PPA IIF t--XII, R= CHO anthracene by heating with polyphosphoric acid (PPA) followed by heating with sulfur to dehydrogenate afforded only a 10% yield of IIF. However, oxidation of XI to XII, using Sarett's reagent, la followed by heating of XI1 with PPA resulted in high yields of IIF, which was shown to be identical with IIF prepared as described. 12 The above method of converting X to IIF is to be preferred to t, he earlier synthesis12 as a higher over-all yield ...
![Benz[a]anthracene,5-fluoro- Structure](https://image.chemsrc.com/caspic/328/388-68-1.png)