Process for the preparation of a Compound of formula I in the form of a single stereoisomer in crystalline form, comprising deprotecting the amine group in a Compound of formula IIa or in a mixture of a compound of formula IIa With a compound of formula IIb and isolating a Compound of formula I from the reaction mixture； Compounds and salts of Compounds of formula I in crystalline form； pharmaceutical compositions comprising such salts； processes for the preparation of intermediates and intermediates in a process for the preparation of a Compound of formula I.
