The niiration of a-phenyl-o-toluic acid with fuming (90%) nitric acid gives a-2.4-dinitrophenyl-5-nitro-o-toluic acid as the major product. Optimum conditions for the preparation, and experiments leading to the structural assignment, are described.
T R E ~~T M E K Tof m-phenyl-o-toluic acid (I) with fuming nitric acid at rooin temperature has been reported to give a mixture of mono-and di-nitro-acids from which the dinitro-acid (11) was isolated. Subsequent oxidation gave the dinitro-o-benzoylbenzoic acid (111). In our hands this procedure repeatedly produced a trinitroderivative as the major product to which we assign structure (IT.'). Some niono-and cii-nitro-acids were probably formed, but these were not isolated. The reason for the difference is not clear, but it is possible that the earlier workers' nitric acid was not as concentrated as the 90:& specified. This could explain the formation of a clinitro-acid as the major product. We here describe our brief study of the nitration of (I).The addition of x-phenyl-o-toluic acid in small portions to a large excess of fuming nitric acid maintained at room temperature gave a yellow solution, which after 26 hr. was quenched in water, giving trinitro-a-phenyl-otoluic acid (IV) in 60--700,/, yield. The amide was prepared in SSY, yield. The same acid was obtained under a variety of conditions. Rapid mixing of (I) with excess of fuming nitric acid caused an exothermic reaction (80-!30n) whicli subsided after a few niinutes ; the acid (11') was obtained in cn. 50:a yield after 26 hr. at room temperature. Heating of the nitration mixture at 85" for 4 hr. gave (IV) in 40% yield. The addition of (I) in small portions to the nitric acid at -15" gave a 6Oq~ yield of (11') after the mixture had been allowed to stand for 28 hr. at that temperature. Maximum yields (80--S5q(1) of (IT.') were obtained by the addition of (I) in small portions to an excess of fuming nitric acid at room temperature, followed by heating at 35-40" for 24 hr. Several unsuccessful attempts were made to
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