How is (6R)-N~6~-Propyl-4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine dihydrochloride hydrate (CAS: 908244-04-2) typically synthesized?

(6R)-N~6~-Propyl-4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine dihydrochloride hydrate can be synthesized by the reaction of propylamine with 2,6-diamino-4,5,6,7-tetrahydro-1,3-benzothiazole in the presence of a suitable solvent such as ethanol. The process involves the addition of propylamine to the amine ring of the benzothiazole derivative, followed by the addition of hydrochloric acid to form the dihydrochloride salt. The reaction is typically carried out under mild conditions, yielding a product with high selectivity and good yield.