• Bulletin of the Korean Chemical Society
• /
• 제30권11호
• /
• pp.2555-2558
• /
• 2009

The condensation of cyclic ketone with aromatic aldehydes in the presence of ammonium acetate under ethanol media affords the corresponding 5-aryl-7,8,13,14-tetrahydrodibenzo[a,i]phenanthridine with excellent yield. This mild and efficient procedure with high yield is also applied to the synthesis of 2,4-diaryl-6,7-benzo-3-azabicyclo- [3.3.1]nonan-9-ones and ${\alpha},{\alpha}{$’-bis(substituted benzylidene)cycloalkanones.

• Bulletin of the Korean Chemical Society
• /
• 제12권1호
• /
• pp.26-31
• /
• 1991

Facile and efficient syntheses of terpenic perfumeries cis-jasmone, dihydrojasmone, and tetrahydrojasmone have been investigated. Cis-jasmone was synthesized by successive metallation followed by alkylation of acetone N,N-dimethylhydrazone with (Z)-2-penten-1-yl tosylate (or 2-pentyn-1-yl tosylate) and propylene oxide in one flask to give a ketonic alcohol, which was oxidized to the corresponding diketone, followed by base-catalyzed intramolecular aldol condensation to give a regioselective cyclization product. Dihydrojasmone and tetrahydrojasmone could be conveniently obtained from 2-octanone. The dimethylhydrazone of the ketone was lithiated with butyllithium and reacted with propylene oxide to give a ketonic alcohol, which was oxidized to a diketone, followed by base-catalyzed intramolecular cyclization to afford dihydrojasmone. Tetrahydrojasmone was prepared by converting the ketonic alcohol into corresponding iodoketone, followed by base-catalyzed intramolecular cycloalkylation to furnish an odoriferous product.

• Bulletin of the Korean Chemical Society
• /
• 제12권4호
• /
• pp.392-397
• /
• 1991

A stereocontrolled synthesis of (${\pm}$)-isocomene (1) via selective monoketalization of tricyclo[6.3.0.$0^{1.5}$]undeca-4,7-dione(13) was reported. Grignard reaction of bicyclic enone 10, which was prepared from 2-methyl-1,3-cyclopentadione, gave the 1,4-addition product 11. The subsequent aldol condensation product 12 was converted to mesyl derivative 13. Transformation from 13 to the desired product 19 was achieved by a series of reactions, i.e., the selective monoketalization at C-4 carbonyl group, the elimination of a mesyl group, Birch alkylation, methylation at C-6, the reduction of carbonyl group, the dehydration of alcohol 18, and hydrolysis of the ketal group.

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

• 대한화학회지
• /
• 제64권1호
• /
• pp.7-18
• /
• 2020

An efficient and facile procedure has been developed for the synthesis of novel bichalcone derivatives (4a, 4b). The key step contains the solvent-free aldol synthesis of bichalcones based on quinones. Bichalcones (4a, 4b) were used as precursors for the synthesis of some interesting heterocyclic compounds like, diazepines (5a, 5b), pyrazolo-pyrimidines (7a, 7b), and pyrazoline derivatives (8a, 8b). Moreover, new thioxopyrimidine derivatives (9a, 9b) were furnished and used as a functionalizing agent to produce the triazole-pyrimidines (11, 12) and the carbonitrile derivative (14). All the synthesized compounds were fully characterized using physical and spectral data like, FT-IR, ¹H NMR, ¹³C NMR, and MS. Bichalcones (4a, 4b) and diazepines (5a, 5b) were screened for their anticonvulsant activity, where compounds (4a, 5a, and 5b) revealed potent anticonvulsant activity compared to diazepam. On the other hand, some of the prepared compounds were screened for their antiproliferative activity and they showed significant cytotoxic effects on most of the cancer cell lines with regard to broad spectrum antitumor activity.

• BMB Reports
• /
• 제31권2호
• /
• pp.130-134
• /
• 1998

An aldolase gene has been cloned from Methanococcus jannaschii. The coding region of the gene has been expressed in E. coli using a pET system to a level of 30% of total cellular proteins. The protein was purified to more than 95 % homogeneity by heat treatment and ion exchange chromatography. The protein performed an aldol condensation reaction with glyceraldehyde as substrate and dihydroxyacetone phosphate as a carboxyl donor. The protein was determined to be a type II aldolase which requires the $Zn^{2+}$ ion as a metal cofactor. This enzyme has a broad range of optimum pH (7-9) and temperature ($50-80^{\circ}C$). It shows strong stability against heat, chemical denaturants, as well as a high percentage' of organic solvents. The half-life of this enzyme at $85^{\circ}C$ is more than 24 h and it maintains more than 90% of aldolase activity in the presence of 6 M urea, 50% acetonitrile, or 15% isopropyl alcohol.

• Journal of Microbiology and Biotechnology
• /
• 제28권8호
• /
• pp.1339-1345
• /
• 2018

2-Keto-3-deoxy-6-phosphogluconate (KDPG) aldolase, which catalyzes aldol cleavage and condensation reactions, has two distinct substrate-binding sites. The substrate-binding mode at the catalytic site and Schiff-base formation have been well studied. However, structural information on the phosphate-binding loop (P-loop) is limited. Zymomonas mobilis KDPG aldolase is one of the aldolases with a wide substrate spectrum. Its structure in complex with the substrate-mimicking 3-phosphoglycerate (3PG) shows that the phosphate moiety of 3PG interacts with the P-loop and a nearby conserved serine residue. 3PG-binding to the P-loop replaces water molecules aligned from the P-loop to the catalytic site, as observed in the apostructure. The extra electron density near the P-loop and comparison with other aldolases suggest the diversity and flexibility of the serine-containing loop among KDPG aldolases. These structural data may help to understand the substrate-binding mode and the broad substrate specificity of the Zymomonas KDPG aldolase.

• Bulletin of the Korean Chemical Society
• /
• 제25권10호
• /
• pp.1545-1550
• /
• 2004

meso-Functionalized dipyrromethanes 6-10 were synthesized by acid-catalyzed addition of pyrrole to ${\alpha}$-position of 2-alkenyl pyrroles. The regiochemistry of the reaction can be explained by either the formation of more stable carbocation intermediate or ${\beta}$-addition of ${\alpha},{\beta}$-unsaturated carbonyl compounds. The starting 2-alkenyl pyrroles were synthesized by Aldol condensation of 2-formylpyrrole with active methylene compounds such as nitromethane, diethylmalonate and malononitrile. Attempted ‘2+2' condensation of meso-diethylmalonyldipyrromethane, meso-(p-tolyl)dipyrromethane and p-tolualdehyde afforded three different porphyrins 12, 13 and 14 in reasonable yields. On the other hand, meso-(nitromethyl)dipyrromethane with p-(tbutyl) benzaldehyde resulted in the formation of three different porphyrins such as 5,15-dicyano-10,20-diarylporphyrin (16), 5-cyano-15-formyl-10,20-diarylporphyrin (17) and 5,15-diformyl-10,20-diarylporphyrin (18) in low yields. Conversion of nitromethyl groups to nitrile and (or) formyl group was observed under the porphyrin forming conditions.

• Journal of Microbiology and Biotechnology
• /
• 제11권5호
• /
• pp.838-844
• /
• 2001

The enzyme Fuc aldolase from Methanococcus jannaschii that catalyzes the aldol condensation of DHAP and L-lactaldehyde to give fuculose-1-phosphate was inactivated by DEP. The inactivation was pseudo first-order in the enzyme and DEP, which was biphasic. A pseudo second-order rate constant of 120$M^{-1}min^{-1}$ was obtained at pH 6.0 and $25{\circ}C$. Quantifying the increase in absorbance at 240nm showed that four histidine residues per subunit were modified during the nearly complete inactivation. The statistical analysis and the time course of the modification suggested that two or three histidine residues were essential for activity. The rate of inactivation was dependent on the pH, and the pH inactivation data implied the involvement of the amino acid residue with a $pK_a$ value of 5.7. Fuc aldolase was protected against DEP inactivation by DHAP, indicating that the histidine residues were located at the active site of Fuc aldolase. DL-Glyceraldehyde, as an alternative substrate to L-lactaldehyde, showed no specific protection for the Fuc aldolase.

• Korean Chemical Engineering Research
• /
• 제53권6호
• /
• pp.802-807
• /
• 2015

본 논문에서는 글루코스산화제, polyethyleneimine(PEI) 및 탄소나노튜브 간 물리적 흡착으로 제조된 촉매(GOx/PEI/CNT)에 새로운 가교제인 terephthalaldehyde(TPA)를 첨가하여 민감도 및 안정성이 개선된 글루코스 센서 촉매를 합성하여, 감지능 및 안정성 개선효과를 확인하였다. 새로운 가교제를 포함한 바이오 촉매는, 글루코스산화제 및 polyethyeleneimine의 관능기와 TPA의 관능기간 알돌축합반응에 의해 생성되었고, 이를 통해 생성된 새로운 전자전달구조는 글루코스의 산화반응을 촉진시켰다. 이러한 촉매활성은 전기화학적 평가를 통해 정량적으로 평가하였으며 그 결과 $41.1{\mu}Acm^{-2}mM^{-1}$의 글루코스 민감도를 얻을 수 있었다. 또한 가교제와 글루코스산화제 및 polyethyeleneimine 간의 화학반응의 형성에 의해 글루코스 산화제의 외부 손실을 최소화 하여, 센서 안정성 향상에도 크게 기여하였다. 안정성 평가를 한 결과, 3주간의 주기적인 촉매 활성 측정후에 94.6% 활성이 유지됨을 확인하였다.