β-Terpineols

β-Terpineol was introduced into the chemical world at the beginning of the century by contributions from Schimmel & Co. From liquid "terpineol," the chemists of Schimmel isolated, in additon to α-terpineol phenylurethane, its isomer, m.p. 85°, the hydrolysis of the latter released β-terpineol. Also by rigorous fractionation of liquid "terpineol" under reduced pressure, the optically inactive fractionation, b.p. 212-213, was separated, and upon congealing it deposited the then new isomeric terpineol, which was recrystallised in long needles from ethanol. Following this trial, others have confirmed the presence of β-terpineol in commercial terpineol. A recent GLC analysis revealed that terpineol prepared from terpin hydrate was a mixture that included β-terpineols to the extend of ≈ 18%.

Earlier researches on β-perpineol were on samples isolated from commercial terpineol. Plane formula is assigned to the alcohol based on regulated degradation epitomised in figure 1. Oxidation of the alcohol first with dilute KMnO4 and then with chromic acid gave the hydroxy-ketone plus the unsaturated ketone; these ketones were converted into p-toluic acid. Terminal unsaturation was disclosed by the formation of formaldehyde on ozonolysis. Formula (1) fulfills these findings and it is further corroborated by synthesis.

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