Synthesis method of azepine anthraquinone

Abstract

The invention relates to a synthesis method of azepine anthraquinone. The azepine anthraquinone is obtained by carrying out intramolecular 6-endo-dig cycloisomerisation reaction shown as in formula (1) on N-propargyl quinine with a 1,5-eneyne structure under the action of a metal catalyst, and purifying, wherein the intramolecular 6-endo-dig cycloisomerisation reaction is homogeneous phase metal catalytic reaction, the metal catalyst is gold salt, platinum salt or univalent gold complex; and the use level of the metal catalyst is 0.01-0.5 equivalent weight of the N--propargyl quinine. The gold slat is auri chloridum (AuCl3) or aurous chloride (AuCl); the platinum salt is platinum tetrachloride, platinum bichloride or potassium chloroplatinate; and the univalent gold complex is PPh3AuOTf, PPh3AuSbF6, PPh3AuNTf2 or LAuNTf2, wherein L is nitrogen heterocyclic ring carbene ligand. The invention realizes the synthesis of the azepine anthraquinone by utilizing metal catalytic intramoleculareneyne cyclization reaction, and has the advantages of simple and easy-accessible raw materials and moderate reaction conditions.

Description

technical field [0001] The invention relates to a synthesis method of azaanthraquinone. Background technique [0002] Azaanthraquinone is the core structure of natural alkaloids with important biological activities. The usual structures include benzo[g]quinoline-5,10-dione, pyrido[3,2-g]quinoline-5 , 10-diketones, etc. or their derivatives, among which the simplest azaanthraquinone alkaloid is Cleistopholine. Cleistopholine derivatives with hydroxyl and methoxy substituents on some benzene rings (the specific structure is shown in A below, when R 1 =R 2 =R 3 When =H, A is Cleistopholine; Cleistopholine derivatives include the following cases: R 1 =R 2 = H, R 3 =OMe;R 1 = H, R 2 =R 3 =OMe;R 1 =OH, R 2 =OMe, R 3 = H; R 1 =OH, R 2 =R 3 =OMe) have been found one after another, and the above-mentioned derivatives all have obvious antibacterial activity and cytotoxicity (M.H.Chaves, L.de A.Santo, J.H.G.Lago, N.F.Roque, J.Nat.Prod.2001, 64, 240 .). [0003] [0...

AI Technical Summary

Problems solved by technology

There are limitations in the synthesis of azaanthraquinone by the Hetero-Diels-Alder cycloaddition method: (1) after the cycloaddition of diene body and quinone, the aromatization reaction of removing dimethylamine is obviously affected by the structure of the substrate (when R When it is an aryl group, it is necessary to use a strong oxidant manganese dioxide to carry out dehydroaromatization), the reaction conditions are harsh, and what is worse is that the aromatization reaction will release an equimolar amount of dimethylamine, and dimethylamine will interact with the parent Diene undergoes oxidation-amination side reaction

(2) When the molecular structure of the dienophile quinone is asymmetric, it is easy to generate two isomers, which directly leads to a decrease in the yield of the target product and difficulty in separation (For a review: F.Pautet, P.Nebois, Z.Bouaziz , H. Fillion, Heterocycles, 2001, 54, 1095.)

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