New and Efficient Conversion of Benzoic Acids into Salicylic Acids via Copper Mediated Hydroxylation Process
17 September 2002 (online)
N-benzoyl-2-methylalanines 3, obtained through condensation of aroyl chlorides 1 with sodium 2-methylalaninate are ortho-hydroxylated by the new Cu(0)/O2/trimethylamine N-oxide system. Acid hydrolysis of the so-obtained salicylamides 4 provides salicylic acids 5 in excellent yield. When the substrate contains three electron-releasing groups the yields are moderate.