Study On Synthesis Of Heliotropine And Helional

As an important member of spices family. Heliotropine and helional are widely used in spice processing, pharmaceutical and pesticide preparation and other industries. The conventional methods based on using plant extracting safrole as raw material to synthesize heliotropine are achieved by isomerization and oxidation reaction. However, these methods suffer the drawbacks of long procedure, more materials, high cost, serious environmental pollution, and the resources of safrole are depleting. Helional is synthesized by heliotropine including condensation reaction and reduction reaction, which has higher added value, but the technology to product helional is mainly controlled by the foreign companies. In order to change this situation, based on the existing literature reports a new method by chemical total synthesis of heliotropine and helional is reported in this paper. In this method, catechol was used as the raw material, and the heliotropine was reached by cyclization reaction, condensation reaction and oxidative decarboxylation reaction. Then the heliotropine was used as the raw material, the helional was achieved by condensation and catalytic hydrogenation reaction. This dissertation is divided into three parts.First of all, as phase transfer catalyst, the influence of PEG-400, CTAC and TBAB was compared by the synthesized reaction of 1,3-benzodixoxole. Accordingly, the reaction conditions were optimized and the structure was also characterized. It was shown that the yield reached 74% with PEG-440; and the yield was up to 81% with CTAB; to our surprise, the yield was high to 95% when we use TBAB as phase transfer catalyst.Secongdly. the heliotropine was synthesized by 1,3-benzodixoxole and glyoxylic, including condensation reaction and oxidative decarboxylation reaction.The reaction conditions were correspondingly optimized, while the structure was characterized. Using the method reported in the literature. it was found that the yield was 94% in the stage of condensation reaction. With the new method of peroxid, the yield of heliotropine was 93% and high performance liquid chromatography showed 99% purity. Using the method of improving the air catalytic oxidation reported by references, the yield could reach 95% at the stage of oxidative decarboxylation.Finally, the helional was synthesized by heliotropine using condensation reaction and oxidative reduction reaction. Then the reaction conditions were optimized and the structure was approximately characterized. The results showed that the yield of 2-methyl-3-(3.4-methylenedioxyphenyl)acraldehyde was 81% with new catalyst in the stage of condensation reaction, slightly higher than that reported in the literature, and its purity reached 99% showed on high performance liquid chromatography. For good selectivity and side effects significantly reduced, the yield of helional was 82% with Pd/C as Gatalyst in catalytic hydrogenation stage while its purity reached 98%.The synthesis of heliotropine and helional were searched with new methods of total synthesis. Meanwhile, the optimized reaction conditions were received with this method. Furthermore, the foundation for further industrialization would be laid in this work.