scholarly journals An amphiphilic, catalytically active, vitamin B12 derivative

2014 ◽  
Vol 50 (36) ◽  
pp. 4674-4676 ◽  
Author(s):  
M. Giedyk ◽  
S. N. Fedosov ◽  
D. Gryko
Keyword(s):  
Vitamin B12 ◽  
Vitamin B ◽  
Active Vitamin ◽  
Bond Forming ◽  
Bond Forming Reactions ◽  
Catalytically Active

The reaction of vitamin B12 with DMF-DMA and MeOH as a nucleophile affords cobalester, the first amphiphilic cobalamin derivative which is able to catalyze C–C bond forming reactions.

scholarly journals Feeding dried purple laver (nori) to vitamin B12-deficient rats significantly improves vitamin B12 status

2001 ◽  
Vol 85 (6) ◽  
pp. 699-703 ◽  
Author(s):  
Shigeo Takenaka ◽  
Sumi Sugiyama ◽  
Shuhei Ebara ◽  
Emi Miyamoto ◽  
Katsuo Abe ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Intrinsic Factor ◽  
Porphyra Yezoensis ◽  
Dry Weight ◽  
Biologically Active ◽  
Vitamin B ◽  
Acid Excretion ◽  
Active Vitamin ◽  
Total Vitamin

To clarify the bioavailability of vitamin B12 in lyophylized purple laver (nori; Porphyra yezoensis), total vitamin B12 and vitamin B12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B12-deficient rats were investigated. The amount of total vitamin B12 in the dried purple laver was estimated to be 54.5 and 58.6 (SE 5.3 and 7.5 respectively) ΜG/100 g dry weight by lactobacillus bioassay and chemiluminescent assay with hog intrinsic factor respectively. the purple laver contained five types of biologically active vitamin b12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin b12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin b12. when 9-week-old vitamin b12-deficient rats, which excreted substantial amounts of methylmalonic acid (71.7(se 20.2) μmol/d) in urine, were fed the diet supplemented with dried purple laver (10 μg/kg diet) for 20 d, urinary methylmalonic acid excretion (as an index of vitamin B12 deficiency) became undetectable and hepatic vitamin B12 (especially adenosylcobalamin) levels were significantly increased. These results indicate that vitamin B12 in dried purple laver is bioavailable to rats.

Recent Advances on C-Se Bond-forming Reactions at Low and Room Temperature

2020 ◽  
Vol 23 (28) ◽  
pp. 3206-3225 ◽  
Author(s):  
Amol D. Sonawane ◽  
Mamoru Koketsu
Keyword(s):  
Room Temperature ◽  
Bond Formation ◽  
Bond Forming ◽  
Material Chemistry ◽  
Recent Advances ◽  
Bond Forming Reactions ◽  
Bond Formation Reactions

: Over the last decades, many methods have been reported for the synthesis of selenium- heterocyclic scaffolds because of their interesting reactivities and applications in the medicinal as well as in the material chemistry. This review describes the recent numerous useful methodologies on C-Se bond formation reactions which were basically carried out at low and room temperature.

Graphene Oxide and Its Derivatives: Their Synthesis and Use in Organic Synthesis

2019 ◽  
Vol 23 (2) ◽  
pp. 188-204 ◽  
Author(s):  
Xiangjun Peng ◽  
Xianyun Xu ◽  
Fujiang Huang ◽  
Qian Liu ◽  
Liangxian Liu
Keyword(s):  
Graphene Oxide ◽  
Carbon Materials ◽  
Device Fabrication ◽  
Organic Reactions ◽  
Bond Forming ◽  
Bond Forming Reactions ◽  
Modern Physics ◽  
Recent Developments ◽  
Optical And Mechanical Properties ◽  
Nitrogen Double Bond

Since Geim and co-workers reported their groundbreaking experiments on graphene, research on graphene oxide (GO) and its derivatives has greatly influenced the field of modern physics, chemistry, device fabrication, material science, and nanotechnology. The unique structure and fascinating properties of these carbon materials can be ascribed to their eminent chemical, electronic, electrochemical, optical, and mechanical properties of GO and its derivatives, particularly compared to other carbon allotropes. The present Review aims to provide an overview on the recent developments in the preparation of GO and its derivatives and their applications in organic reactions. We will first outline the synthesis of GO and its derivatives. Then, we will discuss the major sections about their application as stoichiometric and catalytic oxidants in organic reactions, a particular emphasis on the carbon-carbon, carbon-oxygen, and carbon-nitrogen single bond-forming reactions, as well as carbon-oxygen and carbon-nitrogen double bond-forming reactions. Simultaneously, this Review also describes briefly transition metal supported on GO or its derivatives as a catalyst for organic reaction. Lastly, we will present an outlook of potential areas where GO and its derivatives may be expected to find utility or opportunity for further growth and study.

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

scholarly journals Borane Catalysed Cyclopropenation of Arylacetylenes

2021 ◽  
Author(s):  
Katarina Stefkova ◽  
Matthew Heard ◽  
Ayan Dasgupta ◽  
Rebecca Melen
Keyword(s):  
Catalytic Activities ◽  
Bond Forming ◽  
Bond Forming Reactions

Triarylboranes have gained substantial attention as catalysts for C–C bond forming reactions due to their remarkable catalytic activities. Herein, we report B(C6F5)3 catalysed cyclopropenation of a wide variety of arylacetylenes...

scholarly journals Molecularly imprinted membrane for transport of urea, creatinine, and vitamin B12 as a hemodialysis candidate membrane

2021 ◽  
Vol 19 (1) ◽  
pp. 806-817
Author(s):  
Muhammad Cholid Djunaidi ◽  
Nabilah Anindita Febriola ◽  
Abdul Haris
Keyword(s):  
Polyethylene Glycol ◽  
Vitamin B12 ◽  
Kidney Function ◽  
Cross Linking ◽  
Vitamin B ◽  
Molecularly Imprinted ◽  
Selective Transport ◽  
Molecularly Imprinted Membrane ◽  
Better Than ◽  
Imprinted Membrane

Abstract High levels of urea and creatinine in the blood are a sign of decreased kidney function. To remove these substances from the blood, hemodialysis which utilizes membranes could be used. In this study, a molecularly imprinted membrane (MIM) was synthesized for the selective transport of urea. The synthesis is initiated with the polymerization of eugenol into polyeugenol and then into polyeugenoxy acetate (PA). The PA is then contacted with urea and then used as the functional polymer in the synthesis of MIM with polysulfone as the membrane base, and polyethylene glycol as the cross-linking agent. The result was later analyzed with FTIR and SEM-EDX. The membrane is then used in the transport of urea, creatinine, and vitamin B12 and then compared with the non-imprinted membrane (NIM) performance. By using UV-Vis spectrophotometry, the results showed that the membrane with 10 h heating variation is able to transport more urea and is more selective than NIM; this proves that the urea template on the MIM enables it to recognize urea molecules better than creatinine and vitamin B12. The order of transport from the best results is urea > creatinine > vitamin B12.

Röntgenspektroskopische Bestimmung der Wertigkeit des Kobalts im Vitamin B12

1954 ◽  
Vol 9 (8) ◽  
pp. 509-513 ◽  
Author(s):  
G. Boehm ◽  
A. Faessler ◽  
G. Rittmayer
Keyword(s):  
Vitamin B12 ◽  
Vitamin B

Mit einem fokussierenden Spektrographen großer Dispersion wird die Lage der K-Röntgen-absorptionskante des Kobalts in verschiedenen Verbindungen untersucht. Die Ergebnisse zeigen, daß es möglich ist, durch Bestimmung der Kantenlage die Wertigkeit des Kobalts in einer Verbindung zu bestimmen. Die Methode gestattet den eindeutigen Nachweis, daß das Kobalt im Vitamin B12 dreiwertig ist.

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