Patent ID: 8420807

Claim:
A method for the preparation of the compound of formula I or a pharmaceutically acceptable salt thereof comprising: reacting dibenzo[b,f][1,4]thiazepin-11-ylamine of formula III or its acid addition salt, wherein the acid addition salt is formed with an acid selected from the group consisting of acetic, fumaric, maleic, oxalic, sulfuric, phosphoric, hydrochloric, hydrobromic and nitric acid, with 1-[2-(hydroxyethoxy)-ethyl]piperazine of formula IV or its acid addition salt and wherein the compound of formula III and the compound of formula IV are not both acid addition salts and wherein an acid is added to the reaction mixture of the compound of formula III and the compound of formula IV if both the compound of formula III and the compound of formula IV are free bases; optionally liberating the salt of the compound of formula I with a base: optionally further reacting a compound of formula I with a pharmaceutically acceptable acid to produce a pharmaceutically acceptable salt; and isolating the compound of formula I or a salt thereof.