One‐step radiosynthesis of 4‐[ 18 F]flouro‐3‐nitro‐ N ‐2‐propyn‐1‐yl‐benzamide ([18F]FNPB): a new stable aromatic porosthetic group for efficient labeling of peptides with fluorine‐18

4‐[ 18 F]flouro‐3‐nitro‐ N ‐2‐propyn‐1‐yl‐benzamide ([ 18 F]FNPB) was developed as a new stable aromatic prosthetic group for more efficient click labeling of peptides. A new aromatic precursor 3,4‐dinitro‐ N ‐2‐propyn‐1‐yl‐benzamide was radiofluorinated using [ 18 F]KF/K2.2.2 followed by HPLC purification to obtain the desired product [ 18 F]FNPB. [ 18 F]FNPB was synthesized with a 58% radiochemical yield, a specific activity > 350 GBq/µmol, and radiochemical purity was exceeded 98% in 40 min. The in vitro stability studies showed no detectable radiodefluorination over 2 h in mouse plasma. The click labeling yield of three different peptides with [ 18 F]FNPB were all above 87%. The in vitro study suggests that [ 18 F]FNPB may be stable  in vivo and could have general application in labeling peptides with high radiochemical yield for positron emission tomography applications. Copyright © 2012 John Wiley & Sons, Ltd.