3-Hydroxyphenalenones 3, react by electrophilic halogenation to 2-chlorophenalenediones 4 or 2-iodophenalenone 5. The chloro group of 4 was exchanged against azide by reaction with sodium azide to give 2-azidophenalenediones 6. Nucleophilic chlorination of 3 furnishes 3-chlorophenalenones 7, which were converted to 3-azidophenalenones 8. Staudinger reaction of 8 with triphenylphosphane gave phosphazenes 9 which hydrolyzed to 3-aminophenalenones 10. Amines 10 can also be obtained directly from 3-hydroxyphenalenones 3 and ammonium acetate, or by catalytic hydrogenolysis of azides 8. Nitration of 3-hydroxyphenalenone 3 with nitric acid forms 2-nitrophenalenone 11, which was converted to 3-chloro-2-nitrophenalenone 12. Azidation, however, formed 2,3-diazidophenalenone 13.
2-Amino-3-hydroxyphenalenone 14 or 3-azidophenalenone 8 cyclize with carboxylic acid derivatives to oxazolo-phenalenones 15. 2-Acetylphenalenone 21 leads via the intermediate oxime 22 to an isomer mixture of isoxazolophenalenone 23 as main product and oxazolophenalenone 15 as by-product