Nitro-derivative

Trichloronitromethane, CC NO, is decomposed by fuming sulfuric acid (containing 20% SO3) at 100 C into phosgene (73% yield) and nitrosyl chloride [1825]  

The experimental conditions in this procedure resemble those described for the formation of phosgene from CCl. The photochemical decomposition is discussed in Section 5.2.5. 

The use of Lewis acids has no stereochemical consequence on the course of the reaction. Therefore, the formation of a chelated species such as A (Fig. 5), involving the oxygens of the sulfinyl and nitro groups, was disregarded by the authors (it would be consistent with an inversion of the 7r-facial selectivity). 

They suggest another chelation, involving the two oxygens at the nitro group (B in Fig. 5) to rationalize the marked rate acceleration produced by addition of the Lewis acid, so maintaining the stereochemical preferences. 

Chapman etal, US Patent 6,562,985 (May 13, 2003) Assignee United States of America as Represented by the Secretary of The Navy 

To a stirred solution of 1,3-diamine-2-hydroxy propane (58.8 mmol) and K2CO3 (155.8 mmol) dissolved in 100 ml of water at 0°C was added dropwise p-nosyl chloride (132.1 mmol) dissolved in 60 ml THE. Thereafter the solution was stirred at ambient temperature overnight and then concentrated. The product was purified by chromatography on silica using EtOAc/hexanes, 1 1, re-crystallized in acetone/hexanes, and isolated in 95% yield, mp = 210-212 °C (sub). H- and H-NMR data supplied. 

The product from Step 1 (22.35 mmol) was dissolved in 300 ml acetone and oxidized using a mixture of Cr03 (58.2 mmol) in 15 ml water containing 6 ml 98% H2SO4. After the addition was completed the mixture stirred overnight and was then poured into water. The resulting solid was filtered, washed, and isolated as a white solid in 91% yield, mp = 212 °C (dec.). H- and C-NMR data supplied. 

The product from Step 2 (26.83 mmol), ethylene glycol (97.63 mmol) and p-toluenesulfonic acid monohydrate ( 0.5g) dissolved in 200 ml toluene were heated under reflux 3 days using a Dean-Stark trap to remove water. After cooling, the solid was washed, re-crystallized in DMF, and the product obtained in 90% yield, mp = 237 °C. H- and C-NMR data supplied. 

Hexahydro-l,5-bis(4-nitrobenzenesulfonyl)-l,5-diazocine-3-ethylene ketal-7-methylene 

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Naphihalene-2-sulphonic acid crystallizes with 3H2O, m.p. 83 C. It is also used for the preparation of nitro-derivatives. 

Bromobenzene, iodobenzene and benzyl chloride behave somewhat similarly. The />-nitro-derivatives of the first two compounds frequently crystallise out even before pouring into water p-nitrobenzyl chloride usually remains as an oil for several minutes before solidifying. 

Nitroamlines. Acetyl derivatives (p. 388), Benzoyl derivatives (p. 388). Diamines. Diacet> l derivatives (p. 388), Dibenzoyl derivatives (p. 388). Halogeno-hydrocarbons, a-Naphthyl ethers (from reactive halogen compounds, p. 391, and their Picratcs, p. 394), Nitro-derivatives (p.39i). Carboxylic acid (if oxidisable side chain) (p. 393). 

Fif rea given before the M.ps. of Nitro derivatives indicate position of nitro groups. 

Nitro derivatives. No general experimental details for the preparation of nitro derivatives can be given, as the ease of nitration and the product formed frequently depend upon the exact experimental conditions. Moreover, some organic compounds react violently so that nitrations should always be conducted on a small scale. The derivatives already described are usually more satisfactory for this reason the nitro derivatives have been omitted from Table IV,9. 

Oxidation of side chains. Aromatic nitro compounds that contain a side chain (e.g., nitro derivatives of alkyl benzenes) may be oxidised to the corresponding acids either by alkahne potassium permanganate (Section IV,9, 6) or, preferably, with a sodium dichromate - sulphuric acid mixture in which medium the nitro compound is more soluble. 

Experimental requirements for the isolation of these nitramino derivatives are developed in Ref. 87. They rearrange easily to ring nitro-substituted isomers (see Section V.6). In the 2-aminothiazole series, nitration may proceed through direct electrophilic substitution competing with rearrangement of nitramino derivatives. Dickey et al. have shown that the rearrangement proceeds rapidly in 96% sulfuric acid at 2(fC, but in 85% sulfuric add it is very slow so. according the concentration of add various mechanisms can participate in the formation of the 5-nitro derivative. 

The 2-benzamido 4-aryl(alkyl)selenazoles (96) form the corresponding 5-nitro derivatives under mild conditions using the nitrate-sulfuric acid method (Scheme 31). The nitro compounds are well-defined, ciy s-talline compounds. They may be most favorably obtained by dissolving the 2-benzamidoselenazoles in acetone and adding concentrated nitric... 

However, prior protective acetylation of the amino group leads to a good yield of the 5-nitro compound [2-acetamido-4-methyl-5-nitroselenazole, m.p. 185 C (19)j. Similarly. 2-diethylamino-4-methy)-selenazole with nitric acid gives the. 5-nitro derivative [vellow needles, m.p. 93°C (26)],... 

Also present but not essential in permanent hair colorants are nitro dyes which dye hair without oxidation. These dyes, nitro derivatives of aminophenols and benzenediamines, impart yellow, orange, or red tones. Although they have good tinctorial value, they are not as colorfast as the oxidative dyes. They also are used in semipermanent hair colorants. 

Nitration of aromatic amines with urea nitrate in sulfuric acid is reported to yield the -nitro derivative exclusively (44). When the para position is blocked, the meta product is obtained in excellent yield. 

Although this reduction is more expensive than the Bnchamp reduction, it is used to manufacture aromatic amines which are too sensitive to be made by other methods. Such processes are used extensively where selectivity is required such as in the preparation of nitro amines from dinitro compounds, the reduction of nitrophenol and nitroanthraquinones, and the preparation of aminoazo compounds from the corresponding nitro derivatives. Amines are also formed under the conditions of the Zinin reduction from aromatic nitroso and azo compounds. 

Amino-4-nitropheno1 is produced commercially by the partial reduction of 2,4-dinitrophenol This reduction may be achieved electrolyticaHy using vanadium (159) or chemically with polysulftde, sodium hydrosulftde, or hydrazine and copper (160). Alternatively, 2-acetamidophenol or 2-methylbenzoxazole may be nitrated in sulfuric acid to yield a mixture of 4- and 5-nitro derivatives that are then separated and hydrolyzed with sodium hydroxide (161). 

Nitro and Nitroso Dyes. These dyes are now of only minor commercial importance, but are of interest for their smaU molecular stmctures. The early nitro dyes were acid dyes used for dyeing the natural animal fibers such as wool and sUk. They were nitro derivatives of phenols, eg, picric acid [88-89-1] (73) (Cl 10305), or naphthols, eg. Cl Acid YeUow 1 [846-70-8] (74) (Cl 10316). 

The 3-, 4-, 5- and 6-positions in the pyridazine nucleus are electron deficient due to the negative mesomeric effect of the nitrogen atoms. Therefore, electrophilic substitution in pyridazines is difficult even in the presence of one or two electron-donating groups. The first reported example is nitration of 4-amino-3,6-dimethoxypyridazine to yield the corresponding 5-nitro derivative. Nitration of 3-methoxy-5-methylpyridazine gives the 6-nitro-,... 

Pyridazine 1-oxides substituted at position 3 or positions 3 and 6 afford the corresponding 5-nitro derivatives. A methyl group at position 6 (a with respect to the iV-oxide group) is frequently converted into the cyano group, and a methoxy group at position 6 is demethy-lated by benzoyl chloride/silver nitrate. For example, 3-substituted 6-methylpyridazine 1-oxides give the 5-nitro derivatives (96) and the 6-cyano-5-nitro derivatives (97), whereas... 

Dimethylpyridazine 1,2-dioxide gives the 4-nitro derivative in good yield with nitric acid, while with benzoyl nitrate the yield is considerably lower. 

Cinnolin-4(lF/)-one and its 6-chloro, 6-bromo, 6-nitro and 8-nitro derivatives react with sulfuryl chloride or bromine in acetic acid to give the corresponding 3-halo derivatives in about 20% yields. lodination of 8-hydroxycinnolin-4(lF/)-one with a mixture of potassium iodide and potassium iodate gives the 5,7-diiodo derivative the 6,8-diiodo derivative is formed from 5-hydroxycinnolin-4(lF/)-one. 

Nitration of cinnoline 2-oxide takes a different course. With nitric and sulfuric acids or with potassium nitrate and sulfuric acid a mixture of 8-nitrocinnoline 2-oxide, 6-nitrocinno-line 2-oxide and 5-nitrocinnoline 2-oxide is obtained, while with benzoyl nitrate in chloroform only a low yield (1.5%) of the 5-nitro derivative is obtained. 

Upon nitration of phthalazines a nitro group is introduced only into the carbocyclic ring. Side reactions occur frequently. For example, nitration of phthalazine or its 1-methyl analog with potassium nitrate in concentrated sulfuric acid gives the 5-nitro derivative (100) as the main product together with 5-nitrophthalazin-l(2H)-one (101) as a by-producf (Scheme 27). 

Hydroxyaminopyridazine 1-oxides are usually formed by catalytic hydrogenation of the corresponding nitro derivatives over palladium-charcoal in methanol, provided that the reaction is stopped after absorption of two moles of hydrogen. 3-Hydroxyaminopyridazine 1-oxide and 6-amino-4-hydroxyamino-3-methoxypyridazine 1-oxide are prepared in this way, while 5-hydroxyamino-3-methylpyridazine 2-oxide and 5-hydroxyamino-6-methoxy-3-methylpyridazine 2-oxide are obtained by chemical reduction of the corresponding nitro compounds with phenylhydrazine. 

When activating substituents are present in the benzenoid ring, substitution usually becomes more facile and occurs in accordance with predictions based on simple valence bond theory. When activating substituents are present in the heterocyclic ring the situation varies depending upon reaction conditions thus, nitration of 2(177)-quinoxalinone in acetic acid yields 7-nitro-2(177)-quinoxalinone (21) whereas nitration with mixed acid yields the 6-nitro derivative (22). The difference in products probably reflects a difference in the species being nitrated neutral 2(177)-quinoxalinone in acetic acid and the diprotonated species (23) in mixed acids. 

Indole can be nitrated with benzoyl nitrate at low temperatures to give 3-nitroindole. More vigorous conditions can be used for the nitration of 2-methylindole because of its resistance to acid-catalyzed polymerization. In nitric acid alone it is converted into the 3-nitro derivative, but in a mixture of concentrated nitric and sulfuric acids 2-methyl-5-nitroindole (47) is formed. In sulfuric acid, 2-methylindole is completely protonated. Thus it is probable that it is the conjugate acid which is undergoing nitration. 3,3-Dialkyl-3H-indolium salts similarly nitrate at the 5-position. The para directing ability of the immonium group in a benzenoid context is illustrated by the para nitration of the conjugate acid of benzylideneaniline (48). 

Nitration of benzo[6]thiophene (HNOs/AcOH) yields mainly the 3-nitro derivative. Under these conditions the /3 to a ratio of substitution is approximately 5 1, which is... 

Pyrazoles can undergo nitration at several positions 4-bromo-l-methylpyrazole yields the 3,5-dinitro product. 1-Methylpyrazole 2-oxide yields the 5-nitro derivative. 

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