Doxazosin → Doxazosin Mesylate

Participants

Reaction Steps

17.7 g of anhydrous methanesulfonic acid were added to a stirred mixture of 79.0 g of doxazosin and 800 ml of methanol in a 2 1 three-necked round-bottomed flask. During this, the internal temperature rose to 30° C., and a solution formed. After the addition of the methanesulfonic acid was complete, the mixture was stirred for a further 5 h. The resulting precipitate was then filtered off with suction and washed 3× with 50 ml of methanol each time. 141.8 g of moist doxazosin mesylate (modification D) were obtained. This corresponds to 89.2 g of dry substance and a yield of 93.1%.

Provenance & Evidence