A new minor diketopiperazine from the sponge-derived fungus <i>Simplicillium</i> sp. YZ-11

<p>Chemical investigation of the cultures of a sponge-derived fungus <i>Simplicillium</i> sp. YZ-11 led to the isolation of a new minor diketopiperazine alkaloid <i>cyclo</i>-(2-hydroxy-Pro-Gly) (<b>1</b>) and a natural lactone (<i>S</i>)-dihydro-5-[(<i>S</i>)- hydroxyphenylmethyl]-2(3<i>H</i>)-furanone (<b>2</b>), together with five known ergostane-type sterols (<b>3</b>–<b>7</b>). Their structures were established based on extensive spectroscopic methods (¹H and ¹³C NMR, ¹H-¹H COSY, HSQC and HMBC) and optical rotation analysis.