Simple synthesis of new carbon-11-labeled 1,2,4-triazolo[4,3-a]quinoxalin-1-one derivatives for PET imaging of A3 adenosine receptor

• Published in: Applied radiation and isotopes 2014-09, Vol.91, p.71-78
• Main Authors: Gao, Mingzhang, Gao, Andy Chufan, Wang, Min, Zheng, Qi-Huang
• Format: Article
• Language: English
• Subjects: A3 adenosine receptor; Cancer; Carbon Radioisotopes - chemistry; Carbon-11-labeled 1,2,4-triazolo[4,3,a]quinoxalin-1-one derivatives; Cardiac diseases; Isotope Labeling - methods; Magnetic Resonance Spectroscopy; Neurological disorders; Positron emission tomography (PET); Positron-Emission Tomography - methods; Quinoxalines - chemical synthesis; Quinoxalines - chemistry; Radiopharmaceuticals - chemical synthesis; Radiopharmaceuticals - chemistry; Receptor, Adenosine A3 - analysis; Spectrometry, Mass, Electrospray Ionization; Triazoles - chemical synthesis; Triazoles - chemistry
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2014.05.005

The reference standards 4a-b, 6a-b, 7a-c, and desmethylated precursors 9a-b, 10a-b, 8a-c were synthesized from 4-methoxyaniline, ethyl 2-chloro-acetoacetate and substituted benzene-1,2-diamines with 3, 5, 6 steps in 61–67%, 34–41%, 23–31%, and with 4, 6, 7 steps in 49–57%, 28–35%, 20–27% overall chemical yield, respectively. The target tracers [11C]4a-b, [11C]6a-b, [11C]7a-c were synthesized from their corresponding precursors with [11C]CH3OTf through O-[11C]methylation and isolated by simplified SPE in 40–60% decay corrected radiochemical yields at EOB, with 185–370GBq/μmol specific activity at EOS. •New 1,2,4-triazolo[4,3-a]quinoxalin-1-one derivatives were synthesized.•New 11C-labeled 1,2,4-triazolo[4,3-a]quinoxalin-1-one derivatives were synthesized.•A simplified SPE technique was employed in radiosynthesis.