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128. Syntheses and Reactions of Amino- and Azidophenalenones

Stadlbauer W., Fischer M., Lackner N.,
in Proceedings of ECSOC-18, The Eighteenth International Electronic Conference on Synthetic Organic Chemistry, November 1-30, 2014;
http://www.sciforum.net/conf/ecsoc-18; http://www.sciforum.net/presentation/1012;
J. A. Seijas, M. P. Vázquez Tato, S. K. Lin (Eds). CD-ROM edition, ISBN 3-906980-26-x, Published in 2014 by MDPI AG, Basel, Switzerland.

Abstract:

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


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