6-Amino[14]aneS₄: A New Amine-Functionalised Crown Chalcogenide

We report the first synthesis of 6-amino-1,4,8,11-tetrathiacyclotetradecane (6-amino[14]aneS₄, 1) which is, to our knowledge, the first example of a crown chalcogenide incorporating a primary amine on the carbon backbone. Both routes discussed herein have as their key step functional group conversion from hydroxyl to phthalimide-protected amine using the Mitsunobu reaction. The first route entails Mitsunobu reaction of 6-hydroxy[14]aneS₄ (2) with phthalimide and results in the formation of a mixture of products whose distribution implies the common intermediacy of an episulfonium ion (EPSI). In the second pathway, 1,3-dichloro-2-propanol is converted 2-amino-1,3-dichloropropane N-phthalimide (3) from which 6-amino[14]aneS₄ N-phthalimide (4) can be obtained by cyclisation with 1, 4, 8, 11 N-tetrathiaundecane under high dilution conditions in DMF in the presence of Cs₂CO₃. Deprotection of 4 with NH₂NH₂ hydrate yields the target molecule, 1.

crown thioether - Mitsunobu - episulfonium ion - chalcogenide