Carbon-14 and tritium labeled guanadrel sulfate

Carbon‐14 and tritium labeled (1,4‐dioxaspiro[4.5]dec‐2‐ylmethyl)guanidine sulfate, or guanadrel sulfate Guanadrel sulfate is the USAN name for (1,4‐dioxaspiro[4.5]dec‐2‐ylmethyl) guanidine sulfate. (1) were synthesized. The carbon‐14 label was incorporated into the dioxolane ring portion of guanadrel sulfate. The tritium labels were introduced into the cyclohexane ring portion of the molecule, at the beta and gamma positions with respect to the ketal linkage. The ketal resulting from the reaction of the original 2‐cyclohexen‐1‐one with 3‐phthalimido‐1,2‐propanedial contained a double bond in the β‐γ position rather than the α‐β postion of the original 2‐cyclohexen‐1‐one. This double bond shift provided a convenient method of introducing tritium into the 3‐and 4‐positions of cyclohexanone. Proof of the double bond position is discussed.