The Ghanian plant Cryptolepis sanguinolenta is the source of a series of fascinating indoloquinoline alkaloids. The most unusual member of this alkaloid series was initially proposed to be a spiro nonacyclic structure, named cryptospirolepine, and was elucidated in 1993 based on the technologies available at that time. There were, however, several annoying attributes to the structure that bothered analysts for the ensuing 22 years. During the two decades that followed the initial work there have been enormous developments in NMR technology. Using new experimental approaches, specifically homodecoupled 1,1- and 1,n-HD-ADEQUATE NMR experiments developed in 2014, the structure of only a 700 µg sample of cryptospirolepine has been revised and is shown on the cover of this volume. The confluence of the NMR technological and methodological advances that allowed the revision of the structure of cryptospirolepine using a submilligram sample seems a fitting example for this book, which is dedicated to the NMR characterization of various classes of natural products.

Application of the Nuclear Overhauser Effect to the Structural Elucidation of Natural Products; Assigning Molecular Configuration by Nuclear Magnetic Resonance; Nuclear Magnetic Resonance Experiments Applicable to the Elucidation and Characterization of Nitrogenous Natural Products: 1H-15N Heteronuclear Shift Correlation Methods; Application of Residule Dipolar Couplings to the Structural Analysis of Natural Products; Applications of High-resolving Power, High-accuracy Mass Spectrometry for the Structural Elucidation of Natural Products; Current Pulse Sequence Developments in Small-molecule Nuclear Magnetic Resonance Spectroscopy; Terpenes: Mono-, Sesqui-, and Higher Terpenes; Nuclear Magnetic Resonance of Steroids; Nuclear Magnetic Resonance Experiments Applicable to the Elucidation and Characterization of Alkaloid Structures Part 1: Direct 1H-13C Heteronuclear Shift Correlation and Establishing Contiguous Protonated Carbon Spin Systems; Nuclear Magnetic Resonance Experiments Applicable to the Elucidation and Characterization of Alkaloid Structures Part 2: Advanced Techniques for the Identification of Adjacent Carbons Using H2BC,1,1-ADEQUATE, and Variants; Nuclear Magnetic Resonance Case Studies in Marine Natural Products; Nuclear Magnetic Resonance Case Studies in Microbial Natural Products; Nuclear Magnetic Resonance in Saponin Structure Elucidation; Increasing the Adoption of Advanced Techniques for the Structure Elucidation of Natural Products