Valsartan manufacturing process.

A process for the manufacture of the compound of formula (I) (See formula) or a salt thereof, which comprises (a) reacting a compound of formula (II a) (See formula) or a salt thereof, wherein R1 it is hydrogen or a tetrazole protecting group, with a compound of the formula or a salt thereof, wherein R2 represents hydrogen or a carboxy protecting group, under the conditions of a reductive amination; and (b) acylating a resulting compound of formula (II c) (See formula) or a salt thereof with a compound of formula (II d) (See formula) wherein R 3 is an activation group; and, (c) if R1 and / or R2 are different from hydrogen, the protecting groups are removed in a resulting compound of formula (II e) (See formula) or a salt thereof; and (d) isolating a resulting compound of formula (I) or a salt thereof; and, if desired, convert a resulting free acid of formula (I) into a salt thereof or convert a resulting salt of a compound of formula (I) into the free acid of formula (I) or convert a resulting salt of a compound of formula (I) in a different salt.