Synthesis on the New Aroma Chemicals of Derivatives from (+) -Limonene

Abstract

(+) -2- (4-methyl-3-cyclohexenyl) propionaldehyde (2) as a component of bulgarian rose oil and (+) -2- (4-methyl-3-cyclohexenyl) allyl alcohol (3) were obtained by the oxidation of (+) -limonene (1) with lead tetraacetate. Using (2) and (3), new aromatic chemicals were synthesized.
The reaction of (2), (+) -2- (4-methyl-3-cyclohexenyl) acrylaldehyde (5) with 1, 1-dimethyl-hydrazine gave (+) -2- (4-methyl-3-cyclohexenyl) propiononitrile (6a) and (+) -2- (4-methyl-3-cyclohexenyl) acrylonitrile (6b), respectively, with lds of 7275%. Acetals (9 a), (9 b), (9 c) and (9 d) were also obtained from (2) or (5) and trimethyl orthoformate or triethyl orthoformate.
α, β-Unsaturated carboxylic acid (10) was synthesized via the condensation of aldehyde (5) with malonic acid. Alcohol (11) and esters (12 a), (12 b) (carbon numbers are C10C15) were synthesized from aldehyde (5) with C2C3 alcohols, and reduction with lithium aluminum hydride, Thesecompounds were evaluated on the basis of their odor : (6 a), (10), (12 a) emitted an odor that would qualify them for use as flavor materials.