Indomethacin → 1-(p-Chlorobenzoyl)-2-methyl-5-methoxy-3-indolylacetic acid-3-pyridylmethyl ester

Participants

Reaction Steps

A mixture of 3.0 g of 1-(p-chlorobenzoyl)-2-methyl-5-methoxy-3-indolylacetic acid and 3.0 g of thionyl chloride was refluxed in 70 ml of benzene for 3 hours. After cooling, the solvent was distilled off under reduced pressure to leave a residue. The residue was dissolved in 20 ml of tetrahydrofuran. This solution was added to a solution of 1.0 g of 3-pyridylmethanol in 70 ml of tetrahydrofuran under cooling. To this mixture was carefully added 0.95 g of triethylamine and stirring was continued for 2 hours at room temperature. After the reaction was complete, the solvent was removed by distillation under reduced pressure to leave a residue. After addition of water to the residue, an oily substance was obtained and extracted with chloroform. The extract was applied on a column of silica gel and the adsorbate was eluted with ether to give crystals. Recrystallization of the crystals from a mixed solvent of ethyl acetate ester and ether yielded 3.0 g of 1-(p-chlorobenzoyl)-2-methyl-5-methoxy-3-indolylacetic acid-3 -pyridylmethyl ester, melting at 116°-118° C. Analysis--Calculated for C25H21ClN2O4 : C, 66.89; H, 4.72; N, 6.24. Found: C, 67.06; H, 4.68; N, 6.11.

Provenance & Evidence