2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine

Li Xiao, Alexander Pöthig, Lukas Hintermann

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Abstract The chemistry of 4,6-dialkyl-2-amino-1,3,5-triazines with bulky alkyl substituents was investigated and their use as building blocks for preparing chiral thiourea organocatalysts explored. Reaction of ammonia with 4,6-di-tert-butyl-2-chloro-1,3,5-triazine gave 4,6-di-tert-butyl-1,3,5-triazin-2-amine which formed extended hydrogen-bond networks in the solid state according to X-ray crystallography. Selected heterocyclic amines were converted to isothiocyanates, and the latter reacted with (S,S)-2-(dimethylamino)cyclohexylamine to give enantiopure 1-hetaryl-3-[2-(dimethylamino)cyclohexyl]thioureas, with hetaryl representing either 4,6-dimethyl-1,3-diazin-2-yl, 4,6-diisopropyl-1,3,5-triazin-2-yl, or 4,6-di-tert-butyl-1,3,5-triazin-2-yl groups. These compounds are structural analogs of Takemotos's chiral thiourea organocatalysts (1-[3,5-bis(trifluoromethyl)phenyl]-3-[(1S,2S)-2-(dimethylamino)cyclohexyl]thiourea) with an aza-aryl instead of the 3,5-bis(trifluoromethyl)phenyl group. They feature a strong intramolecular N-H to N-1 hydrogen bond, as shown by X-ray crystallography of 1-(4,6-di-tert-butyl-1,3,5-triazin-2-yl)-3-[2-(dimethylamino)cyclohexyl]thiourea in the solid state and by 1H NMR spectroscopy of all derivatives in CDCl3 solution, which prevents them from acting as bifunctional organocatalyst. In the reaction of 4,6-di-tert-butyl-2-chloro-1,3,5-triazine with ammonia, 4,6-di-tert-butyl-2-ethoxy-1,3,5-triazine was identified as side-product displaying a mildly sweet, floral odor that is unusual for a 1,3,5-triazine. Analogs (>35) of 4,6-di-tert-butyl-2-ethoxy-1,3,5-triazine were prepared to define the important structural factors of the olfactophore.

Original languageEnglish
Article number1515
Pages (from-to)1529-1539
Number of pages11
JournalMonatshefte für Chemie
Issue number9
StatePublished - 7 Sep 2015


  • Amines
  • Heterocycles
  • Hydrogen bonds
  • Odoriferous substances
  • Triazines


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