A peep into p-menth-1-ene chemistry

Backed by a rich and chequered chemistry, p-meth-1-ene enjoys status next to that of the 3-isomer in terpene chemistiy. Assignment of the structure to p-meth-1-ene is essentially based on its oxidation with KMnO4 to acetic acid and β-isopropylglutaric acid; this is further supported by spectral data. Though apparently not existing naturally, p-menth-1-ene is synthetically available in (+), (–) and (±)-forms.

The earliest approaches to p-menth-1-ene are centered on carvomenthol. From this alcohol, p-menth-1-ene is liberated by heating with KHSO4, boric anhydride, or anhydrous CuSO4. Or by reaction with HBr or HCl, it is converted to 2-bromo- (or chloro-)-p-menthane, which upon digestion with quinoline or alcoholic KOH11 affords the title compound.

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