[Br:1][C:2]1[C:10]2[S:9][C:8](C(O)=O)=[CH:7][C:6]=2[CH:5]=[CH:4][CH:3]=1.C([N:17](CC)C(C)C)(C)C.P(N=[N+]=[N-])(=O)(OC1C=CC=CC=1)OC1C=CC=CC=1.C(O)(=O)C>CN(C=O)C>[Br:1][C:2]1[C:10]2[S:9][C:8]([NH2:17])=[CH:7][C:6]=2[CH:5]=[CH:4][CH:3]=1
156 mg (0.61 mmol) of 7-bromo-1-benzothiophene-2-carboxylic acid are mixed with 156.8 mg (1.21 mmol) of N,N-diisopropylethylamine in 4.0 ml of DMF. At 0° C., 183.7 mg (0.67 mmol) of diphenyl phosphorazidate are added. The reaction mixture is left to stand at 8° C. overnight and then stirred into ice-water. It is neutralized with acetic acid, and the resulting precipitate is filtered off with suction and carefully dried at 40° C. The solid is then suspended in xylene and heated under reflux for 1 h. The solvent is removed under reduced pressure, and the residue is put in water and heated for 3 h. The aqueous phase is extracted several times with ethyl acetate. The organic phase is dried over sodium sulfate and then the solvent is removed under reduced pressure. 128 mg of the title compound are isolated in a purity which is suitable for further reactions. The amine is reacted further without further purification.
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