Tanzawaic acids I–L: Four new polyketides from Penicillium sp. IBWF104-06

• Louis P. Sandjo,
• Eckhard Thines,
• Till Opatz and
• Anja Schüffler

Beilstein J. Org. Chem. 2014, 10, 251–258, doi:10.3762/bjoc.10.20

• 1.39 (H-7). The foregoing data in conjunction with those of the structurally related tanzawaic acid E [2] led to the identification of 1 as a new member of this compound class and it was given the name tanzawaic acid I (Figure 5). Compound 2 has the molecular formula C18H26O4 deduced from its NMR and

• the tanzawaic acid family and was given the name tanzawaic acid J. The molecular formula of compound 3, C18H26O3 was established by NMR in conjunction with HRMS-ESI which gave a pseudo-molecular ion at m/z 313.1788 (calcd for [M + Na]+: 313.1780). This composition required six double bond equivalents

• relative orientation of the side chain and the CH3 group (Figure 3) which is supported by a correlation between H-5 and the CH3 (C-16) group (δH 1.18). The complete assignment led to structure 3 as shown in Figure 5. The compound was named tanzawaic acid K. The molecular formula of compound 4, C18H24O3 was