Phenylpropane as an Alternative Dearomatizing Unit of Indoles: Discovery of Inaequalisines A and B Using Substructure-Informed Molecular Networking

Inaequalisines A and B (1 and 2), the first examples of hybrid alkylated phenylpropane monoterpene indole alkaloids, were isolated from the roots of Callichilia inaequalis, guided by the combined use of molecular networking and substructure annotation. Their structures, including absolute configuration, were elucidated by spectroscopic methods and ECD calculations. A possible biosynthetic pathway for 1 and 2 was postulated.