1) The reaction of N1-(4-chlorobenzoyl)-N1-(4-methoxyphenyl)hydrazine (I) [the starting material for the synthesis of indomethacin], with d,l-(2-carboxyethyl-2-phenyl)-4-oxopentanoate (II) under the conditions of Fischer indole synthesis by means of 100% phosphoric acid in toluene at 100 C. d,l-(2-Carboxyethyl-2-phenyl)-4-oxopentanoate (II) is obtained hy treatment of d,l-tropic acid with levulinic acid chloride.
2) The reaction of indomethacin (III) with thionyl chloride in hot toluene gives the corresponding acyl chloride (IV), which is then condensed with tropic acid (V) in refluxing toluene containing pyridine to afford title compound.
3) The treatment of indomethacin (III) with 1,1'-carbonyldiimidazole (A) at room temperature in dichloromethane affords the imidazolide (IVa), which is reacted with tropic acid (V) under the same mild conditions to afford title compound.
2) By condensation of 1-(3-chloro 2 hydroxypropyl)-2-nitroimidazole (III) with piperidine (IV) in refluxing methanol.
3) By condensation of 1-(2,3-epoxypropyl)-2 nitroimidazole (V) with (IV) in refluxing ethanol.