Abstract: The present invention relates to a process for the preparation of ticagrelor, which provides a product of high purity, in particular, with no detectable levels of Nnitrosmine impurities. The process comprises a first step of treating 2- [[(3aR,4S,6R,6aS)-6-[[5-amino-6-chloro-2-(propylthio)-4-pyrimidinyl]amino]tetrahydro-2,2-dimethyl-4H-cyclopenta-1,3-dioxol-4-yl]oxy]ethanol starting material with sodium nitrite, followed by acidic washing; in a second step, the 2-[[(3aR,4S,6R,6aS)-6-[7-chloro-5-(propylthio)-3H-1,2, 3-triazolo[4,5-d]pyrimidin-3-yl]tetrahydro-2,2-dimethyl-4H- cyclopenta-1,3-dioxol-4-yl]oxy]ethanol obtained in the previous step is coupled with trans-(1 fl,2S)-2-(3,4-difluorophenyl)cyclopropylamine, and the reaction is followed by a first washing at basic pH a second washing at acidic pH; and in an third step, the compound obtained in the previous step is deprotected by treatment with mineral acid, followed by acidic washing.

Abstract: This invention relates to a process for the preparation of pimavanserin comprising: (i) providing an acid addition salt of pimavanserin; (ii) dissolving the acid addition salt of pimavanserin in an aqueous solvent to form an aqueous solution; (iii) washing the aqueous solution obtained in step (ii) with an organic solvent; and (iv) adding a base to the washed aqueous solution to form pimavanserin. The invention also relates to a process for the preparation of an acid addition salt of pimavanserin additionally comprising step (v) of converting pimavanserin into an acid addition salt of pimavanserin. The invention also relates to pimavanserin or an acid addition salt thereof obtainable by the process, and to the use of pimavanserin hydrochloride, pimavanserin hydrogen sulfate or pimavanserin acetate for preparing pimavanserin or an acid addition salt thereof.