A simple, rapid synthesis of caffeine‐1,7‐ 13 CH 3

This paper describes a simple, rapid synthesis of caffeine‐1,7‐ 13 CH 3 produced by the reaction of iodomethane‐ 13 C with 3‐methylxanthine. The synthesis is complete in one day, requires only the most rudimentary laboratory equipment, and is amenable to large scale synthesis. Overall yield after product isolation is 82%, and the product is of 99% chemical purity and 99% isotopic purity.