Acremolin from Acremonium strictum is N²,3-Etheno-2′-isopropyl-1-methylguanine, not a 1H‑Azirine. Synthesis and Structural Revision

The first synthesis of the heterocyclic marine natural product, acremolin, is reported along with the revision of the structure from a 1H-azirine to a substituted N²,3-ethenoguanine (5-methyl-7-isopropyl-4,5-dihydroimidazo[2,1-b]purine). Additional properties of acremolin are also described including its ¹H–¹⁵N-HMBC and fluorescence spectra.