Synthesis Of3-and5-substituted Indole Derivatives

Indole is a kind of nitrogen heterocyclic compound with two circles. A higher indole wassmell, but a lower indole was of perfume as chemical products. The indole derivatives werefound abundance in medical, dyestuffs, plant growth regulator and so on. Melatonin and5-hydroxytryptophan were usually prepared by the substituted5-indole derivatives. The greatmajority of5-hydroxytryptophan can be mainly obtained by extracting from griffoniasimplicifolia seeds. The demand for the medicine exceeded the supply. At present, althoughmost scientists had developed the production line of5-hydroxytryptophan and produced, theprocess of ferment was polluted easily and the low yields were still a difficult problem. Sofinding a new and efficient production route is very important.In chapter2and chapter3in this paper, novel routes for the synthesis of the5-substitutedindole derivatives such as5-bromoindole,5-hydroxytryptophan and5-methoxyindole whichwere all prepared from indoles were described, Firstly,2-sodium sulphonate was obtainedwith a pH4-solution at25℃in good yield of86.5%. Then, it was easy to synthesizeN-acetyl-2-sodium sulphonate by adding some acetic anhydride. They were prepared at70℃for2h and90℃for0.5h in yield of84.8%by the reaction of N-acetyl-2-sodium sulphonateindole with acetic anhydride. Finally,5-bromoindole was obtained by adding some bromoineto a indole solution at-5℃for1h firstly and then at120℃for20h, while pH at11in a yieldof87.6%.5-methoxyindole was synthesized by5-bromoindole with yield67%. This reactionwas happened at90℃and at the ratio1:12of5-bromoindole and sodium methoxide.5-HTwas synthesized by the hydrolysis of5-bromoindole with20%potassium hydroxide solution.And the yield was up to81.2%.In chapter4in the paper, a new synthesis route for5-hydroxytryptophan was developed,using5-Bromoindole as a starting material. The synthesis involves substitution in the third ofthe indole circle then hydrolysis with the total yield of42.3%.The authors had designed thenew route to reduce the step and raise productivity by drawing inspiration from the synthesisof tryptophan.5-bromoindole can be easily obtained with the simple route and the reactioncondition which is significant for industrial production.