The expeditious synthesis of an API building block, 2-cyanothiazole,
from cyanogen gas and a readily available dithiane is reported. A
previously undisclosed partially saturated intermediate is formed,
which can be further functionalized and isolated by the acylation
of the hydroxy group. Dehydration using trimethylsilyl chloride furnished
2-cyanothiazole, which could be further converted to the corresponding
amidine. The sequence provided a 55% yield over 4 steps. We envision
that this work will spark further interest in cyanogen gas as a reactive
and cost-effective synthetic reagent.