Naturally Occurring Nitrogen–Sulfur Compounds. The Benzothiazole Alkaloids

Several alkaloids contain both nitrogen and sulfur, and a subset of these interesting terrestrial and marine natural products – the benzothiazoles – forms the subject of the present short review. Benzothiazole alkaloids are relatively rare in Nature, but they range in structural complexity from benzothiazole itself and simple derivatives thereof, through the well-known firefly luciferin, to more complex molecules such as the thiazo-rifamycins and the dercitin-kuanoniamine family. Although the biosynthesis of benzothiazoles has not been studied in many cases, the evidence suggests that they are derived from cysteine addition to benzoquinone derivatives followed by ring contraction of the resulting benzothiazine adducts. The review also highlights the fact that little synthetic work has been done on benzothiazole-containing natural products.