Sigma-Aldrich 4-Br-(-)-psi >=95%

Air- and moisture-tolerant, 4-Br-(-)-psi was developed in the Baran lab for stereocontrolled synthesis of phosphorothioate oligonucleotides. Compared to the first generation (-)-psi Reagent (ALD00602), this reagent is more cost effective and easier to handle. The enantiomer, 4-Br-(+)-psi Reagent, is also available. The psi Reagents open access to thiophosphate-based nucleotide molecules with therapeutic promise as demonstrated by the Baran lab in the preparation of pure stereoisomers of cyclic dinucleotides (CDNs) and antisense oligonucleotides (ASOs).