Synthesis Of Anthraquinone Derivatives And Pyrido [3,4-b] Indole Derivatives

Terpenoids are widely used in the fields of pharmaceuticals,perfumes and dyes,and have broad prospects in the field of organic synthesis.This paper studies the synthesis of two classes of anthraquinone derivatives with potential applications in the field of drug synthesis.First,a series of novel indoledione derivatives were synthesized by the addition-elimination reaction of 3-benzylidene-indol-2-one compounds with nitroalkanes.In addition,a simple synthesis of a pyrido[3,4-b]indole derivative(?-carboline derivative)was studied.First,a method for the simple synthesis of novel anthraquinone derivatives was developed.At room temperature,the 3-benzylidene-inden-2-one derivative and the nitroalkane are catalyzed by a weak base to undergo 1,4-conjugate addition,followed by denitration to obtain a series of novel indoledione derivatives 3a-i(yield 66-98%)and 5a-b(yield 72-74%).This type of compound has been characterized by HRMS,¹H NMR,¹³C NMR,IR spectroscopy,and the structure of the representative compound 3a was confirmed by X-ray single crystal diffraction.The reaction has good high-efficiency regioselectivity(determined by ¹H NMR)and the product(3a-i)has Z/E isomers>3:1.Secondly,a new method for indirectly increasing the yield of?-carboline derivatives was developed.Under the action of p-toluenesulfonic acid(Ts OH),L-tryptophan was completely converted to 1-substituted-tetrahydro-?-carboline in 5minutes under different reaction conditions,and the yield was as high as 95%.Protonic acid plays a key role in the reaction of L-tryptophan with aliphatic aldehydes or aromatic aldehydes.1-Substituted-tetrahydro-?-carboline is an important synthetic intermediate for the synthesis of?-carboline derivative.The1-Substituted-tetrahydro-?-carboline derivative is oxidized by Mn O₂ or acidic K₂Cr₂O₇ in a weakly acidic solution,and the corresponding 1-substituted-?-carboline derivative is obtained under different reaction conditions.The structures of the?-carboline derivatives 8a-i were characterized by ¹³C NMR and ¹H NMR.