Radiolabeled fapi complex, and preparation method therefor and use thereof

A preparation method for a radiolabeled FAPI complex, comprising steps as follows:

• (1) dissolving nitroimidazole and anhydrous potassium carbonate in ultra-dry N,N-dimethylformamide, stirring at room temperature, and adding tert-butyl N-(3-bromopropyl)carbamate, and after the reaction is completed, subjecting the reaction mixture to suction filtration and extraction, drying the organic phase, and purifying to obtain a yellow-green oily compound, and deprotecting the yellow-green oily compound with trifluoroacetic acid to obtain a white solid intermediate 1;
• (2) dissolving (S)-4-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-5-(tert-butoxy)-5-oxopentanoic acid in ultra-dry N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, and adding the white solid intermediate 1 obtained in the step (1), after the reaction is completed, extracting the reaction mixture, drying the organic phase, and purifying to obtain a pale yellow solid, deprotecting the pale yellow solid with trifluoroacetic acid to obtain a yellow oily substance, dissolving the yellow oily substance in N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, adding FAPI deprotected with trifluoroacetic acid to remove a Boc group (specifically comprising (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyano-4,4-difluoro-1-pyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyanopyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (1S,4S)-tert-butyl 5-(3-((4-((2-((S)-2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)oxy)propyl)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate, (S)-tert-butyl 4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate), and after the reaction is completed, extracting the reaction mixture, drying the organic phase, and purifying to obtain a pale yellow oily substance, and deprotecting the pale yellow oily substance with diethylamine to obtain a pale yellow oily intermediate 2 (NI-FAPI);
• (3) dissolving FAPI (specifically comprising (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyano-4,4-difluoro-1-pyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyanopyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (1S,4S)-tert-butyl 5-(3-((4-((2-((S)-2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)oxy)propyl)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate, (S)-tert-butyl 4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate) in trifluoroacetic acid, stirring at room temperature, removing the solvent by rotary evaporation to obtain a yellow oily substance, dissolving the yellow oily substance in anhydrous acetonitrile, adding anhydrous potassium carbonate, stirring at room temperature, adding a PEG chain (BocNH(CH2CH2O)nCH2CH2Br) under ice bath, refluxing the mixture to react overnight, subjecting the reaction mixture to suction filtration, removing the solvent by evaporation, and purifying to obtain a pale yellow oily intermediate 3 (PEGn-FAPI);
• (4) dissolving a chelating agent in ultra-dry N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, and adding N-Cbz-1,2-ethanediamine, and after the reaction is completed, extracting the reaction mixture with ethyl acetate and saturated brine, drying the organic phase with anhydrous sodium sulfate, purifying by silica gel column chromatography to obtain a yellow solid, and deprotecting the yellow solid with hydrogen to obtain a white solid substance;
• and dissolving 3,3′-(((2,2,13,13-tetramethyl-4,11-dioxo-3,12-dioxa-6,9-diazatetradecane-6,9-diyl)bis(methylene))bis(4-hydroxy-3,1-phenylene))dipropanoic acid (HBED-CC(tBu)2) in ultra-dry N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, and adding the white solid substance, and after the reaction is completed, extracting the reaction mixture, drying the organic phase, and purifying to obtain a colorless solid intermediate 4 (Chelator-HBED-CC(tBu)2);
• (5) dissolving a chelating agent in ultra-dry N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, and adding the intermediate 2 prepared in the step (2) or FAPI deprotected with trifluoroacetic acid to remove a Boc group (specifically comprising (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyano-4,4-difluoro-1-pyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyanopyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (1S,4S)-tert-butyl 5-(3-((4-((2-((S)-2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)oxy)propyl)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate and (S)-tert-butyl 4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate);
• and after the reaction is completed, extracting the reaction mixture, drying the organic phase, purifying to obtain a pale yellow oily substance, deprotecting the pale yellow oily substance with trifluoroacetic acid, and purifying by semi-preparative HPLC to obtain a Chelator-NI-FAPI or Chelator-FAPI labeling precursor;
• (6) dissolving a chelating agent in ultra-dry N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, and adding the intermediate 1 prepared in the step (1) to react at room temperature overnight, after the reaction is completed, extracting the reaction mixture, drying the organic phase, purifying to obtain a yellow oily substance, dissolving the yellow oily substance in ultra-dry N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, and adding FAPI deprotected with trifluoroacetic acid to remove a Boc group (specifically comprising (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyano-4,4-difluoro-1-pyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyanopyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (1S,4S)-tert-butyl 5-(3-((4-((2-((S)-2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)oxy)propyl)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate and (S)-tert-butyl 4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate) to react at room temperature overnight, and after the reaction is completed, extracting the reaction mixture, drying the organic phase, purifying to obtain a pale yellow oily substance, deprotecting the pale yellow oily substance with trifluoroacetic acid, and purifying by semi-preparative HPLC to obtain an NI-Chelator-FAPI labeling precursor;
• (7) dissolving the intermediate 4 prepared in the step (4) in N,N-dimethylformamide, adding 2-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate and N,N′-diisopropylethylamine under ice bath and stirring, and adding FAPI deprotected with trifluoroacetic acid to remove a Boc group (specifically comprising (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyano-4,4-difluoro-1-pyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (S)-6-[3-(4-Boc-1-piperazinyl)propoxy]-N-[2-(2-cyanopyrrolidinyl)-2-oxoethyl]quinoline-4-carboxamide, (1S,4S)-tert-butyl 5-(3-((4-((2-((S)-2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)oxy)propyl)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate and (S)-tert-butyl 4-(3-((4-((2-(2-cyano-4,4-difluoropyrrolidin-1-yl)-2-oxoethyl)carbamoyl)quinolin-6-yl)(methyl)amino)propyl)piperazine-1-carboxylate) or the intermediate 3 prepared in the step (3), and after the reaction is completed, extracting the reaction mixture, drying the organic phase, purifying to obtain a pale yellow oily substance, deprotecting the pale yellow oily substance with trifluoroacetic acid, and purifying by semi-preparative HPLC to obtain a Chelator-HBED-CC-(PEG)n-FAPI labeling precursor;
• and
• (8) dissolving the labeling precursors obtained in the steps (5), (6) and (7) in dimethyl sulfoxide, adding a sodium acetate buffer solution and a radionuclide-containing solution, and heating to obtain a corresponding radiolabeled product.