5.5- dimethyl-3- 4-nitro-3-

The similarity of their rate profiles, and the similarity of their rate constants for nitration at a particular temperature and acidity show that 4-pyridone, i-methyl-4-pyridone, and 4-methoxypyridine are all nitrated as their cations down to about 85 % sulphuric acid. The same is true of 2-methoxy-3-methylpyridine. In contrast, 3- and 5-methyl-2-pyridone, i,5-dimethyl-2-pyridone and 3-nitro-4-pyridone all react... 

Davies and Warren" found that when 1,4-dimethylnaphthalene was treated with nitric acid in acetic anhydride, and the mixture was quenched after 34 hr, a pale yellow solid with an ultraviolet spectrum similar to that of a-nitro-naphthalene was produced. However, if the mixture was allowed to stand for 5 days, the product was i-methyl-4 nitromethylnaphthalene, in agreement with earlier findings. Davies and Warren suggested that the intermediate was 1,4-dimethyl-5 nitronaphthalene, which underwent acid catalysed rearrangement to the final product. Robinson pointed out that this is improbable, and suggested an alternative structure (iv) for the intermediate, together with a scheme for its formation from an adduct (ill) (analogous to l above) and its subsequent decomposition to the observed product. 

The telomer obtained from the nitromethane 65 is a good building block for civetonedicarboxylic acid. The nitro group was converted into a ketone, and the terminal alkenes into carboxylic acids. The acyloin condensation of protected dimethyl dvetonedicarboxylate (141) afforded the 17-membered acyloin 142, which was modified to introduce a triple bond 143. Finally, the triple bond was reduced to give civetone (144)[120). 

Reduction of 2.4-dimethyl-5-nitrothiazole with activated iron gives a product that after acetylation yields 25% 2.4-dimethyl-5-acetamido-thiazole (58). The reduction of 2-methyl 5-nitrothiazole is also reported (351 to give a mixture of products. The nitro group of 2-acetylhydrazino-5-nitrothiazole is reduced by TiCl in hydrochloric acid or by Zn in acetic acid (591. 

In the examples, a nitro group is substituted for a hydrogen atom, and water is a by-product. Nitro groups may, however, be substituted for other atoms or groups of atoms. In Victor Meyer reactions which use silver nitrite, the nitro group replaces a hahde atom, eg, I or Br. In a modification of this method, sodium nitrite dissolved in dimethyl formamide or other suitable solvent is used instead of silver nitrite (1). Nitro compounds can also be produced by addition reactions, eg, the reaction of nitric acid or nitrogen dioxide with unsaturated compounds such as olefins or acetylenes. 

Ttinitroparaffins can be prepared from 1,1-dinitroparaffins by electrolytic nitration, ie, electrolysis in aqueous caustic sodium nitrate solution (57). Secondary nitroparaffins dimerize on electrolytic oxidation (58) for example, 2-nitropropane yields 2,3-dimethyl-2,3-dinitrobutane, as well as some 2,2-dinitropropane. Addition of sodium nitrate to the anolyte favors formation of the former. The oxidation of salts of i7k-2-nitropropane with either cationic or anionic oxidants generally gives both 2,2-dinitropropane and acetone (59) with ammonium peroxysulfate, for example, these products are formed in 53 and 14% yields, respectively. Ozone oxidation of nitroso groups gives nitro compounds 2-nitroso-2-nitropropane [5275-46-7] (propylpseudonitrole), for example, yields 2,2-dinitropropane (60). 

I itro-DisplacementPolymerization. The facile nucleophilic displacement of a nitro group on a phthalimide by an oxyanion has been used to prepare polyetherimides by heating bisphenoxides with bisnitrophthalimides (91). For example with 4,4 -dinitro monomers, a polymer with the Ultem backbone is prepared as follows (92). Because of the high reactivity of the nitro phthalimides, the polymerkation can be carried out at temperatures below 75°C. Relative reactivities are nitro compounds over halogens, Ai-aryl imides over A/-alkyl imides, and 3-substituents over 4-substituents. Solvents are usually dipolar aprotic Hquids such as dimethyl sulfoxide, and sometimes an aromatic Hquid is used, in addition. 

Solvent for Displacement Reactions. As the most polar of the common aprotic solvents, DMSO is a favored solvent for displacement reactions because of its high dielectric constant and because anions are less solvated in it (87). Rates for these reactions are sometimes a thousand times faster in DMSO than in alcohols. Suitable nucleophiles include acetyUde ion, alkoxide ion, hydroxide ion, azide ion, carbanions, carboxylate ions, cyanide ion, hahde ions, mercaptide ions, phenoxide ions, nitrite ions, and thiocyanate ions (31). Rates of displacement by amides or amines are also greater in DMSO than in alcohol or aqueous solutions. Dimethyl sulfoxide is used as the reaction solvent in the manufacture of high performance, polyaryl ether polymers by reaction of bis(4,4 -chlorophenyl) sulfone with the disodium salts of dihydroxyphenols, eg, bisphenol A or 4,4 -sulfonylbisphenol (88). These and related reactions are made more economical by efficient recycling of DMSO (89). Nucleophilic displacement of activated aromatic nitro groups with aryloxy anion in DMSO is a versatile and useful reaction for the synthesis of aromatic ethers and polyethers (90). 

When large groups, such as phenyl, bromo, ethoxycarbonyl or nitro are attached at position 3, the principal products are l-alkylcinnolin-4(l/f)-ones. Cyanoethylation and acetylation of cinnolin-4(l/f)-one takes place exclusively at N-1. Phthalazin-l(2/f)-ones give 2-substituted derivatives on alkylation and acylation. Alkylation of 4-hydroxyphthala2in-l(2/f)-one with an equimolar amount of primary halide in the presence of a base leads to 2-alkyl-4-hydroxyphthalazin-l(2/f)-one and further alkylation results in the formation of 4-alkoxy-2-alkylphthalazinone. Methylation of 4-hydroxy-2-methyl-phthalazinone with dimethyl sulfate in aqueous alkali gives a mixture of 4-methoxy-2-methylphthalazin-l(2/f)-one and 2,3-dimethylphthalazine-l,4(2//,3//)-dione, whereas methylation of 4-methoxyphthalazin-l(2/f)-one under similar conditions affords only 4-methoxy-2-methylphthalazinone. 

Dimethylpyrazole 1.4- Dimethyl-3-nitropyrazole The attack at the 3- and 5-positions occurs on the free base. Standard rates 1,4-dimethylpyrazole (attack at the 3-position), log /co = 3.55, l,4-dimethyl-3-nitropyrazole (attack at the 5-position), log /c = -4.73 (deactivating effect of the nitro group) 75JCS(P2)1632... 

Nitration of a series of methyl-1,2-benzisoxazoles was studied by Tahkar and Bhawal using fuming nitric acid and sulfuric acid in acetic acid at 100 °C. 3-Methyl-1,2-benzisoxazole gave a mixture of 5-nitro- and 5,7-dinitro-3-methyl-l,2-benzisoxazole, with the 5-nitro isomer predominant. The product obtained from 3,5-dimethyl-1,2-benzisoxazole was the 4-nitro derivative and not the 7-nitro compound as proposed by Lindemann (26LA(449)63). The synthesis of the 7-nitro compound by an alternative method was used as structural proof. Two products were obtained from 3,6-dimethyl-l,2-benzisoxazole and these were the 5-nitro and 5,7-dinitro derivatives. 3,7-Dimethyl-l,2-benzisoxazole was converted into the 5-nitro derivative (Scheme 25) (77lJC(B)l06l). 

Reduction of 3,5-dimethyl-7-nitro-l,2-benzisoxazole with SnCU and HCl produced both the 7-amino compound and a 4-chloro-7-amino derivative (Scheme 28) (67AHC(8)277). 

Furan-3-carboxamide, N,fV-dimethyl-AG, 4, 34 <76JOC3591, 77TI337) Furan-2-carboxylate, 2-nitro-, ethyl ester UV, 4, 588 <50JA753>... 

Imidazole, 4-amino-1,2-dimethyl-5-nitro-pX , 5. 384 ... 

Imidazole, 4-methoxy-1,2-dimethyl-5-nitro-pKa, 5, 384 [Pg.28]

Benzimidazole, 2,6-dimethyl-4-nitro-alkylation, 5, 389-390 Benzimidazole, IV-ethyl-sensitizing dyes... 

H-Chromene, 7-methoxy-2,3-dimethyl-application, 3, 881 2H-Chromene, 2-methyl-mass spectra, 3, 603 2H-Chromene, 2-methyl-3-nitro-hydrogenation, 3, 673... 

Furoxans, diethyl-synthesis, 6, 423 Furoxans, dihalo-synthesis, 6, 423 Furoxans, dimethyl-NMR, 6, 397 O NMR, 6, 398 Furoxans, diphenylring cleavage, 6, 404 synthesis, 6, 423 Furoxans, hydroxy-reactions, 6, 414 Furoxans, mercapto-reaotions, 6, 414 Furoxans, nitro-as explosives, 6, 426 reactions, 6, 413-414 reduction, 6, 423 Furoxans, phenyl-reactions... 

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