2-Nitro-5-thiocyanatobenzoic acid

2-Nitro-5-thiocyanatobenzoic acid (NTCB) is a highly reactive reagent that transfers its cyano group rapidly to a nucleophilic thiolate. 2-Nitro-5-thiocyanatobenzoic acid has been proposed as a reagent for converting thiol groups in proteins into their S-cyano derivatives[1][2].