|
|
Development of an alternative synthesis of Sm-pdta, a chiral NMR shift reagent for amino acids analysis
Hrubá, Lucie ; Vaněk, Václav (advisor) ; Pohl, Radek (referee)
This bachelor thesis deals with the preparation of chiral shift reagents sodium [(R)- and (S)-1,2-diaminopropane-N,N,N',N'-tetraacetate]samarate, for short Sm-(R)-pdta and Sm-(S)-pdta. These reagents have the ability to differentiate NMR signals of enantiomers of amino acids in an aqueous environment. The main aim of this work was to develop a new, efficient and cheap method of the preparation of these reagents which would enable their routine use in laboratory practice, because these reagents are commercially available only in limited quantities and at high price. This work describes simplifield method of separation of racemic 1,2-diaminopropane to its enantiomers from easily available starting substances, L-tartaric acid and racemic 1,2-diaminopropane. We also developed and optimized a new process of synthesis of the key intermediate, (R)- and (S)-1,2-diaminopropane-N,N,N',N'-tetraacetic acid from (R)- and (S)-1,2-diaminopropane dihydrochloride, with a new synthetic step involving tetrabenzylester of this acid and its deprotection by hydrogenolysis without contamination by extraneous ions. This process affords very pure anhydrous acid in high yield. Finally, the target complexes Sm-(R)-pdta and Sm-(S)-pdta were successfully prepared from (R)- and (S)-1,2-diaminopropane-N,N,N',N'-tetraacetic acid...
|
|
| |
|
|
Development of an alternative synthesis of Sm-pdta, a chiral NMR shift reagent for amino acids analysis
Hrubá, Lucie ; Vaněk, Václav (advisor) ; Pohl, Radek (referee)
This bachelor thesis deals with the preparation of chiral shift reagents sodium [(R)- and (S)-1,2-diaminopropane-N,N,N',N'-tetraacetate]samarate, for short Sm-(R)-pdta and Sm-(S)-pdta. These reagents have the ability to differentiate NMR signals of enantiomers of amino acids in an aqueous environment. The main aim of this work was to develop a new, efficient and cheap method of the preparation of these reagents which would enable their routine use in laboratory practice, because these reagents are commercially available only in limited quantities and at high price. This work describes simplifield method of separation of racemic 1,2-diaminopropane to its enantiomers from easily available starting substances, L-tartaric acid and racemic 1,2-diaminopropane. We also developed and optimized a new process of synthesis of the key intermediate, (R)- and (S)-1,2-diaminopropane-N,N,N',N'-tetraacetic acid from (R)- and (S)-1,2-diaminopropane dihydrochloride, with a new synthetic step involving tetrabenzylester of this acid and its deprotection by hydrogenolysis without contamination by extraneous ions. This process affords very pure anhydrous acid in high yield. Finally, the target complexes Sm-(R)-pdta and Sm-(S)-pdta were successfully prepared from (R)- and (S)-1,2-diaminopropane-N,N,N',N'-tetraacetic acid...
|
|
|
Structure of an immunoactive polysaccharide isolated from Korean mulberry fruit (Morus alba L.)
Bleha, R. ; Lee, J. S. ; Capek, P. ; Pohl, Radek ; Kim, H. B. ; Choi, D. J. ; Lee, S. ; Lee, J. ; Jang, S. J. ; Synytsya, A. ; Park, Y. I.
A water-soluble polysaccharide (JS-MP-1) was isolated from the water extract of Korean white mulberry fruits (Morus alba L.) by ethanol precipitation and then purified by DEAE-cellulose ion exchange chromatography. Obtained final polysaccharide (1600 KDa) consisted of galactose, arabinose and rhamnose as major neutral sugars. JS-MP-1 also contains galacturonic and glucuronic acids (4:1). Sugar linkage, FTIR and correlation NMR analyses confirmed that it is a rhamnogalacturonan type I (RG I), which contains the alternating sequence of 1,4-alpha-D-GalAp and 1,2-alpha-L-Rhap units in the backbone. Neutral sugar side chains of JS-MP1 were identified as (1 -> 5)-alpha-L-arabinan and arabinogalactan type II (AG II) having the (1 -> 6)-beta-D-galactan core. The arabinan side chains are bound to the backbone at the O-4 position of some alpha-L-Rhap units, while the way of linkage between RG I and AG II chains is unclear. It was demonstrated that JS-MP-1 significantly stimulates murine macrophage RAW 264.7 cells to release chemokines (RANTES and MIP-1 alpha) and proinflammatory cytokines like INF-alpha and IL-6, and induce the iNOS and COX-2 gene expression, which are responsible for the production of NO and prostaglandin PGE2, respectively. These results suggest that JS-MP-1 can act as a potent immunomodulator and these observations may support the applicability of this polysaccharide or the water extracts of mulberry fruit can be used as an immunotherapeutic adjuvant or health beneficial food material.
|
|
| |
|
|
Pyrrolidine nucleotides conformationally constrained via hydrogen bonding
Pohl, Radek ; Poštová Slavětínská, Lenka ; Rejman, Dominik
Conformation of pyrroPME nucleotide analogues was studied by means of NMR at different pD values in D2O solutions. Surprisingly, two stable conformers were found at pD > 9 for both cis and trans configurations and their ratio depended on the acid-base properties of nucleobase attached to pyrrolidine ring. The results of conformational analysis suggest that the conformation of the pyrrolidine ring is locked via intramolecular hydrogen bond between negatively charged phosphonate oxygen atom and protonized pyrrolidine nitrogen.
|
|
| |
|
| |
|
| |
|
| |
guest ::
