On the Combined Action of Iodine and a Sulfuric–Nitric Acid Mixture on Fluoranthene and Fluorenone-5-carboxylic Acid

A. N. Novikov, A. M. Sedov

(Presented by the scientific-methodological seminar of the Faculty of Chemical Technology)

At the present time, research is being expanded in every way on the development of one-stage methods for obtaining organic substances. This direction is of particular interest for the synthesis of derivatives of aromatic hydrocarbons containing several different substituents.

Earlier, using several objects, we showed that iodine and a nitro group can be introduced simultaneously by the action on the corresponding hydrocarbon of iodine and a sulfuric–nitric acid mixture [1].

Extending this method, from fluoranthene and fluorenone-5-carboxylic acid we obtained in one stage the previously undescribed 3-iodo-8-nitrofluoranthene and 2-iodo-7-nitrofluorenone-5-carboxylic acid. The structure of 3-iodo-8-nitrofluoranthene was established by IR spectroscopy, and also on the basis of the rules for electrophilic substitution in the fluoranthene series [2]. The presence in the spectrum of iodonitrofluoranthene of absorption bands at 1450 cm\(^{-1}\) and 1425 cm\(^{-1}\) confirms substitution at positions 3 and 8 of the fluoranthene molecule [3]. The structure of 2-iodo-7-nitrofluorenone-5-carboxylic acid was proved by converting it, through decarboxylation in pyridine, into the known 2,7-iodonitrofluorenone.

Experimental Part

Synthesis of 3-iodo-8-nitrofluoranthene

10.1 g (0.05 M) of fluoranthene, 6.35 g (0.05 g-at.) of iodine, and 40 ml of glacial acetic acid were placed in a flask. At 40–43°C and with mechanical stirring, a mixture of 5.3 ml of nitric acid, \(d\) 1.4, and 7.9 ml of sulfuric acid, \(d\) 1.83–1.84, was gradually added to the flask over the course of 1 hour. After addition of the nitrating mixture, the synthesis was completed after 30 minutes. After cooling, the reaction mass was diluted with water; the precipitate was filtered off, washed with water, and recrystallized from toluene. Yield of 3-iodo-8-nitrofluoranthene: 10.2 g (55%). M.p. 220–221°C.

Found, %: I 34.21; N 12.33.

Calculated, %: I 34.04; N 12.51.

Synthesis of 2-iodo-7-nitrofluorenone-5-carboxylic acid

Into a round-bottomed three-necked flask were charged 5.6 g (0.025 M) of fluorenone-5-carboxylic acid, 3.17 g (0.025 g-at.) of finely ground iodine, and

100 ml of glacial acetic acid. At a temperature of 117–120°C, over the course of 2.5 hours, a sulfuric–nitric acid mixture consisting of 30 ml of nitric acid, \(d\ 1.4\), and 45 ml of sulfuric acid, \(d\ 1.83\text{–}1.84\), was added dropwise. After addition of the sulfuric–nitric acid mixture, stirring was continued for another 0.5 hour. The reaction mass was then diluted with water; the precipitate that formed was filtered off, washed with water, and recrystallized from acetic acid. Yield of 2-iodo-7-nitrofluorenone-5-carboxylic acid: 5.2 g (53%).

M.p. 263–264°C.

Found, %: I 31.75; N 3.78.

Calculated, %: I 32.15; N 3.57.

Conclusions

3-Iodo-8-nitrofluoranthene was obtained in one step in 55% yield, and 2-iodo-7-nitrofluorenone-5-carboxylic acid in 53% yield, by the direct action of iodine and a sulfuric–nitric acid mixture on fluoranthene and fluorenone-5-carboxylic acid.

REFERENCES

1. A. N. Novikov, T. A. Khalimova. ZhVKhO im. D. I. Mendeleeva, VII, 698 (1962).
2. N. Campbell, N. H. Keir, J. Ch. Soc., 1233 (1955).
3. P. Cornelia, M. Ginseppe, F. Ginò, T. Ginseppe. Gazz. Chim. ital., 97, 1701 (1967).