| Autor: |
Fang Y; Brown Laboratories , Department of Chemistry and Biochemistry , University of Delaware , Newark , DE 19716 , USA . Email: jmfox@udel.edu., Zhang H; Brown Laboratories , Department of Chemistry and Biochemistry , University of Delaware , Newark , DE 19716 , USA . Email: jmfox@udel.edu., Huang Z; Pfizer Worldwide Research and Development , Cambridge , Massachusetts 02139 , USA., Scinto SL; Brown Laboratories , Department of Chemistry and Biochemistry , University of Delaware , Newark , DE 19716 , USA . Email: jmfox@udel.edu., Yang JC; Pfizer Worldwide Research and Development , Cambridge , Massachusetts 02139 , USA., Am Ende CW; Pfizer Worldwide Research and Development , Groton , Connecticut 06340 , USA., Dmitrenko O; Brown Laboratories , Department of Chemistry and Biochemistry , University of Delaware , Newark , DE 19716 , USA . Email: jmfox@udel.edu., Johnson DS; Pfizer Worldwide Research and Development , Cambridge , Massachusetts 02139 , USA., Fox JM; Brown Laboratories , Department of Chemistry and Biochemistry , University of Delaware , Newark , DE 19716 , USA . Email: jmfox@udel.edu. |
| Abstrakt: |
A photochemical synthesis of AgNO 3 complexes of trans -cycloheptene (TCH) and trans -1-sila-4-cycloheptene (Si-TCH) derivatives is described. A low temperature flow photoreactor was designed to enable the synthesis of carbocyclic TCH derivatives due to their thermal sensitivity in the absence of metal coordination. Unlike the free carbocycles, TCH·AgNO 3 complexes can be handled at rt and stored for weeks in the freezer (-18 °C). Si-TCH·AgNO 3 complexes are especially robust, and are bench stable for days at rt, and for months in the freezer. X-ray crystallography was used to characterize a Si-TCH·AgNO 3 complex for the first time. With decomplexation of AgNO 3 in situ , metal-free TCO and Si-TCH derivatives can engage in a range of cycloaddition reactions as well as dihydroxylation reactions. Computation was used to predict that Si-TCH would engage in bioorthogonal reactions that are more rapid than the most reactive trans -cyclooctenes. Metal-free Si-TCH derivatives were shown to display good stability in solution, and to engage in the fastest bioorthogonal reaction reported to date ( k 2 1.14 × 10 7 M -1 s -1 in 9 : 1 H 2 O : MeOH). Utility in bioorthogonal protein labeling in live cells is described, including labeling of GFP with an unnatural tetrazine-containing amino acid. The reactivity and specificity of the Si-TCH reagents with tetrazines in live mammalian cells was also evaluated using the HaloTag platform. The cell labeling experiments show that Si-TCH derivatives are best suited as probe molecules in the cellular environment. |
