Methods for preparation of losartan and losartan potassium.

摘要

Process for preparing losartan and pharmaceutically acceptable salts, comprising a) contacting a compound of formula (II): wherein each R1, R2, R1¿, R2¿, R1¿¿ and is R2¿¿ independently selected from the group consisting of hydrogen; halogen; alkyl, which may be optionally substituted with one or more of halogen, hydroxy or lower alkoxy, alkenyl, which may be optionally substituted with one or more halogen, hydroxy or lower alkoxy; nitro; cyano; vinyl; styryl; a group of COR3 asked: would, -CO2R3, -OR3, -SR3, -SO2R3, -NR3R4, -NCO2R3, or -OCO2R3 where R3 and R4 are atoms and radicals independently selected from the group consisting of hydrogen, lower alkyl, aralkyl, aryl and heteroaryl; or where R1 and R2 or R¿1 and R¿2 or R¿1 and R¿2 occupy two adjacent positions they may join to form an optionally substituted carbocyclic or heterocyclic ring and an acid in a diluent comprising a liquid ketone for a period of time sufficient to convert the compound substantially losartan, b) basifying the diluent, c) evaporating liquid ketone, leaving a residue, d) precipitating a triarylmethyl alcohol of formula (III): wherein R1, R2, R1¿, R2¿, R1¿¿ and R2¿¿ are as defined above, from the residue, e) separating the precipitated triarylmethyl alcohol from the residue, f) acidifying the residue, g) precipitating losartan from the residue, and h) separating losartan from the residue.