2-nitro-/>-xylene

Distler, Blecher Lopex Explosives were patented safety expls consisting of nitro-xylenes as chief constituents. The nitro compds had varying amts of cumol, mesitylene xylene nitro constituents mixed with AN, other nitrates or KClOg or metal oxides. For example, if 12 parts nitrated solvent naphtha are intimately mixed with 88 parts of AN, a very insensitive expl is produced, which is unaffected by either shock or percussion which does not explode at 200° or in an open flame, but which has an extremely powerful shattering effect when suitably detonated Ref Colver (1918), p259... 

Russkii Koktel (Russian Cocktail). An incendiary liquid used during WWII against tanks, [t consisted of K chlorate 80 Nitrobenzene (or Nitrotoluene, or Nitro-xylene) 20%... 

Of the three isomeric xylenes, each of which yields nitro products, it is the meta-xylene or i-3-di-methyl benzene which is most easily nitrated. The number of isomeric nitro xylenes possible has been previously explained (pp. 472 and 482). In the case of meta-xylene three such nitro compounds are possible but only one is readily obtained. It is I-3-di-methyl 4-nitro benzene that is, the nitro group enters the ring ortho to one methyl group and para to the other. This is just what we should expect from the influence of the methyl group upon subsequent substitution (p. 506). The nitro xylenes are not so important as nitro benzene or the nitro toluenes, but have some use in dyestuff manufacture. 

Nitro-m-xylene 2-Nitro-p-xylene 2-Nitro-p-cymene (4) Nitromesitylene... 

Cydopentane reagents used in synthesis are usually derived from cyclopentanone (R.A. Ellison, 1973). Classically they are made by base-catalyzed intramolecular aldol or ester condensations (see also p. 55). An important example is 2-methylcydopentane-l,3-dione. It is synthesized by intramolecular acylation of diethyl propionylsucdnate dianion followed by saponification and decarboxylation. This cyclization only worked with potassium t-butoxide in boiling xylene (R. Bucourt, 1965). Faster routes to this diketone start with succinic acid or its anhydride. A Friedel-Crafts acylation with 2-acetoxy-2-butene in nitrobenzene or with pro-pionyl chloride in nitromethane leads to acylated adducts, which are deacylated in aqueous acids (V.J. Grenda, 1967 L.E. Schick, 1969). A new promising route to substituted cyclopent-2-enones makes use of intermediate 5-nitro-l,3-diones (D. Seebach, 1977). 

A solution of trifluoroacetic acid in toluene was found to be advantageous for cydization of pyruvate hydrazoncs having nitro substituents[4]. p-Toluene-sulfonic acid or Amberlyst-15 in toluene has also been found to give excellent results in preparation of indole-2-carboxylale esters from pyruvate hydra-zoiies[5,6J. Acidic zeolite catalysts have been used with xylene as a solvent to convert phenylhydraziiies and ketones to indoles both in one-flask procedures and in a flow-through reactor[7]. 

Cohn points out that position isomerism is of the greatest importance as regards the odours of isomerides, this is strikingly instanced in the case of the tri-nitro tertiary butyl xylenes since the only one possessing the powerful musk odour is that in which the nitro groups are situated each in the meta position to the two others again the ortho-amido-benzaldehyde has a strong odour but the meta and para isomerides are odourless. 

The ester 3 (R1 = H, R2 = (CH2)3NMe2 23 g. 67 mmol), obtained by catalytic hydrogenation of the corresponding nitro compound, was heated in refluxing xylene (700 mL) for 15 h. The solvent was removed under reduced pressure and the residue was dissolved in 1 M HOAc and charcoal was added. The filtered solution was made alkaline with coned NH3 and the resulting precipitate was extracted with CHC1V The extract was washed with H20, dried and evaporated in vacuo, leaving the product yield 9.25 g (47%) mp 151-152 C. 

C. MEDINA. The crude methylenedi(nitro-formamide) is pressed dry on the filter, stirred into lOSml of formic acid, and the paste allowed to stand overnight. The next day the soln is filtered thru an acid-proof flit, the formic acid and w removed by codistn with xylene, and the crude MEDINA, which seps as a sand, filtered and dried over paraffin and NaOH in a vacuum yield 80—100% based on methylene diform-amide, mp 98—103°. The crude MEDINA is recrystd from 2-nitropropane or et chloride iso-Pr ale 9 1, mp 104-059 (Ref 11, p 54). This prepn is also covered in Ref 20... 

OB to C02 —85.04%, needles from glac AcOH, mp 262—63° (decomp). Sol in glac AcOH, acet, dioxane py si sol in benz, toluene, xylene amyl ale. Prepn from l-nitro-2-. me thy lnaphthalene by nitration using mixed acids of nitric (d 1.52g/cc), sulfuric (d 1.84 g/cc) oleum (20—25% SO5 free), and heating for one hour at 80° on a water bath. Two other isomers which do not decompose are prepd simultaneously viz, mp (I) 230° ... 

Toxicity. Picric Acid is more toxic than the nitro derivatives of toluene, xylene or naphthalene. It is, however, much less toxic than nitro derivatives of benzene... 

Nitro-l,2-benzenediamine (152) and chloroacetonitrile (153) gave 6-nitro-3,4-dihydro-2-quinoxalinamine (154), apparently without 7-nitro isomer (Et3N, p-xylene, reflux, 6 h 47%). ... 

Whereas secondary nitroalkanes such as 1-nitrocyclohexane 1766 are reduced to the corresponding oximes, for example 1767 [24], primary nitro compounds such as a-nitro-o-xylene 1768 or unsaturated nitro compounds such as 1770 are transformed into nitriles such as 1769 and 1771 [24] (Scheme 12.6). 

Schrader prepared the ester (38) in 60% yield by reaction of sodium p-nitrophenate with diethyl chlorophosphate, using xylene as solvent for the reaction. He made it, but in lower yields, from p-nitrophenol and diethyl chlorophosphate, using, respectively, pyridine and sodium cyanide as acceptors for hydrogen chloride. Schrader also prepared it in 96% yield by nitrating diethyl phenyl phosphate at 0° C. or below. Under the conditions he used, Schrader claims that the nitro group is directed to the para position. No yield is given for the diethyl phenyl phosphate, which he presumably made from sodium phenate and diethyl chlorophosphate. Diethyl chlorophosphate may be prepared in high yield (30) from diethyl phosphite and chlorine. 

Pyrazoles were synthesized in the authors laboratory by Le Blanc et al. from the epoxy-ketone as already stated in Sect. 3.1.1a, Scheme 35 [80]. The synthetic strategy employed by Le Blanc et al. [80] was based upon that the strategy published by Bhat et al. [81] who also described the synthesis of pyrazoles but did not report cytotoxic evaluation on the synthesized compounds. Scheme 48 shows the synthesis of the most active compound (178). Dissolution of the epoxide (179) with a xylenes followed by treatment with p-toluenesulfonic acid and hydrazine hydrate produced the pure nitro-pyrazole 180 in good yield (60%). Catalytic hydrogenation with palladium on activated carbon allowed the amino-pyrazole (178) to be obtained in a pure form. This synthesis allowed relatively large numbers of compounds to be produced as the crude product was sufficiently pure. Yield, reaction time, and purification compared to reported approaches were improved [50, 61, and 81]. Cytotoxicity of these pyrazole analogs was disappointing. The planarity of these compounds may account for this, as CA-4, 7 is a twisted molecule. 

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