Synthesis of [3,3‐D₂]4‐hydroxy‐1‐(3‐pyridyl)‐1‐butanone, an internal standard for analysis of tobacco‐specific nitrosamine hemoglobin and DNA adducts

The synthesis of [3,3‐D₂]4‐hydroxy‐1‐(3‐pyridyl)‐1‐butanone ([3,3‐D₂]HPB), an internal standard for the analysis of hemoglobin and DNA adducts of tobacco‐specific nitrosamines, is reported. 3‐Pyridine carboxaldehyde was converted to 2‐(3‐pyridyl)‐1, 3‐dithiane. This was condensed with 2‐(2‐bromoethyl)‐1, 3‐dioxalane to yield 2‐[2‐(3‐pyridyl)‐1, 3‐dithiane]ethyl‐1, 3‐dioxalane. Selective hydroylsis of the aldehyde protecting group produced 4‐(1, 3‐dithian‐2‐yl)‐4‐(3‐pyridyl)‐butanal, which was then labeled with deuterium adjacent to the aldehyde carbonyl group. Reduction with LiAlH₄ produced the corresponding alcohol. Removal of the dithianyl protecting group required protection of the alcohol as its t–butyldimethylsilyl ether. Treatment with AgNO₃/N‐chlorosuccinimide in aqueous CH₃CN produced [3,3‐D₂]HPB.