Change search
ReferencesLink to record
Permanent link

Direct link
Coupling of substances containing a primary amine to hyaluronan via carbodiimide-mediated amidation
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
2010 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

The purpose of this study was to investigate the carbodiimide-mediated amidation of hyaluronan (HA). The carbodiimide-mediated amidation includes the formation of a urea derivative, O-acylisourea, between the carbodiimide and a carboxylic group of HA, which a primary amine can displace, resulting in an amide bond. Reaction conditions were investigated and optimized, the molecular weights Mn and Mw were determined with size-exclusion chromatography and by-products were analysed with 1H NMR. The reaction is done at room temperature in slightly acidic pH, giving a degree of substitution between 5 to 15 %. A catalyst, N-hydroxysuccinimide, was needed for the coupling to be successful, since O-acylisourea was shown not to be reactive enough towards primary amines. It was found out that dissociated primary amines successfully couple to HA, contrary to what has been suggested before. 1H NMR revealed that O-acylisourea readily forms a by-product, which is covalently attached to HA, through the means of rearrangement. Also, 1H NMR showed that the carbodiimide reacts with phenols. An increase of Mn and Mw compared with native HA was observed and attributed to ester bond formation between a hydroxyl- and carboxylic group of HA polysaccharides. To conclude, the carbodiimide-mediated amidation is an unspecific reaction which is not suited for the coupling of primary amines to HA.

Place, publisher, year, edition, pages
2010. , 44 p.
Series
UPTEC K, ISSN 1650-8297 ; 11002
Keyword [en]
carbodiimide, hyaluronan, optimization, EDC, NHS, tyramine
Identifiers
URN: urn:nbn:se:uu:diva-149284OAI: oai:DiVA.org:uu-149284DiVA: diva2:404392
Uppsok
Technology
Supervisors
Examiners
Available from: 2011-03-24 Created: 2011-03-16 Last updated: 2011-03-24Bibliographically approved

Open Access in DiVA

fulltext(1647 kB)19035 downloads
File information
File name FULLTEXT03.pdfFile size 1647 kBChecksum SHA-512
5905e7569452d5a6306a88dd0cf7da4adef2ed1c3559e58f5e0498ff8eb6b2c3d453340f10d4b47f9e135d4d9001e2ae07408040f0a638f0463d840051db19e8
Type fulltextMimetype application/pdf

By organisation
Department of Biochemistry and Organic Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 19035 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 679 hits
ReferencesLink to record
Permanent link

Direct link