Structure Elucidation of Natural Organic Compounds by NMR

Abstract

This article deals with how modern and advanced NMR techniques (mainly various 2 D ones) are manipulated for the structure elucidation of natural organic compounds by giving the examples which the author has been involved in. Examples shown here are a) urochordamines A and B, larval settlement/metamorphosis-promoting alkaloids from some ascidians, b) a novel kind of bile acid in chronic subdural hematoma, as an example for application of a very small amount of sample (ca. 70 μg), c) 2-isocyanoallopupukeanane, a new sesquiterpene with a novel tricylic skeleton from nudibranchs, d) a skeletally rearranged product from a derivative of terrecyclic acid A, as an example for utilization of 13C-labelled compounds and 2 D-INADEQUATE experiment, and e) orbiculamide A, a novel cytotoxic cyclic peptide from a marine sponge. Several new NMR techniques not mentioned in the examples are also listed. © 1993, The Society of Synthetic Organic Chemistry, Japan. All rights reserved.