A novel no-carrier-added submicromolar scale radiosynthesis of [S-methyl-14C]-florfenicol

• Published in: Journal of labelled compounds & radiopharmaceuticals 2013-06, Vol.56 (8), p.382-384
• Main Authors: Srinivas, G., Prabhakar, G., Unny, V. K. P., Sudhakar, K., Mukkanti, K., Choudary, B. M.
• Format: Article
• Language: English
• Subjects: [14C]-methyl iodide; Carbon Radioisotopes - chemistry; Chemistry Techniques, Synthetic - methods; Isotope Labeling - methods; radioisotopically labeled florfenicol; radiosynthesis of [S-methyl-14C]-florfenicol; S-methylation; Sulfuric acid; Thiamphenicol - analogs & derivatives; Thiamphenicol - chemical synthesis
• ISSN: 0362-4803; 1099-1344
• DOI: 10.1002/jlcr.3053

In this paper is reported a novel reaction scheme for the no‐carrier‐added submicromolar scale radiosynthesis of [S‐methyl‐14C]‐florfenicol that has been newly designed, developed and employed by us successfully. The [14C]‐product was obtained in an overall radiochemical yield of 30% based on [14C]‐methyl iodide taken for the reaction with a radiochemical purity of more than 96%. The specific activity of the product was ~50 mCi (1.85 GBq)/mmol. Chlorosulfonation of compound I was followed by sodium salt formation in situ and it was succeeded by the introduction of [14C]‐methyl group by coupling with [14C]‐CH3I. Subsequently, the oxazolidin‐2‐one protecting group was opened up by a reaction with sulfuric acid in dioxane and later, the amino group was dichloroacetylated with methyl‐2,2‐dichloroacetate in triethylamine to obtain [S‐methyl‐14C]‐florfenicol. A novel method employing a newly designed reaction scheme for the no‐carrier‐added submicromolar scale radiosynthesis of [S‐methyl‐14C]‐florfenicol has been developed and reported in this paper. An overall radiochemical yield of 30% based on [14C]‐methyl iodide was obtained. The radiochemical purity of the final product obtained was more than 96% and specific activity was ~50 mCi (1.85 GBq)/mmol.