Veratrole nitration

Recently, nitration of organolithiums and Gngnards v/iih has been developed for the preparation of certain kmds of nitro compounds fEqs. 2.14 and 2.15. The success of this process depends on the reaction conthdons (low remperanirei and the stnicnire of substrates. For example, 3-nitrothiophene can be obtained in 70% overall yield from 3-bromothiophene this is far superior to the older method. 3-Nitroveratrole cannot be prepared usefully by classical electrophilic nitradonof veratrole, but it can now be prepared by direct orr/io-lithiadon followed The mechanism is believed to proceed by dirutrogen rathcal, followed by the rathcal s combinadon. 

Trinitroveratrole , crysts (from benz or acet acid), mp 144—45° sol in hot ale, eth, toluene or butanol si sol in w, heptane methanol prepd by nitration of veratrole with coned HNOa H2S04 at 100°(Ref 5)... 

Twenty-five grams (0.18 mole) of veratrole (p. 298) is added slowly with stirring and careful cooling to a mixture of 20 ml. of water and 20 ml. of concentrated nitric acid (sp. gr. 1.42). The chocolate-colored crude nitration product (28 g.) is removed by filtration, washed with water, and recrystallized twice from aqueous ethanol. There is obtained 19 g. (55%) of 4-nitroveratrole, m.p. 97.5 ... 

One might imagine that these comprehensive data on anisole would enable us to predict the intramolecular selectivity of nitration of veratrole (1,2-dimethoxybenzene) with some success. Veratrole is nitrated at the limiting rate (Figure 5). (19) The... 

Gallium(in)- and iron(lll)-promoted SZ can be supported on mesoporous materials such as MCM-41 silica [86]. The catalysts, named GaSZ/MCM-41 and FeSZ/MCM-41, respectively, are prepared by incipient wetness impregnation using zirconium(lV) sulfate as the precursor in combination with gallium(ni) nitrate or ferric nitrate and calcined at 700°C for 3 h. These catalysts were studied in the acylation of veratrole with acetic anhydride the reaction gives only 3,4-dimethoxyacetophenone. The most active catalyst is GaSZ/MCM-41 (78% yield, 100% selectivity), followed by SZ/MCM-41 alone (68% yield, 100% selectivity) in the reaction carried out at 80°C for 3h (Scheme 3.14). 

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