To 20% solution of phosgene in toluene, agitated and cooled to 0°C, are
added over 30 min a solution of 1-p-fluoro-benzoyl-1-hydroxy-3-N-[N'-(2-
methoxyphenyl)]piperazinopropane and triethylamine in anhydrous
chloroform. It is agitated at ambient temperature for 5 h, cooled to 0°C and
the solution saturated with gaseous ammonia. The solution is agitated at
ambient temperature for 3 h, filtered and the filtrate dried under reduced
pressure, 4-ρ-fluorophenyl-5-β-(4-o-methoxyphenylpiperazino)ethyl-4-
oxazolin-2-one, melting point 154°C (by alcohol) was obtained.
