1. Menthol
Dr.Javid Hussain
John 1

2. Chemical Properties Chemical Formula: C10H20O
IUPAC Name: (1R,2S,5R)-2-Isopropyl- 5-Methylcyclohexanol
Molar Mass: g/mol
Density: g  cm-3
Marco 2

3. Chemical Properties Boiling Point: 212 °C Melting Point: 36-38 °C
Solid at room temperature
Waxy, crystalline substance
Clear or White in color
Optically active compound
Only (-) form is found naturally
Present in peppermint oil
John 3

4. Medicinal Uses
Marco
Digestive Tract………The menthol in peppermint.. Also stimulates the production of bile
Hot cup of tea, great way to settle the stomach after a big meal. n
Used very often as a flavoring agent
Chewing gum, candy
Menthol Vapors are famous for relieving nasal, sinus and chest congestion.
Also, the steam from the same tea that you made to soothe your digestive tract, will relieve some congestion
Vicks Vaporub, Mentholatum
Antipruritic to releve itching
Topical Analgesic to relieve minor aches and pains such as muscle cramps, sprains & headaches
Icy Hot, Tiger Balm & Knee/elbow sleeves
In certain medications to treat sunburns
Cooling sensation (often associated w/ aloe)
Found in chloroform sprays for the relief of localized pain 4

5. Products Found In
In cigarettes for flavor and to reduce throat and sinus irritation caused by smoking
Ricqles contains 80% alcohol and is used to alleviate nausea, in particular motion sickness.
Achieved by pouring a few drops on a lump of sugar.
In Japan, they sell fever reducing patches that children would put on their forehead to achieve a cooling feeling.
Excellent breath freshener
Increase effectiveness by adding anise, caraway or cinnamo 5

6. Structural Isomers
John
What do + and – mean? Significance? 7

7. Naturally Occurring Isomers
The Isopropyl must always be in the trans orientation to both the methyl and hydroxyl groups.
All of these representations are correct!
Notice how all three bulky groups are in the equatorial position, making (-)Menthol and it’s enantiomer the two moststable isomers out of the eight. 8

8. Index of Hdrogen deficiency (IHD)
Molecular Formula = C10H20O
Alkane = C10H20×2+2
IHD = = 2/2 =

9. Hydrogenation Catalytic Hydrogenation cause no change in the structure
No reaction takes place
Mean molecule is saturated
Cotains no C=C

10. Bromination Cause no change in the structure No reaction takes place
Proves that menthol is Saturated
Contain no C=C

11. Nature of oxygen Formation of ester
Shows that nature of oxygen in menthol is alcoholic

12. Oxidation Give ketone called Menthone
Shows that Menthol is a secondary alcohol

13. Reduction Reduction with HI/P give P. Menthane
Most probably the Menthol will have this skeleton

14. Formation of Menthol by the reduction of Pulegone

15. On the basis of all above reaction the structure of menthol was found to be

16. Synthesis of Menthol

17. Synthesis
Marco
As is the case w/ many widely used natural products, the demand for menthol greatly exceeds the natural supply.
Manufactured as a single enantiomer (94%) on the scale of 3,000 tons per year by takasago International Corporation.
Developed by a team that is led by Ryoji Noyori.
Know if the compound is e or z in each compound 9

18. Possible Reactions From Menthol
Marco
Menthone
Has been oxidized by Chromium Trioxide
Oxidation an also be achieved by using other oxidizing agents such as Chromic acid or dichromate
Bottom Left
Oxidation has caused the ring to break open
3-Menthene
Can be easily dehydrated to achieve 3-Menthene
This H2SO4 is 2% Sulfuric Acid
CrO3 = Chromium Trioxide
CH3COOH = Acetic Acid
PCL5 = Phosphorus Pentachloride
Substitution
Which is stronger? Dil H2SO4 or H2SO4
Remember to look up what it means for a compound to undergo oxidation?!? 10

19. Stereochemistry Stereochemistry
Examination of menthol structure shows that three chiral centre are present. Thus 8 isomeric forms are possible.
2n = 23 = 8
n = number of chiral centres

20. Acknowledgments
Thanks
last 12