... In the IR spectrum, simple β-thiolactones 15–18 View all references exhibit a carbonyl absorption band in the region 1740–1750 cm −1 (acyclic thioesters absorb at 1690 cm −1 and β-lactones at 1810–1840 cm −1 ... Barbaro , G. , Battaglia , A. and Giorgianni , P. 1987. ... Coyle et al. ...