2-Aryl-1,4-benzoquinones 1a-h (aryl = RC6H4, R = H, 4-Me, 3-CF3, 4-COOH, 3-Cl, 4-Cl, 4-F, 4-NO2) react with methyl 2a and ethyl 2b cyanoacetates in the presence of some bases to form dialkyl 2,6-diamino-4-arylfuro[2_,3_:4,5]benzo[b]furan-3,7-dicarboxylates 3a-l. Regardless of the reagents ratio benzodifuran derivatives are formed selectively. Only in reaction of 2-(4-nitrophenyl)-1,4-benzoquinone 1h with 2b ethyl 2-amino-5-hydroxy-4-(4-nitrophenyl)benzo[b]furan-3-carboxylate 4 is formed as minor component besides of 3l. Starting compounds 1a-h are prepared by arylation of the 1,4-benzoquinone with arenediazonium chlorides (Meerwein reaction).
DBU/MgCl2 mediated reaction between nitroarenes and some CH acids bearing leaving group lead to 2,1-benzisoxazole derivatives under aprotic conditions. Ortho-directing effect was observed.
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