Methanol → Avosentan

Participants

Reaction Steps

To a solution of 6.9 g sodium in MeOH (300 ml) were added 14.52 g of 5-methyl-pyridine-2-sulfonic acid [6-chloro-5-(2-methoxy-phenoxy)-2-pyridin-4-yl-pyrimidin-4-yl]-amide at RT and the mixture was refluxed for 5 days until completion of the reaction according to TLC analysis. The reaction mixture was concentrated in vacuo to half its volume upon which the crude reaction product precipitated as a sodium salt. It was filtered off by suction and dried in a high vacuum. The solid was dissolved in water, which was then made acidic by addition of acetic acid. The precipitating free sulfonamide was extracted into Me2Cl2. The organic layer was dried over Mg2SO4, concentrated on a rotary evaporator, and the crystalline solid that had formed was filtered off. It was then dried in a high vacuum for 12 h at 120° C. to give the desired 5-methyl-pyridine-2-sulfonic acid [6-methoxy-5-(2-methoxy-phenoxy)-2-pyridin-4-yl-pyrimidin-4-yl]-amide as white crystals. Melting point 225-226° C. ISN mass spectrum, m/e 478.2 (M-1 calculated for C23H21N5O5S1: 478).

Provenance & Evidence