41340-35-6Relevant articles and documents
Directed evolution of RebH for catalyst-controlled halogenation of indole C-H bonds
Andorfer, Mary C.,Park, Hyun June,Vergara-Coll, Jaylie,Lewis, Jared C.
, p. 3720 - 3729 (2016/06/09)
RebH variants capable of chlorinating substituted indoles ortho-, meta-, and para-to the indole nitrogen were evolved by directly screening for altered selectivity on deuterium-substituted probe substrates using mass spectrometry. This systematic approach allowed for rapid accumulation of beneficial mutations using simple adaptive walks and should prove generally useful for altering and optimizing the selectivity of C-H functionalization catalysts. Analysis of the beneficial mutations showed that structure-guided selection of active site residues for targeted mutagenesis can be complicated either by activity/selectivity tradeoffs that reduce the possibility of detecting such mutations or by epistatic effects that actually eliminate the benefits of a mutation in certain contexts. As a corollary to this finding, the precise manner in which the beneficial mutations identified led to the observed changes in RebH selectivity is not clear. Docking simulations suggest that tryptamine binds to these variants as tryptophan does to native halogenases, but structural studies will be required to confirm these models and shed light on how particular mutations impact tryptamine binding. Similar directed evolution efforts on other enzymes or artificial metalloenzymes could enable a wide range of C-H functionalization reactions.
Structure-activity relationships of 2,N6,5′-substituted adenosine derivatives with potent activity at the A2B adenosine receptor
Adachi, Hayamitsu,Palaniappan, Krishnan K.,Ivanov, Andrei A.,Bergman, Nathaniel,Gao, Zhan-Guo,Jacobson, Kenneth A.
, p. 1810 - 1827 (2008/02/06)
2, N6, and 5′-substituted adenosine derivatives were synthesized via alkylation of 2-oxypurine nucleosides leading to 2-arylalkylether derivatives. 2-(3-(Indolyl)ethyloxy)adenosine 17 was examined in both binding and cAMP assays and found to be a potent agonist of the human A2BAR. Simplification, altered connectivity, and mimicking of the indole ring of 17 failed to maintain A2BAR potency. Introduction of N6-ethyl or N6-guanidino substitution, shown to favor A2BAR potency, failed to enhance potency in the 2-(3-(indolyl)- ethyloxy)adenosine series. Indole 5″- or 6″-halo substitution was favored at the A2BAR, but a 5′-N-ethylcarboxyamide did not further enhance potency. 2-(3″-(6″-Bromoindolyl)ethyloxy)adenosine 28 displayed an A2BAR EC50 value of 128 nM, that is, more potent than the parent 17 (299 nM) and similar to 5′-N- ethylcarboxamidoadenosine (140 nM). Compound 28 was a full agonist at A 2B and A2AARs and a low efficacy partial agonist at A 1 and A3ARs. Thus, we have identified and optimized 2-(2-arylethyl)oxo moieties in AR agonists that enhance A2BAR potency and selectivity.
