Sodium Hydroxide → Sildenafil

Participants

Reaction Conditions

Reaction Steps

In a 0.25 L reactor equipped with mechanical stirrer and thermometer, 100 ml of acetone was added. The reactor was maintained at room temperature (22° C.). 5.35 g of N-methyl piperazine (1.1 equivalents) followed by 4.16 g of NaOH solution (47%, 1 equivalent) were added. 20 g of 1-[[3-(4,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)-4-ethoxyphenyl] sulfonyl chloride was added portion-wise (5 g each). The reaction mixture was kept at room temperature with mixing for 1 hour. The reaction mixture was kept at 5° C. for 2 hours. During that period, sildenafil base precipitated. After filtration, the cake was washed with water (50 ml). 29.24 g wet sildenafil base was obtained.

Provenance & Evidence