Structure and absolute configuration of pyrophen,a novel pryrone derivative of L-phenylalanine from Aspergillus niger

Pyrophen, a novel 4-methoxy-2-pyrone derivative of L-phenylalanine isolated from cultures of Aspergillus niger, crystallizes in the orthorhombic space group P2₁2₁2₁, with a = 8.918(1), b = 9.199(3), and c = 18.092(4) Å. The structure was solved by direct methods and the absolute configuration assigned by the Bijvoet method. Refinement gave R = 0.045 and S = 1.78 for 1677 reflections with I > 3σ(I). Though numerous other pyrone natural products are known, including other products of A. niger, this is the first report of an amino acid-pyrone derivative.