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1.
Pyridoxylated hemoglobin derivatives have been studied by many investigators. In this study hemoglobin A0 rather than stroma-free hemoglobin was used as a starting material in order to reduce the number of proteins to A0 and A1c. Derivatives were characterized using a Synchropak Q300 strong anion-exchange column, a PolyCAT A weak cation-exchange column and a VYDAC reversed-phase high-performance liquid chromatographic column. Resulting peak profiles of these two ion-exchange separations demonstrated enhanced resolution and showed the presence of pyridoxylated hemoglobin products not previously described. We compared products from the reduction of these Schiff base derivatives using either sodium borohydride or sodium cyanoborohydride reduction procedures. The sodium cyanoborohydride reduction method produced a lower percentage of products with multiple-site pyridoxylation modifications than the sodium borohydride reduction process. 相似文献
2.
The effect of borohydride reducing reagents on monoclonal and polyclonal antibodies was examined by enzyme-linked immunosorbent
assay (ELISA). Each antibody showed different stability characteristics to the reducing reagents. Sodium cyanoborohydride
was at least five times milder toward immunological activity than sodium borohydride, however, sodium cyanoborohydride with
a catalytic amount of metal ion (Zn2+ or Al3+ ) can be as harsh as sodium borohydride. Activated hydrophobic borohydrides, 9BBN-pyridine, did not have any advantages in
respect to the stabilities of antibodies. Antibodies to be used for immunosorbent purification must be evaluated individually
to determine whether their structure is stable to immobilization reagents and conditions prior to their linkage to the column
support. 相似文献
3.
Rhonda S. Bayoud Edward R. Biehl Perry C. Reeves 《Journal of organometallic chemistry》1979,174(3):297-303
A series of pentadienyliron tricarbonyl cations has been prepared and reacted with the hydride ion donors sodium borohydride, sodium cyanoborohydride, and lithium triethylborohydride in order to determine steric and electronic effects in these reduction reactions. Sodium cyanoborohydride yields products of retained configuration whereas lithium triethylborohydride yields dieneiron tricarbonyl compounds of inverted configuration. Kinetic and thermodynamic considerations are used to account for these results. 相似文献
4.
Stereoselective sodium borohydride reduction of the 8,14-cycloberbine (9) derived from the protoberberine (7), followed by reductive cleavage of C8-N bond of the resulting 13-hydroxy-8, 14-cycloberbine (10) with sodium cyanoborohydride afforded the spirobenzylisoquinoline (12), N-methylation of which via the oxazolidine (13) provided (±)-dihydrofumariline-l (1). 相似文献
5.
Myung Hee Jung Jewn-Giew Park Bok-Sim Ryu Kui-Woong Cho 《Journal of heterocyclic chemistry》1999,36(2):429-434
2-Pyridin-3-ylbenzoxazoles were synthesized by the reaction between 3-pyridinecarboxaldehyde and substituted o-aminophenols in the presence of iodobenzene diacetate. The resulting benzoxazoles 3 were treated with methyl iodide to give the corresponding pyridinium salts 4 which underwent the hydride reduction with sodium borohydride or sodium cyanoborohydride to produce 2-(1-methyl-1,2,5,6-tetrahy-dropyridin-3-yl)benzoxazole borane complex derivatives. 相似文献
6.
A series of 3-substituted-3-chloro-2-propeniminium salts have been reacted with sodium borohydride and/or sodium cyanoborohydride to produce 1-substituted-1-chloro-3-N, N-dimethylamino-1-propenes in good yield. 相似文献
7.
V. A. Slavinskaya G. I. Chipens M. Yu. Katkevich D. É. Sile É. Kh. Korchagova V. D. Grigor'eva É. Lukevits 《Chemistry of Heterocyclic Compounds》1996,32(4):405-407
A method has been developed for the synthesis of N-(1-carboxy-3-phenylpropen-2-yl)atanylproline by reductive alkylation of alanylproline by the sodium salt of 2-oxo-4-phenylbutenoic acid, using sodium cyanoborohydride and sodium borchydride as reducing agents. The products were separated chromatographically. Under the conditions of the reaction, sodium borohydride in a neutral medium preferentially reduces the double bond of the Schiff base. Sodium cyanoborohydride reduces, in addition, the double bond of the 2-oxo-4-phenylbutenoic acid, forming enalaprilate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 468–471, April, 1996. 相似文献
8.
Abstract: Fluorinated benzylamines are synthesized in high yields by reductive alkylation of secondary amines with appropriate fluoroaldehydes using a combination of zinc chloride and zinc borohydride. The present method offers an alternative to toxic sodium cyanoborohydride and is adaptable to multigram-scale preparations. 相似文献
9.
Reduction is a fundamental transformation in organic synthesis. Since its discovery by Brown and co‐workers, sodium borohydride is the most frequently hydride used in reduction processes. Owing to the importance of this reagent in modern organic synthesis, the aim of this review is to highlight recent methodologies (2000–2006) mediated by sodium borohydride in the reduction of different classes of compounds. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
10.
以硼氢化钠为还原剂化学镀镍的电化学研究 总被引:1,自引:0,他引:1
采用线性电位扫描伏安法研究了以硼氢化钠为还原剂的化学镀镍体系, 考查了镀液组成及工艺条件对化学镀镍硼阴、阳极过程的影响, 结果表明: 乙酸镍和硼氢化钠含量的提高分别促进了Ni2+的还原反应和BH4-的氧化反应; 乙二胺、氢氧化钠以及添加剂硫脲、糖精钠对阴、阳极反应均有不同程度的抑制作用, 同时添加剂中的硫元素加速了镍的氧化; 升高温度有利于阴、阳极反应的进行. 相似文献
11.
V. M. Kisel L. M. Potikha A. V. Turov V. A. Kovtunenko 《Chemistry of Heterocyclic Compounds》2001,37(9):1153-1161
Borohydride reduction in a series of 7-benzyl- and newly synthesized 7-arylmethylene-7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones leads stereoselectively to erythro-7-benzyl-6,6a,7,12-tetrahydro-5H-isoquino[2,3-a]quinazolin-5-ones. 7,7-Disubstituted 7,12-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones are inert to the action of sodium borohydride, but spiro[5H-isoquino[2,3-a]quinazolin-7(12H),2'-indane]-5-one is reduced under rigid conditions to 6,6a-dihydrospiro[5H-isoquino[2,3-a]quinazolin-7(12H),2'-indan]-5-one. 7-Acetyl- and 7-benzoyl-6,11-dihydro-5H-isoquino[2,3-a]quinazolin-5-ones are converted in an aqueous alcoholic solution of sodium borohydride to the previously described 6,6a,7,12-tetrahydro-5H-isoquino[2,3-a]quinazolin-5-one. The structure and special features of the conformational behavior of the reduction products obtained were demonstrated by 1H NMR spectroscopy.! 相似文献
12.
Christopher R. Butler Justin Bendesky Allen Milton Schoffstall 《Molecules (Basel, Switzerland)》2021,26(18)
Regioselective reactions can play pivotal roles in synthetic organic chemistry. The reduction of several 1-substituted 1,2,3-triazole 4,5-diesters by sodium borohydride has been found to be regioselective, with the C(5) ester groups being more reactive towards reduction than the C(4) ester groups. The amount of sodium borohydride and reaction time required for reduction varied greatly depending on the N(1)-substituent. The presence of a β-hydroxyl group on the N(1)-substituent was seen to have a rate enhancing effect on the reduction of the C(5) ester group. The regioselective reduction was attributed to the lower electron densities of the C(5) and the C(5) ester carbonyl carbon of the 1,2,3-triazole, which were further lowered in cases involving intramolecular hydrogen bonding. 相似文献
13.
In the presence of sodium borohydride, esters react with alcohols with formation of the corresponding esters. The reaction is sensitive to the solvent, structure of the ester, and is often concurrent with reduction. Thioesters containing an ester group can be selectively cleaved by the reagent. Both esters and thioesters attached to solid support are resistant toward sodium borohydride. The in situ prepared sodium tetraalkoxyborate is introduced as an efficient reagent and catalyst for transesterification. 相似文献
14.
Carboxylic acids are converted into corresponding alcohols by chemoselective reduction of their benzotriazole amides with sodium borohydride. 相似文献
15.
Metal Nanoparticle‐Catalyzed Reduction Using Borohydride in Aqueous Media: A Kinetic Analysis of the Surface Reaction by Microfluidic SERS 下载免费PDF全文
Dr. Wei Xie Roland Grzeschik Prof. Sebastian Schlücker 《Angewandte Chemie (International ed. in English)》2016,55(44):13729-13733
Hydrides are widely used in reduction reactions. In protic solvents, their hydrolysis generates molecular hydrogen as a second reducing agent. The competition between these two parallel reduction pathways has been overlooked so far since both typically yield the same product. We investigated the platinum‐catalyzed reduction of 4‐nitrothiophenol to 4‐aminothiophenol in aqueous sodium borohydride solution as a prominent model reaction, by using label‐free SERS monitoring in a microfluidic reactor. Kinetic analysis revealed a strong pH dependence. Surprisingly, only at pH>13 the reduction is driven exclusively by sodium borohydride. This study demonstrates the potential of microfluidics‐based kinetic SERS monitoring of heterogeneous catalysis in colloidal suspension. 相似文献
16.
The reduction of pyridoindole derivative 1 by sodium borohydride in methanol gives 4,5-dihydropyridoindole 2. On treatment of 5H-pyrido[3,2-b]indolium chloride 3 with sodium cyanoborohydride in methanol in the presence of hydrogen chloride, reduction of the pyridine ring is accompanied
by reduction of the CN group, resulting in the formation of tetrahydropyridoindole 4. Compound 4 reacts with DMF dimethyl acetal to yield amidine 6, and refluxing of 4 with acetic anhydride results in tetrahydropyridine ring cleavage yielding indolylacrylonitrile 9. The hydrochloride and chloride of compounds 4 and 6 were obtained 相似文献
17.
Takushi Nagata Kiyoaki D. Sugi Kiyotaka Yorozu Tohru Yamada Teruaki Mukaiyama 《Catalysis Surveys from Japan》1998,2(1):47-57
Optically active aldiminato cobalt(II) complexes have been found to catalyze the enantioselective reduction of ketones with sodium borohydride affording the corresponding optically active secondary alcohols in high chemical yields with high enantioselectivities. The enantioselective borohydride reduction is also applicable to not only C=O bonds in aromatic ketones but also to C=N bonds in aromatic imines. 相似文献
18.
Sanjib Gogoi 《Tetrahedron》2004,60(41):9093-9097
Starting from citraconic anhydride (2), a six step synthesis of leaf closing substance (±)-erythro potassium 2,3,4-trihydroxy-2-methyl-butanoate (1) has been described with 29% overall yield via diesterification, OsO4-dihydroxylation, acetonide protection, regioselective mono hydrolysis of unhindered ester moiety, borane-dimethylsulfide induced chemoselective reduction of carboxylic group and hydrolysis pathway. Surprisingly, the sodium borohydride reduction of monoester 5 and lithium borohydride reduction of 11 furnished the undesired regioisomer 7. 相似文献
19.
Núbia Boechat Jorge Carlos Santos da Costa Jorge de Souza Mendonça Karla Ceodaro Paes Elisa Lopes Fernandes Pedro Santos Mello de Oliveira 《合成通讯》2013,43(24):3187-3190
Some heteroaromatic esters were reduced to the corresponding alcohols by using a sodium borohydride–methanol system. The reduction was completed within 0.15–2.0 h in refluxing THF. The alcohol products were isolated after aqueous workup in moderate to excellent yield (48–97%). 相似文献
20.
Alejandra Salerno Vanina Ceriani Isabel A. Perillo 《Journal of heterocyclic chemistry》1992,29(7):1725-1733
Reactions of several substituted 1H-4,5-dihydroimidazolium salts 1 with nucleophilic and electrophilic reducing agents acting via hydride transfer were explored. Reaction of compounds 1 with lithium aluminum hydride in THF afforded the corresponding imidazolidines 2 . When alkaline borohydrides (sodium borohydride, potassium borohydride, sodium cyanoborohydride) in ethanol at room temperature were used, partial or total over-reduction of compounds 2 leading to N,N,N'-trisubstituted ethylenediamines took place on occasion. Results may be explained taking into account that reductive cleavage of 2 proceeds via a stabilized iminium ion present in protic solvents. Treatment of compounds 1 with an excess of borane in THF afforded the corresponding imidazolidines 2 or their borane complexes, according to the substituent type. 相似文献