Chemical Properties
2-Methyl-3-(3,4-methylenedioxyphenyl)propanal is a colorless to slightly yellow liquid, d
204 1.159–1.167,
n
20D 1.531–1.536, with green, floral odor with top notes of ozone and newmown
hay. It can be prepared either by condensation of heliotropin with propanal and subsequent partial hydrogenation of
the intermediately formed unsaturated aldehyde or by Lewis catalyzed reaction
of 1,2-methylenedioxybenzene with methacrolein diacetate followed by
saponification of the corresponding enol acetate .
The title compound can be used in perfumes for toiletries, for example, shaving
creams and detergents.
Synthesis
Piperonylpropionaldehyde 100g, methanol 100g, propionaldehyde 40g, potassium hydroxide 3g, reaction temperature 40, reaction time 1.5h, the yield was 71.4%. In the second step, Piperonyl propionaldehyde was hydrogenated to synthesize neojasminal, and the optimal reaction conditions were determined by one-way method as follows: 100g of Piperonyl propionaldehyde, 100g of methanol, 5g of 5% palladium-carbon catalyst, adiabatic pressure of 300KPa in hydrogenation kettle, reaction temperature of 40, reaction time of 3h, and the yield was 93.1%. The total yield of the two steps was 66.5%. The structural products of the two-step reaction were characterized. Then the one-pot synthesis of neojasmonic aldehyde was attempted, i.e., the synthesis and hydrogenation were performed in a single hydrogenation kettle. The optimum reaction conditions were explored by orthogonal method as follows: 100g of jasmonal, 100g of methanol, 40g of propionaldehyde, 5g of 5% palladium-carbon catalyst, 3g of potassium hydroxide, adiabatic pressure of 300KPa in the hydrogenation kettle, reaction temperature of 40, reaction time of 3h, and the yield of 64.8%.
