CXXIII.—The colour and constitution of the aminocoumarins

4-Bromomethyl-7-methyl-6,8-dinitrocoumarin

“…This is in agreement with the ab initio calculations on 6-methyl-4-bromomethylcoumarins (Sortur et al, 2006). Positions C-6 and C-8 (refers to positions from systematic naming scheme) become activated due to the electron donating methyl group at C-7 and hence nitration occurs at C-6 and C-8 consistent with the title compound which is also in agreement with earlier reports (Clayton, 1910;Kulkarni et al, 1983).…”

“…For background information on the nitration of coumarin compounds, see: Kulkarni et al (1983); Clayton et al (1910). For a related structure, see: Vasudevan et al (1990).…”

The Chemistry of Coumarins.

“…Clayton (50) observed that coumarin was found to resist strongly the introduction of more than one nitro group, but this resistance diminishes very appreciably with the introduction of alkyl groups in the molecule: he found that when 8-nitrocoumarin is nitrated, the second nitro group goes to the 6-position, and that when 6-nitrocoumarin is nitrated, 3,6-dinitrocoumarin is obtained. The presence of a nitro group in the 3-position is shown by the reaction with alkali.…”

Novel pyrrolocoumarin derivatives

“…4,7-Dimethyl-6-aminocoumarin 1 has been prepared by reduction of 4,7-dimethyl-6-nitrocoumarin (8) with powder of cast iron in a mixture of dioxan-water and pH = 4−5. This procedure is more convenient and provides a better yield of 1 than the syntheses reported previously (4).…”