1- Methyl-3-nitrobenzene

In the presence of KOH, /m(benzotriazol-l-yl)methane 729 reacts with nitrobenzenes to produce />-(/fc (bcnzo-triazol-lyl)methyl]nitrobenzenes 730 (Scheme 114) <1996TL347>. This vicarious nucleophilic substitution of hydrogen <1991S103> can be considered as a convenient way to />-nitrobenzaldehydes 731. Meta and para substituted nitrobenzenes do not react with compound 729 under these conditions, probably due to steric reasons, but 1-nitronaphthalene reacts producing a naphthalene analog of derivative 730. 

Table 4.3 presents the relative rate constants of the chlorine-to-methoxy substitution in the nitrobenzene series (Epiotis 1973). The methoxide ion replaces chlorine in 4-chloro-3-methyl-nitrobenzene more rapidly than in 6-chloro-3-methylnitrobenzene (Table 4.3, entries 1 and 2). This... 

However, methylating nitrobenzene leads to the formation of meta nitrotoluene because the nitro group is meta directed. 

SYNS (BROMOMETHYL)BENZENE p-(BROMO-METHYL)NITROBENZENE BROMOPHENYL-METHANE (O-BROMOTOLUENE P [Pg.151]

SYNS 4-METHYLNITROBENZENE p-METHYL NITROBENZENE NCI-C60537 4-NITROTOLUENE 4-NITROTOLUOL PNT... 

METHYL NITROBENZENE or 2-METHYLNITROBENZENE or o-METHYL-NITROBENZENE (88-72-2) Combustible liquid (222°F/106°C). Violent reaction with strong acids, alkalis (e.g, sodium hydroxide), ammonia, amines, reducing agents, strong oxidizers. Elevated temperature may cause explosive decomposition. Attacks some plastics, rubber, and coatings. 

The ultraviolet spectrum of methyl nitrobenzene sulphonate in various solvents... 

Reduction of nitroarenes to aminoarenes (1, 440-441). Du Pont chemists have reported an explosion during attempted reduction of 2-chloro-5-methyl-nitrobenzene to the amine by hydrazine and Pd-C. The main product was shown to be 2-chloro-5-methylphenylhydroxylamine arylhydroxylamines are known to decompose violently when heated over 90-100°. 

Another example for the application of the methodology in the chemistry of nitroarenes is the synthesis of fluorine-containing indoles. It has been shown that substitution of hydrogen H-6 in 3-fluoro-4-/ -substituted nitrobenzenes by the action of vicarious chloromethyl phenyl sulfone proceeds selectively in DMSO in the presence of KOH at room temperature to give 4-/ -3-fluoro-6-(phenylsulfonyl-methyl)nitrobenzenes in 60-70% yields (Scheme 23) [101]. 

Nitrobenzene (and many other liquid organic compoimds containing nitrogen) is appreciably toxic and its vapour should not be allowed to escape into the atmosphere of the laboratory the delivery tube of the condenser should pass well into the mouth of the receiver flask. The liquid is also a skin poison if it Is accidentally spilled on the skin, it should be removed by washing with a litt e methylated spirit, followed by soap and warm water. 

Reduction of nitrobenzene in methyl or ethyl alcoholic sodium hydroxide solution with zinc powder leads to azobenzene or hydrazobenzene according to the proportion of zinc powder employed ... 

Equip a 500 ml. three-necked flask with an efficient stirrer (e.g., a Hershberg stirrer. Fig. II, 7, 8) and a reflux condenser stopper the third neck. Place a solution of 30 g. of sodium hydroxide in 100 ml. of water, and also 20-5 g. (17-1 ml.) of pure nitrobenzene in the flask, immerse it in a water bath maintained at 55-60°, and add 21 g. of anhydrous dextrose in small portions, with continuous stirring, during 1 hour. Then heat on a boiUng water bath for 2 hours. Pour the hot mixture into a 1 litre round-bottomed flask and steam distil (Fig. II, 40, 1) to remove aniline and nitrobenzene. When the distillate is clear (i.e., after about 1 htre has been collected), pour the residue into a beaker cooled in an ice bath. The azoxybenzene soon sohdifies. Filter with suction, grind the lumps of azoxybenzene in a mortar, wash with water, and dry upon filter paper or upon a porous plate. The yield of material, m.p. 35-35-5°, is 13 g. Recrystallise from 7 ml. of rectified spirit or of methyl alcohol the m.p. is raised to 36°. ... 

Support a 1500 ml. three-necked flask, equipped with a mercury-sealed stirrer and a double surface reflux condenser, on a water bath, and place a solution of 84 g. of sodium hydroxide in 185 ml. of water, 50 g. (41-5 ml.) of nitrobenzene and 500 ml. of methyl alcohol in the flask. Add 70 g. of zinc powder (1), start the stirrer, and reflux for 10 hours. The solution gradually assumes the reddish colour of azobenzene and then on further... 

Steam distil from a 1 - 5 litre three-necked flask until the odour of nitrobenzene is no longer perceptible in the distillate (6-12 hours). Extract the cold residue with three 100 ml. portions of ether, dry the combined extracts with anhydrous magnesium sulphate, and distil oflF the ether. The residue solidifies and consists of almost pure methyl P-naphthyl ketone, m.p. 52° the yield is 30 g. Upon recrystallisation from glacial acetic acid, the m.p. is raised to 54°. 

The commercial product, m.p. 53-55°, may be used. Alternatively the methyl -naphthyl ketone may be prepared from naphthalene as described in Section IV,136. The Friedel - Crafts reaction in nitrobenzene solution yields about 90 per cent, of the p-ketone and 10 per cent, of the a-ketone in carbon disulphide solution at — 15°, the proportions ore 65 per cent, of the a- and 35 per cent, of the p-isomer. With chlorobenzene ns the reaction medium, a high proportion of the a-ketone is also formed. Separation of the liquid a-isomer from the solid p-isomer in Such mixtures (which remain liquid at the ordinary temp>erature) is readily effected through the picrates the picrate of the liquid a-aceto compound is less soluble and the higher melting. 

In all its reactions the lone pair of thiazole is less reactive than that of pyridine. Table 1-61 shows three sets of physicochemical data that illustrate this difference. These are (1) the thermodynamic basicity, which is three orders of magnitude lower for thiazole than for pyridine (2) the enthalpy of reaction with BF3 in nitrobenzene solution, which is 10% lower for thiazole than for pyridine and (3) the specific rate of quaterni-zation by methyl iodide in acetone at 40°C, which is about 50% lower for... 

TABLE m-50. RATE CONSTANTS AND ACTD ATION PARAMETERS FOR THE REACTION OF 2-ALKYLTHl AZOLES WITH METHYL IODIDE IN NITROBENZENE (256)... 

TABLE in-52. KINETIC DATA FOR THE OUATERNI-ZATION OF 2- AND 4-ALKYLTHIAZOLES WITH METHYL IODIDE IN NITROBENZENE AT 25°C (256)... 

The quatemization of 16 2,4-dialkylthiazoles with methyl tosylate in nitrobenzene at 25 C has been studied (256) in order to examine the simultaneous influence of two substituents grouped around a reaction center (257). 

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