Natural<unk>  exists as one pure stereoisomer, nearly always the (1R,2S,5R) form (bottom left corner of the diagram below). The eight possible stereoisomers are: :Structures of<unk>  isomers In the natural compound, the isopropyl group is in the trans orientation to both the methyl and hydroxyl groups. Thus, it can be drawn in any of the ways shown:<unk>  chair conformation Ball-and-stick 3D model highlighting<unk> 's chair conformation The (+)- and (−)-enantiomers of<unk>  are the most stable among these based on their cyclohexane conformations. With the ring itself in a chair conformation, all three bulky groups can orient in equatorial positions. The two crystal forms for racemic<unk>  have melting points of 28 °C and 38 °C. Pure (−)-menthol has four crystal forms, of which the most stable is the α form, the familiar broad needles.
Menthol
Desmethylchlorotrianisene
Benzyl alcohol
Khat
Keldur
Chlorotrianisene
Cannabis 
Cannabis