Complete 1H and 13C NMR assignments of three labdane diterpenoids isolated from Leonotis ocymifolia and six other related compounds

Abstract

AbstractUnambiguous and complete assignments of 1H and 13C NMR chemical shifts for three structurally complex labadane diterpenoids isolated from Leonotis ocymifolia (leonotin, leonotinin and nepetaefolin) and six other related compounds (hispanolone, 7α‐ and 7β‐hispanols, marrubiin, villenol and andalusol), previously isolated from Labiatae species, are presented. The assignments are based on 2D shift‐correlated [1H, 1H‐COSY, 1H, 13C‐gHSQC–1J(C,H), 1H,13C‐gHMBC–nJ(C,H) (n = 2 and 3)] and DPFGSE 1D‐NOE experiments. Copyright © 2003 John Wiley & Sons, Ltd.