The antimicrobial agent pramanicin (1), and a related fatty acid (6), were isolated from a corn-based solid or a lactosecontaining liquid fermentation of a sterile fungus found growing in grass. The structures of these compounds were determined by a variety of spectral means including UV, IR, and NMR spectroscopy, as well as mass spectrometry. A number of chemical derivatives are also presented here. Pratnanicin represents a new class of atttimicrobii agents containing a highly functional&d head group and functionalized fatty side chain. The search for novel antifungal agents has led to the discovery of a wide variety of compounds which can be described in a general fashion as having a polar, highly functionalized head group and simple fatty side chains. Included in this group are restricticin*a, pneumocandinstb, sphingofunginsles papulacandinsld, L-657,398le. and lipoxymycin lf. In spite of their general structural similarity, the target of these antifungal agents is highly variable and includes the sterol biosynthesis pathway, sphingolipid biosynthesis pathway and cell wall biosynthesis. In this paper the isolation, structure determination and chemical derivatization of 1, an antimicrobial agent which contains both a highly functionalized head group and functionalized side chain, as well as the naturally-occuring side chain itself (a), will be described.