminoaluminum hydride, with selected organic compounds containing representative functional groups under the standardized conditions (tetrahydrofuran, 25°) were examined in order to define the reducing characteristics of the reagent for selective reductions. The reducing ability of LTPDA was also compared with those of the parent lithium aluminum hydride (LAH) and lithium tris(diethylamino)aluminum hydride (LTDEA), a representative aliphatic aminoaluminum hydride. In general, the reactivity of LTPDA toward organic functionalities is weaker than LTDEA and much weaker than LAH. LTPDA shows a unique reducing characteristics. Thus, benzyl alcohol, phenol and thiols evolve a quantitative amount of hydrogen rapidly. The rate of hydrogen evolution of primary, secondary and tertiary alcohols is distinctive. LTPDA reduces aldehydes, ketones, esters, acid chlorides and epoxides readily to the corresponding alcohols. Quinones, such as p-benzoquinone and anthraquinone, are reduced to the corresponding diols without hydrogen evolution. Tertiary amides and nitriles are also reduced readily to the corresponding amines. The reagent reduces nitro compounds and azobenzene to the amine stages. Disulfides are reduced to thiols, and sulfoxides and sulfones are converted to sulfides. Additionally, the reagent appears to be a good partial reducing agent to convert primary carboxamides into the corresponding aldehydes.

• 한국식품영양학회지
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• 제12권2호
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• pp.142-149
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• 1999

Moisture absorption rate of rice according to the soaking time was higher at $25^{\circ}C$ than 4$^{\circ}C$ and the op-timum soaking time was 1hr at $25^{\circ}C$. When the ratios of added water for rice cooking were 1.3 in an elec-tric cooker and pressure cooker and 1.7 in an Dookbaeki sensory an mechanically evaluation of cooked rice were highly evaluated. The total number of peak on gas chromatography profile were 89 in an press-ure cooker 56 in an electric cooker and 83 in an Dookbaeki and major volatile compounds of cooked rice were aliphatic hydrocarbons cyclic hydrocarbons aromatic hydrocarbons aldehydes alcohols ketones and thiourea. Furan that is in sweety was not detected in volatile components of cooked rice of electric cooker.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3640-3644
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• 2012

An efficient synthetic method for direct Henry reaction catalyzed by a biguanide; namely metformin, as an organosuper-base, between a variety of aromatic and aliphatic aldehydes and nitromethane under neat conditions has been developed. Convenient procedure for removal of the catalyst, chemoselective acquiring of ${\beta}$-nitroalcohols as predominant products, as far as possible short reaction time with excellent conversions are advantages of the developed protocol.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3738-3742
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• 2011

Bismuth tribromide ($BiBr_3$) catalyzed Mannich-type reactions of N-acyliminium ions which generated in situ from N-benzyloxycarbonylamino p-tolylsulfones have been developed. In the presence of catalytic amount of $BiBr_3$, N-benzyloxycarbonylamino p-tolylsulfones prepared from aromatic and aliphatic aldehydes reacted with silyl enol ether and silyl enol ester under mild reaction conditions to afford N-Cbz-protected ${\beta}$-amino ketones and N-Cbz-protected ${\beta}$-amino esters in moderate to good yield, respectively.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2887-2889
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• 2009

An efficient and easy method for one-pot three-component synthesis of amidoalkyl naphthols by the condensation of aromatic/heteroaromatic/aliphatic aldehydes, 2-naphthol and amides or urea under thermal condition at $60^{\circ}C$ in the presence of acidic ionic liquid 1-butyl-3-methylimidazolium hydrogen sulphate ([bmim]$HSO_4$) has been described.

• 한국식품영양과학회지
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• 제16권2호
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• pp.136-146
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• 1987

도라지 뿌리의 향기성분을 규명하고자 도라지 뿌리의 향기성분을 상압 수증기 증류법으로 포집하여 중성, 염기성, 약산성 및 산성성분으로 분획하였다. Diazomethane 법으로 methyl ester 화한 산성부분을 위시한 4부분은 모세관 column을 장치한 GC 및 GC-MS로 분석하였으며 함황화합물은 FPD 검출기로써 검출하였다. 도라지 뿌리로부터 aliphatic hydrocarbons류 6종, aromatic hydrocarbons류 10종, terpene hydrocarbons류 2종 alcohol류 12종, terpene alcohol류 8종 aldehyde류 17종 terpene aldehyde류 3종 ketone류 5종 ester류 5종, furan류 3종, thiazole류 2종, lactone류 2종, sulfide류 2종, phenol류 2종, 산류 12종 및 기타 5종을 위시하여 총 103종의 향기성분이 동정되었다. Caboxylic acid를 제외한 향기성분은 대부분 중성부분에서 동정되었고, 관능검사의 결과에서도 중성부분이 도라지 뿌리의 향기를 재현하는데 필요불가결한 것으로 나타났다. 관능검사의 결과, 중성부분에서 동정된 1-hexanal, trans-2-hexenal, 1-hexanol, cis-3-hexenol, trans-2-hexenol, 1-octenen-3-ol 등은 도라지 뿌리의 풋냄새의 주성분인 것으로 생각된다.

• 한국조리학회지
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• 제19권3호
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• pp.105-115
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• 2013

본 연구는 크릴육으로 크릴반응향을 만들어 휘발성 향기 성분을 살펴보고 이를 데리야끼소스에 적용하여 데리야끼소스의 기초자료를 마련하기 위한 연구이다. 따라서 본 연구를 위해 먼저, 반응향 제조에 크릴육을 이용하였고 이의 가수분해물을 이용해 Grilled-type과 Boiled-type으로 나누어 실험하였다. 또한, 반응향의 휘발성 향기성분을 알아보기 위하여 반응액 20 mL로 휘발성 성분을 포집하고 이것을 GC-MSD로 분리 동정하였다. 제조되어진 3가지 데리야끼소스를 10가지 항목인 삶은 야채향, 삶은 감자향, 삶은 새우향, 구운 새우향, 비린 향, 톡쏘는 향, 탄 향, 달콤한 향, 화학취, 진흙냄새와 좋아하는 정도에 대한 순서를 살펴보았으며 그 연구 결과는 다음과 같다. 크릴육의 Grilled-type에는 35개, Boiled-type에서는 33개의 휘발성 성분이 분리 동정되었다. Grilled-type에서는 황함유화합물, aliphatic compounds, alcohol류, ketone류, pyrazine류, other aromatic compounds의 순으로 휘발성 성분이 많았고, Boiled-type에서는 aldehydes, furans, other nitrogen- containing compounds의 순으로 휘발성 성분이 많았다. 데리야끼소스의 관능검사 결과는 boiled shrimp, roasted shrimp, sweet한 항목에서 유의적인 차이가 나타났다. 이상의 결과로 크릴을 이용하여 크릴반응향을 만들어 이를 적용한 데리야끼소스의 제조 가능성이 있는 것으로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제15권2호
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• pp.132-138
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• 1994

Bis(diethylamino)aluminum hydride was utilized in a systematic study of the approximate rates and stoichiometry of the reaction of excess reagent with 55 selected organic compounds containing representative functional groups under standardized conditions (THF, $0^{\circ}C$, reagent to compound=4 : 1) in order to define the characteristics of the reagent for selective reductions. The reducing action of BEAH was also compared with that of the parent aluminum hydride. The reducing action of the reagent is quite similar to that of aluminum hydride, but the reducing power is much weaker. Aldehydes and ketones were readily reduced in 1-3 h to the corresponding alcohols. However, unexpectedly, a ready involvement of the double bond in cinnamaldehyde was realized to afford hydrocinnamyl alcohol. The introduction of diethylamino group to the parent aluminum hydride appears not to be appreciably influential in stereoselectivity on the reduction of cyclic ketones. Both p-benzoquinone and anthraquinone utilized 2 equiv of hydride readily without evolution of hydrogen, proceeded cleanly to the 1,4-reduction products. Carboxylic acids and acid chlorides underwent reduction to alcohols slowly, whereas cyclic anhydrides utilized only 2 equiv of hydride slowly to the corresponding hydroxylacids. Especially, benzoic acid with a limiting amount of hydride was reduced to benzaldehyde in a yield of 80%. Esters and lactones were also readily reduced to alcohols. Epoxides examined all reacted slowly to give the ring-opened products. Primary and tertiary amides utilized 1 equiv of hydride fast and further hydride utilization was quite slow. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Among them, benzamide and N,N-dimethylbenzamide gave ca, 90% yields of benzaldehyde. Both the nitriles examined were also slowly reduced to the amines. Unexpectedly, both aliphatic and aromatic nitro compounds proved to be relatively reactive to the reagent. On the other hand, azo- and azoxybenzenes were quite inert to BEAH. Cyclohexanone oxime liberated 1 equiv of hydrogen and utilized 1 equiv of hydride for reduction, corresponding to N-hydroxycyclohexylamine. Pyridine ring compounds were also slowly attacked. Disulfides were readily reduced with hydrogen evolution to the thiols, and dimethyl sulfoxide and diphenyl sulfone were also rapidly reduced to the sulfides.

• Preventive Nutrition and Food Science
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• 제6권2호
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• pp.87-90
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• 2001

The volatile flavor components of snow crabs from the Young-duk coast of Korea and their concentrated cooker effluent were isolated by a modified method from Likens and Nickerson, using a simultaneous distillation and extraction apparatus. The concentrated extract was analyzed and identified by gas chromatography and GC-MS. The flavor profile of boiled crab demonstrated that the favorable flavor characteristic of crab involved a seafood-like note, and that of concentrated cooker effluent demonstrated that the weak boiled crab flavor involved a fishy note. The main flavor components of boiled crab were heterocyclic compounds including alkylpyrazines, thizoles and thiolanes, aliphatic ketones including 2-heptanone and nonanone. On the other hand, the main flavor components of cooker effluent were aldehydes including 3-methylbutanal, alipatic ketones including 2-heptanone and alkanes including 2,6,10,14-tetramethyl-pentadecane. Almost all of heterocyclic compounds, which seem to be important contributors to the flavor of boiled crab, were not identified in concentrated cooker effluent. As a result, there may be a need to add the crab flavor components formed through model experiments of Maillard reactions to the concentrated cooker effluent for human consumption.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.218-224
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• 2013

The aldo-keto reductases catalyze reduction reactions using various aliphatic and aromatic aldehydes/ketones. Most reductases require NADPH exclusively as their cofactors. However, NADPH is much more expensive and unstable than NADH. In this study, we attempted to change the five amino acid residues that interact with the 2'-phosphate group of the adenosine ribose of NADPH. These residues were selected based on a docking model of the YOL151W reductase and were substituted with other amino acids to develop NADH-utilizing enzymes. Ten mutants were constructed by site-directed mutagenesis and expressed in Escherichia coli. Among them, four mutants showed higher reductase activities than wild-type when using the NADH cofactor. Analysis of the kinetic parameters for the wild type and mutants indicated that the $k_{cat}/K_{m}$ value of the Asn9Glu mutant toward NADH increased 3-fold. A docking model was used to show that the carboxyl group of Glu 9 of the mutant formed an additional hydrogen bond with the 2'-hydroxyl group of adenosine ribose. The Asn9Glu mutant was able to produce (R)-ethyl-4-chloro-3-hydroxyl butanoate rapidly when using the NADH regeneration system.