Title:Iodine-Mediated Aromatization of Himachalenes: Synthesis of Dehydro-7,8-arylhimachalene
Volume: 21
Issue: 12
Author(s): Isam Louchachha*, Youssef Edder, Abdelmajid Faris, Brahim Boualy, Mustapha Ait Ali and Abdallah Karim
Affiliation:
- Laboratory of Molecular Chemistry, Faculty of Sciences Semlalia, Cadi Ayyad University BP 2390, 40001 Marrakech,
Morocco
Keywords:
Sesquiterpene, dehydro-7, 8-arylhimachalene, iodine-mediated aromatization, natural products, benzocycloheptene, himachalene, cedar oil.
Abstract:
Dehydro-7,8-aryl-himachalene is a desired natural benzocycloheptene sesquiterpene
found in the essential oil of Atlas cedar (Cedrus atlantica) in minor quantities. Herein, we report a
simple and environmentally benign synthesis of this molecule via the aromatization of himachalene
mixture (the major constituent of the same oil).
The synthesis of the desired compound has been achieved by iodine/DMSO-mediated aromatization.
The synthesized product has been characterized using MS spectrometry and NMR spectroscopy data.
The treatment of the himachalene mixture with iodine led to the formation of dehydro-7,8-arylhimachalene,
along with other rearrangement products catalyzed by the hydroiodic acid formed in
situ. The use of DMSO as a co-solvent enabled the elimination of the acid formed and the regeneration
of iodine. The optimization of the reaction conditions led to the formation of the desired product
with a good yield.
The present study highlights the development of a simple and environmentally benign method for the
synthesis of a natural benzocycloheptene-based sesquiterpenoid in large quantities in order to explore
its biological and chemical properties.