Concise Preparation of 1,8-Diazaanthracene-2,7,9,10-Tetraones. Two Alternative Syntheses of the Natural Antifolate Diazaquinomycin A

✍ Scribed by José Marı́a Pérez; Pilar López- Alvarado; Eva Pascual-Alfonso; Carmen Avendaño; J. Carlos Menéndez

• Book ID: 104202752
• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 185 KB
• Volume: 56
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(00)00371-9

✦ Synopsis

AbstractÐTreatment of compounds bearing one or two 1-dimethylamino-1,4-dihydropyridine moieties with the urea-hydrogen peroxide complex (UHP) led to their ef®cient aromatization. Double N-oxidation of 1,8-diazaanthraquinones thus obtained is the ®rst example of a double N-oxidation of a diaza heterocycle by UHP in tri¯uoroacetic acid. Treatment of the crude double N-oxides with tosyl chloride in acetonitrile±water afforded 1,8-diazaanthracene-2,7,9,10-tetraones (including diazaquinomycin A) in 25±40% overall yields. An alternative synthesis of diazaquinomycin A was also devised, whose key steps are the hetero Diels±Alder reaction between 2-methyl-2-hexenal dimethylhydrazone and 3-methyl-4-propyl-2H-quinoline-2,5,8-trione and the oxidative functionalization of the 1,8-diazaanthracene-2,9,10-trione derivative thus obtained.