THE OXIDATIVE ADDITION-REACTION BETWEEN COMPOUNDS OF RESORUFIN (7-HYDROXY-3H-PHENOXAZIN-3-ONE) AND 2-MERCAPTOETHANOL

2-Mercaptoethanol reacts with the methanesulphonate, the dimethylcarba mate, and the ethyl ether of resorufin (7-hydroxy-3H-phenoxazin-3-one) at 25 degrees C and pH 7.4 to give colored products with maximal abso rbances at 433, 442, and 481 nm, respectively. NMR spectra of the prod ucts show that the hydrogen atom on C-2 has been specifically replaced by the -SCH2CH2OH group, it is concluded that the thiol adds to the q uinonimine ring and that the first-formed product then undergoes spont aneous oxidation to reform the resorufin structure. The implications o f these studies toward biochemical work with resorufin derivatives is discussed. (C) 1998 Academic Press