New quinazolinone alkaloids within rare amino acid residue from coral-associated fungus, Aspergillus versicolor LCJ-5-4.

Cottoquinazoline D (3), a new alkaloid with a 1-aminocyclopropane-1-carboxylic acid residue rarely discovered in nature, was isolated and identified together with two new quinazolinone alkaloids, cottoquinazolines B (1) and C (2), from coral-associated fungus Aspergillus versicolor LCJ-5-4. Their structures including absolute configurations were elucidated based on spectroscopic methods, X-ray single crystal diffraction analysis, and chemical methods. A possible biogenetic pathway for them was proposed.