What is "xantocillin"

n. The first reported natural product found to contain the isocyanide functional group, originally isolated from ''Penicillium notatum'' in 1950.

Xantocillin ( INN), also known as xanthocillin X or ophthocillin, was the first reported natural product found to contain the isocyanide functional group. It was first isolated from Penicillium notatum by Rothe in 1950 and subsequently from several other sources.