110 research outputs found
Protection Studies Of Saccharomyces Cerevisiae Cells For The Use In Reduction Reactions In Organic Media [estudos De Proteção Da Célula De Saccharomyces Cerevisiae Para Utilização Em Reações De Redução Em Meio Orgânico]
No full textNew methodologies for protection of Saccharomyces cerevisiae (FP) cells when supported in montmorillonite K10 (K10), recovered or not with gelatin (G) and in the presence or absence of sucrose (S) are presented. These systems were used for the enantioselective reduction of ethyl acetoacetate and α-chloroacetophenone in hexane, under FP/K10/G/S and FP/S at 20°C during 24 hours, affording S-(+)-ethyl-3-hydroxybutanoate in 100% conversion and 99% ee, and R-(-)-2-chloro-1-phenylethanol 79% and 78% ee at 20 and 30°C, respectivelly.254567571Bon, E.P.S., Pereira N., Jr., (1999) Tecnologia Enzimática, p. 113. , Fundação Biblioteca NacionalRio de Janeiro, RJSantaniello, E., Ferraboschi, P., Grisenti, P., Manzocchi, A., (1992) Chem. Rev., 92, p. 1071Roberts, S.M., Turner, N.J., Willetts, J., Turner, M.K., (1995) Introduction to Biocatalysis using Enzymes and Micro-organisms, p. 195. , Cambridge University Press: New YorkHudlicky, T., Gonzalez, D., Gibson, D.T., (1999) Aldrichimica Acta, 32, p. 35Duran, N., De Conti, R., Rodrigues, J.A.R., (2000) Bol. Soc. Chil. Quim., 45, p. 109Stewart, J.D., (2000) Curr. Opin. Biotechnol., 11, p. 363Stanley, M.R., (2000) J. Chem. Educ., 77, p. 344Rotthaus, O., Krüger, D., Demuth, M., Schaffner, K., (1997) Tetrahedron, 53, p. 935Hudlicky, T., Gonzalez, D., Gibson, D.T., (1999) Aldrichimica Acta, 32, p. 35Fernadez-Lafuente, R., Armisén, P., Sabuquillo, P., Fernández-Lorente, G., Guisán, J.M., (1998) Chem. Phys. Lipids, 93, p. 185Narvátil, M., Sturdik, E., (1999) Biologia, 54, p. 635D'Arrigo, P., Fantoni, G.P., Servi, S., Strinti, A., (1997) Tetrahedron: Asymmetry, 8, p. 2375Hayakawa, R., Nozawa, K., Shimizu, M., Fujisawa, T., (1998) Tetrahedron Lett., 39, p. 67Pereira, R.S., (1998) Crit. Rev. Biotechnol., 18, p. 25Dahl, A.C., Madsen, J.O., (1998) Tetrahedron: Asymmetry, 6, p. 4395Bekatorou, A., Koutinas, A.A., Kaliafas, A., Kanellaki, M., (2001) Process Biochem., 36, p. 549Grunwald, P., (2000) Biochem. Educ., 28, p. 96Nakamura, K., Kondo, S., Kawai, Y., Ohno, A., (1991) Tetrahedron Lett., 32, p. 7075León, R., Fernandes, P., Pinheiro, H.M., Cabral, J.M., (1998) Enzyme Microb. Technol., 23, p. 483Jayasinghe, L.Y., Kodituwakku, D., Smallridge, A.J., Trewhella, M.A., (1994) Bull. Chem. Soc. Jpn., 67, p. 2528Nakamura, K., Kondo, S., Kawai, Y., Ohno, A., (1993) Bull. Chem. Soc. Jpn., 66, p. 2738Faber, K., (1997) Biotransformations in Organic Chemistry, p. 402. , Springer-Verlag: BerlinMedson, C., Smallridge, A.J., Trewhella, M.A., (1997) Tetrahedron: Asymmetry, 8, p. 1049Kanda, T., Miyata, N., Fukui, T., Kawamoto, T., Tanaka, A., (1998) Appl. Microbiol. Biotechnol., 49, p. 377Medson, C., Smallridge, A.J., Trewhella, M.A., (2001) J. Mol. Catal. B: Enzym., 11, p. 897Athanasiou, N., Smallridge, A.J., Trewhella, M.A., (2001) J. Mol. Catal. B: Enzym., 11, p. 893Dumanski, P.G., Florey, P., Knettig, M., Smallridge, A.J., Trewhella, M.A., (2001) J. Mol. Catal. B: Enzym., 11, p. 905Furniss, B.S., Hannaford, A.J., Rogers, V., Smith, P.W.G., Tatchell, A.R., (1978) Vogel's Textbook of Practical Organic Chemistry, 4 a ed., p. 353. , Longman Group Limited: New York(1979) Handbook of Chemistry and Physics, , CRC Press: Boca RatonSorrilha, A.E.P.M., Marques, M., Joekes, I., Moran, P.J.S., Rodrigues, J.A.R., (1992) Bioorg. Med. Chem. Lett., 2, p. 191Moran, P.J.S., Rodrigues, J.A.R., Joekes, I., Brenelli, E.C.S., Leite, R.A., (1994) Biocatalysis, 9, p. 321Wendhausen R., Jr., Moran, P.J.S., Joekes, I., Rodrigues, J.A.R., (1998) J. Mol. Catal. B: Enzym., 5, p. 69Brenelli, E.C.S., Carvalho, M., Okubo, M.T., Marques, M., Moran, P.J.S., Rodrigues, J.A.R., (1992) Indian J. Chem., 31 B, p. 821Barbieri, C., Bossi, L., D'Arrigo, P., Fantoni, G.P., Servi, S., (2001) J. Mol. Catal. B: Enzym., 11, p. 415Carvalho, M., Okamoto, M.T., Moran, P.J.S., Rodrigues, J.A.R., (1991) Tetrahedron, 47, p. 2073Aleixo, L.M., Carvalho, M., Moran, P.J.S., Rodrigues, J.A.R., (1993) Bioorg. Med. Chem. Lett., 3, p. 1637Moran, P.J.S., Rodrigues, J.A.R., Carvalho, M., De Brenelli, E.C.S., (1995) Atualidades de Físico Química Orgânica, p. 499. , Ed. E. Humeres: Florianópoli
Utilização de enzimas e microorganismos para a obtenção de compostos oticamente ativos
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Química.Neste trabalho foram exploradas metodologias alternativas de imobilização de enzimas e microrganismos para a manutenção das atividades e estereosseletividades dos mesmos em meio orgânico. As células de Saccharomyces cerevisiae (FP) foram suportadas em montmorilonita (K10), recobertas ou não com gelatina (G), na presença ou ausência de sacarose (S) ou trealose (T). Estes sistemas foram utilizados para a redução enantiosseletiva do acetoacetato de etila e a-cloroacetofenona em hexano. Para a redução do acetoacetato de etila com os sistemas FP/K10/G/S e FP/K10/G/T o biocatalisador tornou-se mais estável em meio orgânico, formaram-se menos subprodutos e a atividade foi mantida. O S-(+)-álcool foi obtido com ee>99% até a quarta reutilização, com valores de %c de 19 e 20% a 20oC, que foi a temperatura mais adequada para evitar a desativação das células. Para a biorredução do acetoacetato de etila constatou-se que a função principal da sacarose, da mesma forma que a trealose e a água, é de proteção da parede celular do microrganismo. Os valores de ee e %c foram similares com todos os sistemas. Na redução da a-cloroacetofenona obteve-se o R-(-)-2-cloro-1-feniletano após 72h de reação com ee 78-79%, quando o sistema FP/K10/G/S foi utilizado a 20 e 30oC, respectivamente. A biorredução em presença do sistema FP/K10/G/S forneceu %c superiores e valores de ee(%) inferiores aos obtidos em presença do sistema FP/K10/G/T (99%). Estes resultados evidenciam a influência da difusão para este reagente e produtos nos sistemas mais protegidos, ao contrário do observado para o acetoacetato de etila. O sistema FP/T foi o que apresentou a maior conversão em R-(-)-2-cloro-1-feniletanol e após 48h de reação obteve-se o produto com ee 80% e conversão de 45%, a 20oC. Para este substrato pode-se constatar o papel importante da trealose como agente protetor. O FP, imobilizado ou não, não foi eficiente quando utilizado como biorredutor de acetofenonas que não possuíam grupos ativantes próximos à carboníla, e os produtos desejados não foram obtidos
P2-purinergic stimulation of iodide efflux in FRTL-5 rat thyroid cells involves parallel activation of PLC and PLA2
No full textExtracellular ATP increases inositol phosphates, cytosolic Ca2+ concentration ([Ca2+]i), arachidonic acid (AA) release, and iodide efflux in FRTL-5 cells. To examine the sequence of events in P2-purinergic receptor activation by ATP, a phospholipase C (PLC) inhibitor (U-73122) and a phospholipase A2 (PLA2) inhibitor (U-26384), as well as 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'- tetraacetic acid (BAPTA) and downregulation of protein kinase C (PKC) were used. ATP increased inositol trisphosphate (IP3), [Ca2+]i, AA release, and 125I efflux dose dependently. U-73122 inhibited the IP3 and calcium increase but not AA; U-26384 prevented AA release but not the increase in calcium. Both agents inhibited iodide efflux. BAPTA prevented any ATP-induced increase in [Ca2+]i without affecting AA release or 125I efflux. PKC downregulation had no effect on ATP-stimulated AA release, but reduced 125I efflux. We conclude that ATP-induced iodide efflux involves parallel, not sequential, activation of PLC and PLA2. No increase in [Ca2+]i or PKC activity is required for PLA2 activation. In contrast, an increase in 125I efflux depends on PKC and PLA2 activities, but not an increase in [Ca2+]i.</jats:p
SAMA-AΩA Student Honors Day: Abstracts of Scientific Presentations
No full textMedical College of Virginia, May 1969. Summary includes: Mechanism of Baroreceptor-Induced Changes in Heart Rate by Marc D. Thames; Inhibition of Fibroplasia with Lung Implants in the Peritoneal Cavity of the Swiss White Mouse by Kenneth D. Youner; Roentgen Evaluation of the Hepatic Arterial Bed by Parham R. Fox; Effect of Gravity on the Distribution of Blood in the Dog Lung by David H. Bristow, Frank Martorano, and Battina Groome; A Study in CPK Iso-Enzymes by John Elwood Owens; Drug Usage in a Medical Ward by James B. Blitch and Jeffrey Biener; Acquired Absence of Alpha Lipoproteins and Acanthocytosis in Severely Burned Patients by Marvin Zelkowitz; Proteinuria and Glomerular Lesions in Rats Induced by Sera from Human Renal Transplant Recipients by R. C. Smallridge and D. B. Waldman
Heat shock increases cytosolic free Ca2+ concentration via Na(+)-Ca2+ exchange in human epidermoid A 431 cells
No full textThis study characterized cytosolic free Ca2+ concentration ([Ca2+]i) in normal and thermally injured human epidermoid A 431 cells. The resting [Ca2+]i in normal cells at 37 degrees C was 87 +/- 5 nM (n = 105). When cells were subjected to hyperthermia (40-50 degrees C), [Ca2+]i increased in a temperature- and time-dependent manner. The maximal increase in cells exposed to 45 degrees C was observed at 20 min; [Ca2+]i returned to normal within 1 h. The heat-induced [Ca2+]i increase depended on the presence of external Ca2+. La3+ and Cd2+ but not Co2+, verapamil, or nifedipine attenuated the heat-induced [Ca2+]i increase. TMB-8 partially blocked the increase in [Ca2+]i but pertussis toxin and cholera toxin pretreatment did not. The magnitude of the heat-induced [Ca2+]i increase or 45Ca2+ uptake depended on the presence of extracellular Na+. Heat treatment reduced the apparent Michaelis constant for external Ca2+ from 490 +/- 91 to 210 +/- 60 microM, whereas the maximal velocity remained the same. The intracellular Na+ concentration decreased 62.5% after heating. The heat-induced [Ca2+]i increase was completely blocked by amiloride (5 microM) and 5'-(N,N-dimethyl)-amiloride (1 microM). These results suggest heat activates the Na(+)-Ca2+ exchange system so as to increase [Ca2+]i and reduce [Na+]i.</jats:p
Preparation of multinuclear Ruthenium Vinylidene Complexes and Their Deprotonation Reactions
No full text將Cp(PEt3)2RuCl與過量之苯基乙炔和KPF6在甲醇中反應可得單取代之釕金屬亞乙烯基化合物2，藉由去質子反應可製得釕金屬炔化合物3。一系列具有不同官能基之雙取代陽離子性釕金屬亞乙烯基化合物4a~4g可藉由化合物3和不同的一級鹵烷類在二氯甲烷中反應而得。針對單核釕金屬亞乙烯基化合物4a~4g進行去質子反應成功的合成出中性釕金屬環丙烯基錯合物5a、5b、5f 和釕金屬呋喃錯合物6d、6g。
化合物4c和Cp(PR3)2RuCl以一比一的比例在過量KPF6的存在下可製得雙核釕金屬亞乙烯基化合物7w和7x，藉由去質子反應可由7w和7x得到雙核亞乙烯基炔化合物8w和8x。以化合物8w和8x針對不同官能基之一級鹵烷類在二氯甲烷中進行反應可得一系列帶二價正電荷之雙核釕金屬亞乙烯基化合物9w~15w和9x~13x，15x。
針對帶二價正電荷之雙核釕金屬亞乙烯基化合物進行去質子反應發現了一個有趣的結果，依據第二個金屬上phosphine 取代基推拉電子的特性，可造成不同的環化反應，當第二個金屬上phosphine 取代基是推電子的特性時，化合物16w經由去質子反應可得新型雙金屬五員環錯合物，如是拉電子特性時，先得新型五員環錯合物16x 為中間物，最後再異構化為雙金屬三員環錯合物18x。在化合物13w 和13x 的去質子反應中，我們也發現同樣的結果。
我們也藉由化合物11w 的結構特性，運用類似的反應條件，成功地將系統延伸到三金屬化合物，順利的合成出三核亞乙烯基化合物21。Treatment of [Ru]-Cl, [Ru] = CpRu(PEt3)2, with phenylacetylene in the presence of KPF6 in methanol affords [Ru]=C=C(H)Ph+ (2) and then deprotonation of 2 by MeONa yields complex [Ru]-C≡C-Ph (3) isolated as yellow solid in high yield. Reactions of 3 with various organic halides in the presence of KPF6 yield corresponding air stable cationic vinylidene complexes [Ru]=C=C(Ph)CH2R+ (4a, R = CH=CH2; 4b, R = CN; 4c, R = C≡CH; 4d, R = CO2Me; 4e, C≡C(SiMe3); 4f, R = Ph; 4g, R = COOEt), respectively, all in high yield. Deprotonation of mononuclear cationic vinylidene complexes of ruthenium [Ru]=C=C(Ph)CH2R (4a, R = CH=CH2, 4b, R = CN, 4f, R = Ph) yields corresponding cyclopropenyl complexes [Ru]-C=C(Ph)CHR (5a, R = CH=CH2, 5b, R = CN, 5f, R = Ph) in high yield. The neutral ruthenium furyl complexes [Ru]-C=C(Ph)CH=C(O)OR, (6d, R = Me; 6g, R = Et) are also prepared by deprotonation of corresponding ruthenium vinylidene complexes containing an ester group at Cγ.
Reaction of the terminal alkynyl group of 4c with [Ru’]-Cl in the presence of KPF6 affords the bisvinylidene complexes [Ru]=C=C(Ph)CH2C(H)=C=[Ru’], (7w, [Ru’] = CpR (PEt3)2; 7x, [Ru’] = CpRu(PPh3)2) which deprotonated to give the alkynyl,vinylidene complexes [Ru]=C=C(Ph)CH2C≡C-[Ru’], (8w, [Ru’] = CpRu(PEt3)2; 8x, [Ru’] =
CpRu(PPh3)2 in the presence of base. Alkylation of complex 8w with various primary alkyl halide affords the corresponding cationic ruthenium bisvinylidene complexes[Ru]=C=C(Ph)CH2C(CH2R)=C=[Ru’], ([Ru’] = CpRu(PEt3)2; 9w, R = CH=CH2; 10w, R = CN; 11w, R = C≡CH; 12w, R = CO2Me; 13w, R = COOEt; 14w, R = Ph; 15w, R = C≡C(SiMe3)). Complexes 9x, 10x, 11x, 12x, 13x, 15x are also successfully obtained by the same synthetic strategy. Deprotonation of the dinuclear dicationic vinylidene complex {[Ru]=C=C(Ph)CH2C(CH2CN)=C=[Ru’]}2+ (10w) by n-Bu4NOH is also followed by a cyclization process, however, yielding the distinctive stable complex 16w containing a five-membered carbocyclic ring ligand which is fully characterized by 2D-NMR analysis and single crystal X-ray diffraction analysis. Deprotonation of {[Ru]=C=C(Ph)CH2C(CH2COOEt)=C=[Ru’]}2+ (13w) similarly gave the stable product 17w containing a bridging ligand also with the same five-membered carbocyclic ring. Interestingly, analogous dinuclear complex 16x with bistriphenylphosphine ligand on one metal, which is prepared in a similar manner
from {[Ru]=C=C(Ph)CH2C(CH2CN)=C=[Ru’]}2+ (10x), however, is unstable undergoing isomerization to give the dinuclear complex 18x containing cyclopropenyl ligand.
The reaction of 11w with [Ru”]-Cl, [Ru”] = CpRu(PEt3 2, gives the trinuclear trisvinylidene complex 21 which undergoes deprotonation to give the trinuclear bisvinylidene acetylide complex 22 characterized by spectroscopic method. Treatment of complex 1 with 1,1 diphenyl-2-propyn-1-ol yields the cationic ruthenium allenylidene complex [Ru]=C=C=C(Ph)2+, (30, [Ru] = CpRu(PEt3)2), in high yield which reacts with Grignard reagent RCH2MgBr in THF affords the neutral ruthenium acetylide complexes [Ru]-C≡C-C(Ph)2CH2R, (31a, R = CH=CH2; 31b, R =
C≡CH). Complexes 30 undergo protonation reactions giving the corresponding vunylidene complexes [Ru]=C=C(H)-C(Ph)2CH2R+, (32a, R = CH=CH2; 32b, R = C≡CH). Unfortunately, no transformation of complexes 32 in solution is observed
indicating the reactivity of complexes 32a and 32b is different from that reported previously.
A number of cationic ruthenium isocyanide complexes [Ru]-CNCH2R+, ([Ru] = CpRu(PEt3)2; 41a, R = Ph; 41b, R = C≡CH) are prepared by alkylation of Ru cyano complex 40 with corresponding alkyl halide. Treatment of complex 41a with base in acetone cause the formation of ruthenium oxazolinyl complex Cp(PEt3)2RuCNCH(Ph)C(Me)2O (43). Complex 41a also reacts with benzaldehyde in CH2Cl2 to afford another ruthenium oxazolinyl complex Cp(PEt3)2RuCNCH(Ph)C(Ph)HO (44).CONTENTS
Structure and Numbering of Complexes
Reaction Scheme
Abstract
Chapter 1 Introduction 1
1-1 Metal Vinylidene Complexes
1-2 Cyclopropene and Metal Cyclopropenyl Complexes
1-3 Azirine and Metal Azirinyl Complexes
Chapter 2 Cp Ruthenium Cyclopropenyl and Furyl Complexes from Ruthenium Vinylidene Complexes 10
2-1 Synthesis of Mononuclear Cp Ruthenium Acetylide Complexes
2-2 Synthesis of Mononuclear Ruthenium Vinylidene Complexes
2-3 Synthesis of Mononuclear Ruthenium Cyclopropenyl Complexes
Chapter 3 Preparation of multinuclear Ruthenium Vinylidene
Complexes and Their Deprotonation reactions 22
3-1 Preparation of Dinuclear Ruthenium Vinylidene Acetylide Complexes
3-2 Preparation of Dinuclear Ruthenium Vinylidene Complexes
3-3 Preparation of Other Dinuclear Ruthenium Vinylidene Complexes
3-4 Preparation of Trimetallic Complexes
3-5 Deprotonation Reactions of Dinuclear Ruthenium Vinylidene Complexes
3-6 Preparation of Other Dinuclear Ruthenium Vinylidene Acetylide Complexes
Chapter 4 Preparation and Characterization of Ruthenium
Allenylidene Complexes and Related Ruthenium
Vinylidene Complexes 65
4-1 Synthesis of Ruthenium Acetylide Complexes
4-2 Synthesis of Ruthenium Vinylidene Complexes
4-3 Reactivity of Ruthenium Vinylidene Complexes
Chapter 5 Ruthenium Isocyanide Complexes and Related
Reactions 74
5-1 Preparation of Ruthenium Cyanide Complexes
5-2 Preparation of Ruthenium Isocyanide Complexes
5-3 Deprotonation of Ruthenium Isocyanide Complexes
5-4 Reaction of Isocyanide Complex with Benzaldehyde
Chapter 6 Concluding Remark 88
Chapter 7 Experimental Section 90
References 13
Anaplastic thyroid carcinoma
No full textAnaplastic thyroid carcinoma (ATC) is a highly aggressive thyroid malignancy composed of undifferentiated follicular thyroid cells
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