The invention relates to a process for preparing 5-(&agr-haloacetyl)-8-substituted oxy-(1H)-quinolin-2-ones. The process involves (i) reacting (a) 8-hydroxy-(1H)-quinolin-2-one with an acylating agent and a Lewis acid to form 5-acetyl-8-hydroxy-(1H)-quinolin-2-one or (b) 8-hydroxy-(lH)-quinolin-2-one with an acylating agent to form 8-acetoxy-(lH)-quinolin-2-one, and treating, in-situ, the 8-acetoxy-(1H)-quinolin-2-one with a Lewis acid to form 5-acetyl-8-hydroxy-(1H)-quinolin-2-one or (c) 8-acetoxy-(1H)-quinolin-2-one with a Lewis acid to form 5-acetyl-8-hydroxy-(lH)-quinolin-2-one (ii) reacting the 5-acetyl-8-hydroxy-(1H)-quinolin-2-one prepared in Step (i) with a compound having the Formula RL in the presence of a base and a solvent to form 5-acetyl-8-substituted oxy-(1H)-quinolin-2-one, wherein R is a protecting group and L is a leaving group and (iii) reacting the 5-acetyl-8-substituted oxy-(1H)-quinolin-2-one with a halogenating agent in the presence of a solvent to form a 5-(&agr-haloacetyl)-8-substituted oxy-(1H)-quinolin-2-one.
