Pharmaceutical drug candidates and methods for preparation thereof

A method of preparation of a purity-enhanced pharmaceutical drug candidate comprising:

• opening a sultone ring with a nucleophile, such that a purity-enhanced sulfonate derivatized pharmaceutical drug candidate is produced,
• wherein the sulfonate derivatized pharmaceutical drug candidate is selected from the group consisting of 1,3-propanedisulfonic acid disodium salt, 1,3-propanedisulfonic acid, 1,4-butanedisulfonic acid disodium salt, 3-amino-1-propanesulfonic acid, 3-amino-1-propanesulfonic acid, sodium salt, 3-(dimethylamino)-1-propanesulfonic acid, 3-(1,2,3,6-tetrahydropyridinyl)-1-propanesulfonic acid, 3-(1,2,3,4-tetrahydroisoquinolinyl)-1-propanesulfonic acid, 3-(4-cyano-4-phenylpiperidin-1-yl)-1-propanesulfonic acid, 3-[4-(4-fluorophenyl)-1,2,3,6-tetrahydropyridin-1-yl]-1-propanesulfonic acid, 3-[4-(4-bromophenyl)-4-hydroxypiperidin-1-yl]-1-propanesulfonic acid, 3-[4-(4-chlorophenyl)-4-hydroxypiperidin-1-yl]-1-propanesulfonic acid, 3-(4-acetyl-4-phenylpiperidin-1-yl)-1-propanesulfonic acid, 3-[4-(4-chlorophenyl)-1,2,3,6-tetrahydropyridin-1-yl]-1-propanesulfonic acid, 3-tryptamino-1-propanesulfonic acid, 3-(1,2,3,4-tetrahydro-naphthylamino)-1-propanesulfonic acid, 3-(1-adamantylamino)-1-propanesulfonic acid, 3-(2-norbornylamino)-1-propanesulfonic acid, 3-(2-admantylamino)-1-propanesulfonic acid, 3-(4-(hydroxy-2-pentyl)amino)-1-propanesulfonic acid, 3-nonylamino-1-propanesulfonic acid, and 3-(t-butylamino)-1-propanesulfonic acid.