The fungus Verticillium lamellicola affords lamellicolic anhydride 1 (5-methyl-2, 4.7- trihydroxy-1, 8-naphthalic anhydride) together with small amounts of the quinone 2, the carbonate 3 and the chloro compound 4. Selective reactions of the functional groups in these and their derivatives have been used to interrelate these and effect conversion of 1 into 18, the anhydride obtained from Penicillium herquei.
![(5-formyl-8-hydroxymethyl-9-oxo-5,5a,9,11,11a,12-hexahydro-indolizino[1,2-b]quinoline-7-yl)-malonic acid di-tert-butyl ester Structure](https://image.chemsrc.com/caspic/192/41758-46-7.png)