Nitrofluorenes

In a 2-1. three-necked round-bottomed flask, equipped with a mechanical stirrer (Note 1), reflux condenser, and dropping funnel, are placed 30 g. of pure 2-nitrofluorene, m.p. 157° [Org. Syntheses, Coll. Vol. 2, 447 (1943)], and 250 ml. of 95% ethanol. After warming to 50° on a steam bath, 0.1 g. of palladized charcoal catalyst (previously moistened with alcohol) is added (Note 2) and the stirrer is started. About 15 ml. of hydrazine hydrate is added from the dropping funnel during 30 minutes (Note 3). At this point an additional 0.1 g. of catalyst (previously moistened with alcohol) is added and the mixture is heated until the alcohol refluxes gently. After 1 hour the nitrofluorene has dissolved completely and the supernatant liquor is almost colorless. 

Nitrofluorene (13, 74) In a yield of 70 per cent by passing nitrous vapors into a benzene solution of fluorene. Monti, Martello, and Valente, Gazz. chim. ital. 66, 31 (1936). 

Certain nitro PAHs appear to require metabolism of their N-hydroxy arylamine derivatives in order to induce mutations. For example, while 2-nitrofluorene showed decreased mutagenicity in the nitroreductase-deficient mutant, TA98NR, and in strain TA98/1,8-DNP, its presumed ultimate mutagenic derivative, N-hydroxy-2-aminofluorene was inactive in only strain TA98/1,8-DNP (117). Observations such as these led McCoy t al. (117) to... 

Figure 13 Chromatogram of an airborne particulate sample. Peaks 1 = 1,6-dinitropyr-ene 2 = 1,8-dinitropyrene 3 = 1,3-dinitropyrene 4 = 2-fluoro-7-nitrofluorene 5 = 1-nitropyrene. (From Ref. 60.)...

Condensations with alkyl nitrites and nitrates, however, are not so generally applicable as the true ethyl acetoacetate reaction, and the possibility is not excluded that they proceed in another way compounds with mobile hydrogen might first he added to the inorganic part of the ester by means of an aldol condensation. The fact that fluorene, which contains no active double bond at all, combines with ethyl nitrate (as well as with ethyl oxalate) and sodium ethoxide in the same way, yielding oci-nitrofluorene, seems to support this second theory (W. Wislicenus). 

Attempts at correlation analysis for X—C—H acidity have been made for a long time. Bowden and colleagues192 examined the problem in 1970 for the pKa values of 9-X-fluorenes and related series. For a limited selection of substituents X in 9-X-fluorenes, a correlation with Taft s a values for X was found89. A more general correlation, albeit with considerable scatter, was found with AM, a parameter based on LCAO-MO calculations. Several dinitro-substituted diphenylmethanes fitted the line quite well and 2-nitrofluorene fitted passably 9-cyanofluorene also fitted quite well, but malononitrile deviated strongly. 

Group I comprises nitroaromatics with lowest (n, tt )- [or (7t,n )- with considerable (n, 7T )-contribution] excited states, the triplets of which behave electro-philiccilly and tend to abstract hydrogen atoms or electrons and thus typically undergo photoreduction. Compounds which fit this correlation were Nitrobenzene 2-nitro-, 4-nitro- and 4,4 -dinitrobiphenyl, 2-nitrofluorene, 3-nitroaceto-phenone, 1,8- and 1,5-dinitronaphthalene. 

Iodo-7-nitrofluorene gave 2-iodo-7-aminofluorene in 85% yield by reduction with hydrazine in the presence of Raney nickel [277], and 2-iodo-6-nitronaphthalene and 3-iodo-6-nitronaphthalene afforded the corresponding iodoaminonaphthalenes in almost quantitative yields on treatment with aqueous-alcoholic solutions of sodium hydrosulfite (hyposulfite, dithionite) [257]. 

Direct mutagenicities (rev/nmol -S9) for both the plate incorporation and microsuspension assay are given in Table 10.20 for four isomeric nitrofluorenes and four nitrophenanthrene lactones (Arey et al., 1992 Atkinson... 

TABLE 10.20 Direct Mutagenicities in Strain TA98 ( — S9) for 1- and 2-Nitronaphthalene and Several Nitrofluorenes and Nitrodibenzopyranones in the Salmonella typhimurium Plate Incorporation and Microsuspension Preincubation Assays"... 

---