Method for preparing benzofuran derivative

1. A method for preparing a benzofuran derivative represented by formula IV, wherein a compound represented by formula IV is prepared by reacting of a compound represented by formula VI with a compound represented by formula V,

wherein X and Y are each independently selected from fluorine, chlorine, bromine, iodine, —OS(O) 2 alkyl and —OS(O) 2 aryl, preferably iodine and bromine;

R 1 , R 2 , R 3 are each identical or different, and are each independently selected from the group consisting of hydrogen atom, halogen, alkyl, haloalkyl, alkoxy, haloalkoxy, amino, nitro, hydroxyl, cyano, cycloalkyl, heterocyclyl, aryl, heteroaryl, —OR 4 , —C(O)R 4 , —C(O)OR 4 , —OS(O) 2 alkyl, and —OS(O) 2 aryl, —S(O) m R 4 , —S(O) m NR 5 R 6 and —(CH 2 )xR a , wherein alkyl, haloalkyl, heterocyclyl, aryl and heteroaryl are each independently and optionally substituted by one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxyl, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl;

E is selected from the group consisting of hydrogen atom, halogen, alkyl, haloalkyl, alkoxy, haloalkoxy, nitro, cyano, cycloalkyl, heterocyclyl, aryl, heteroaryl, —OR 4 , —C(O)R 4 , —C(O)OR 4 , —OS(O) 2 alkyl, and —OS(O) 2 aryl, —S(O) m R 4 , —S(O) m NR 5 R 6 and —(CH 2 )xR a , wherein the alkyl, haloalkyl, heterocyclyl, aryl and heteroaryl are each independently and optionally substituted by any one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxyl, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl;

R a is selected from the group consisting of halogen, cycloalkyl, heterocyclyl and —NR 5 R 6 , wherein the cycloalkyl and heterocyclyl are independently and optionally substituted by one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxyl, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl;

R 4 is selected from the group consisting of hydrogen atom, alkyl, haloalkyl, alkoxy, hydroxyalkyl, hydroxyl, amino, cycloalkyl, heterocyclyl, aryl and heteroaryl;

R 5 and R 6 are each identical or different, and are each independently selected from the group consisting of hydrogen atom, alkyl, alkoxy, hydroxyalkyl, hydroxyl, amino, carboxylate, cycloalkyl, heterocyclyl, aryl and heteroaryl, wherein the alkyl, amino, cycloalkyl, heterocyclyl, aryl and heteroaryl are each independently and optionally substituted by one or more substituents selected from the group consisting of alkyl, halogen, hydroxyl, amino, carboxylate, nitro, cyano, alkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl;

M is selected from carboxyl, hydrogen and silicyl, preferably hydrogen;

m is 0, 1 or 2;

x is 0, 1, 2 or 3.

2. The method according to claim 1 , wherein the reacting of the compound represented by formula VI with the compound represented by formula V is performed under the action of at least one metal catalyst and/or at least one alkaline substance, wherein the metal catalyst is selected from a metal palladium catalyst, a metal zinc catalyst, a metal copper catalyst and a metal nickel catalyst, preferably a metal copper catalyst, and more preferably a monovalent metal copper catalyst, wherein the alkaline substance is selected from the group consisting of KHCO 3 , NaHCO 3 , Na 2 CO 3 , Ba(OH) 2 , K 3 PO 4 , Cs 2 CO 3 , K 2 CO 3 , KF, CsF, KCN, NaCN, NaOH, KOH, Et 3 N, DIPEA, DABCO, NaOMe, NaOEt, t BuOK, t BuONa, NaH, DBU, TMG, LHMDS, NaHMDS, n-BuLi, sodium tert-pentoxide, diethylamine and dicyclohexylamine, preferably t BuOK and t BuONa.

3. The method according to claim 2 , wherein the reaction solvent is one or more selected from the group consisting of dimethylformamide, 1-methyl-2-pyrrolidone, tetrahydrofuran, methyltetrahydrofuran, dioxane, toluene, xylene, dimethylsulfoxide, diethyl ether, isopropyl ether, methyl tert-butyl ether, acetonitrile, propionitrile, isopropanol, propanol, ethanol, methanol and water.

4. The method according to claim 2 , wherein the reaction is carried out under the protection of an inert gas selected from nitrogen, argon and helium, preferably argon.

5. The method according to claim 1 which comprises the step of a compound represented by formula IVa is prepared by reacting of a compound represented by formula VIa with a compound represented by formula Va,

6. The method for preparing the compound represented by formula IVa according to claim 5 , which further comprises preparing the compound represented by formula VIa by using a compound represented by formula VIIa under the action of a brominating reagent and at least one acid,

wherein the brominating reagent is selected from the group consisting of HBr, Br 2 , NBS, DBDMH, HOBr, AcOBr, CF 3 COOBr, NH 4 Br, TBBDA, PBBS and tribromoisocyanurate, preferably NBS or DBDMH, wherein the acid is selected from the group consisting of AlCl 3 , SbCl 5 , FeCl 3 , FeBr 3 , SnCl 4 , TiCl 4 , ZnCl 2 , BF 3 , acetic acid, sulfuric acid, hydrochloric acid and trifluoroacetic acid, preferably sulfuric acid or trifluoroacetic acid.