Cyclopropene Derivatives for the Photoclick Reaction

PS1 Poster session 1 Odd numbers
Location (hall): 
Start/end time: 
Monday, July 1, 2019 - 15:45 to 17:15
Mareike Astrid

Mareike Astrid Rapp1, Christopher Hassenrück1, Valentin Wittmann1

1Universität Konstanz, Konstanz, Germany

Metabolic glycoengineering has been established as a highly valuable tool to non-destructively investigate glycosylation.[1-3] In previous studies we found that Ac₄ManNAcryl (1) reacts well in the nitrile imine photoclick reaction and not in the DAinv reaction, and that Ac₄ManNCyoc (2) as well as Ac₄ManNCp (3) react very well in the DAinv reaction, thus a orthogonality of these bioorthogonal ligation reactions is possible.[4, 5] To gain better insight into the photoclick reaction and to simplify analytics, two cyclopropene model compounds (CHexNCyoc (4) and CHexNCp (5)) were synthesized. 4 and 5 were reacted with Tet-1 (6) and Tet-2 (7). For 5 both corresponding pyrazolines were obtained in 83 % yields, for 4 TLC monitoring showed no or only marginal reaction occurs. To quantify these findings, a time resolved ¹HNMR spectroscopy study was performed. It was found that 4 reacts to a certain extent with the 6 and 7, but 5 reacts much more readily. DFT calculations underpinned these findings, showing that 5 reacts up to 6 million times faster than 4. The photo-click and the DAinv reaction were applied in MGE using Ac₄ManNCp (8), Ac₄ManNCyoc (9) and Ac₄ManNAcryl (10). For the photoclick reaction nice membrane staining was obtained for 8 and 10, whereas 9 was not labelled, for the DAinv reaction membrane staining was obtained for 8 and 9, but not for 10. The orthogonality between Ac₄ManNCyoc (9) and Ac₄ManNAcryl (10) is therefore proven.

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