2'-O-Propargyl-U CE Phosphoramidite

2'-O-Propargyl-U CE Phosphoramidite is a click-handle RNA building block: 5'-O-(4,4'-dimethoxytrityl)-2'-O-(prop-2-yn-1-yl)uridine 3'-O-(2-cyanoethyl N,N-diisopropyl)phosphoramidite. It is identified by CAS 171486-62-7, molecular formula C42H49N4O9P, molecular weight 784.8, PubChem CID 102390146, and InChIKey SKUHDLBLPLSZJC-CYSIDSPMSA-N.

The 2'-O-propargyl group is a permanent 2'-O-ether that carries a terminal alkyne (C≡CH) — it is not a protecting group. That terminal alkyne is a "click" handle: oligonucleotides bearing a terminal alkyne can be labeled after synthesis by the copper-catalyzed azide-alkyne cycloaddition (CuAAC) with azide-bearing reporters. Uracil has no exocyclic amine, so no base protecting group is needed; the monomer couples through a standard 3'-phosphoramidite (3'→5' linkages) and the 5'-DMT is removed each cycle.