Preparation
The dextro-form is obtained practically pure by the fractional distillation of caraway oil; the levo-form from the oils containing it, by first forming its addition compound with hydrogen sulfide, decomposing this by potassium hydroxide in ethanol, and distilling the product in a current of steam. It may be synthetically prepared from limonene nitrosochloride, alcoholic converting this compound into 1-carvoxime, which on boiling with dilute sulfuric acid yields l-carvone. The major use of d-limonene is as a precursor to carvone. The large scale availability of orange rinds, a byproduct in the production of orange juice, has made limonene cheaply available, and synthetic carvone correspondingly inexpensively prepared.
The biosynthesis of carvone is by oxidation of limonene.
Read more about this topic: Carvone
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