A simple aryl arsinous acid (ArAs(CH3)OH) was prepared by ortho mercuration of p-cresol followed by Pd-catalyzed reaction with methylarsenic dibromide, purification as the mercaptoethanol adduct, and deprotection using a silver salt. Isothermal titration calorimetry experiments showed reaction with mercaptoethanol with an association constant of 6 × 104 M−1. Rapid exchange of thiols at the arsenic atom was demonstrated by 1H-NMR.
