Nitromethane, Bromo

For the nine substituents m- andp-methyl, p-fluoro, m- and p-chloro, m- and p-bromo, and m- and p-iodo, using the results for nitration carried out at 25 °C in nitromethane or acetic anhydride - (see tables 9.1, 9.5), a plot of logjoA/ j against cr+ produced a substituent constant p = —6-53 with a standard deviation from the regression line i = 0-335, 2 correlation coefficient c = 0-975. Inclusion of... 

This class was first reported in 1924 and was formed 62HC(17)l) by cyclization of a-bromo-/3-aryl-y-nitroketones. The direct synthesis by oxygenation of 2-isoxazolines has not been reported. To date only 3-substituted derivatives have been prepared. Aryl-nitromethanes react with nitrostilbene to form isoxazoline A-oxide by a nitrile ion displacement (Scheme 138) <62HC(17)1, 68TL3375). 

A kinetic isotope effect, kH/kD = 1.4, has been observed in the bromination of 3-bromo-l,2,4,5-tetramethylbenzene and its 6-deuterated isomer by bromine in nitromethane at 30 °C, and this has been attributed to steric hindrance to the electrophile causing kLx to become significant relative to k 2 (see p. 8)268. A more extensive subsequent investigation304 of the isotope effects obtained for reaction in acetic acid and in nitromethane (in parentheses) revealed the following values mesitylene, 1.1 pentamethylbenzene 1.2 3-methoxy-1,2,4,5-tetramethyl-benzene 1.5 5-t-butyl-1,2,3-trimethylbenzene 1.6 (2.7) 3-bromo-1,2,4,5-tetra-methylbenzene 1.4 and for 1,3,5-tri-f-butylbenzene in acetic acid-dioxan, with silver ion catalyst, kH/kD = 3.6. All of these isotope effects are obtained with hindered compounds, and the larger the steric hindrance, the greater the isotope... 

Nitromethane, cyanomethyl phenyl sulfbne 78a, and benzyl cyanoacetate 78b underwent the asymmetric cydopropanation with 2-bromo-2-cydo-... 

The nature of the solvent also determines the chemoselective outcome in the reaction products. Products arising from the incorporation of one solvent molecule are formed (besides dibromides) in alcohols, acetic acid and acetonitrile (Id-e), whereas dibromo derivatives are formed exclusively in chlorinated solvents, nitromethane and in ionic liquids. (9) Chemoselectivity depends on the relative nucleophilicity of the solvent and the counterion, although it is affected also by other phenomena (ion pairing, and ion dissociation) in methanol the addition process gives quasi-exclusively bromo-methoxy adducts, whereas in acetic acid dibromides are the main products, formed in addition to smaller amounts of the bromo-acetoxy derivatives. (70)... 

Bromo-4,5-methylenedioxy-B-nitrostyrene. A solution of 64 g bromopiperonal, 65 g nitromethane (or analog), and 30 g of NH4OAC in 400 ml of AcOH, is heated to reflux for 2 hours. Cool and pour the mixture into 1 liter of water. This will precipitate a crystal solid that is removed by filtration and recrystallized from CHCf-EtOH (50% by volume) to give the product. Yield 55 g, mp 160-161°. 

The 1-nitroindolizine (113) was formed in a reaction of the pyridinium salt (112) with nitromethane/triethylamine in methanol. Successive treatment of the quinolizinium bromide (114) with piperidine and an a-bromo ketone yielded (115), which was cyclized on an alumina column (Scheme 16) (72TL2607). 

SYNTHESIS To a vigorously stirred suspension of 2.1 g 4-bromo-2,5-dimethoxy-B-nitrostyrene [from 4-bromo-2,5-dimethoxybenzaldehyde and nitromethane in acetic acid with ammonium acetate as a catalyst, mp 157-158 °C, anal. (C 0H]0BrNO )... 

Photostimulated, S r k 1 reactions of carbanion nucleophiles in DMSO have been used to advantage in C—C bond formation (Scheme 1).25-27 Thus, good yields of substitution products have been obtained from neopentyl iodide on reaction with enolates of acetophenone and anthrone, but not with the conjugate base of acetone or nitromethane (unless used in conjunction, whereby the former acts as an entrainment agent).25 1,3-Diiodoadamantane forms an intermediate 1-iodo mono substitution product on reaction with potassium enolates of acetophenone and pinacolone and with the anion of nitromethane subsequent fragmentation of the intermediate gives derivatives of 7-methylidenebicyclo[3.3.1]nonene. Reactions of 1,3-dibromo- and 1-bromo-3-chloro-adamantane are less effective.26... 

Chloro-7-bromo-l,2,3,5-tetrahydroimidazo[2,l-b]quinazolin-2-one was produced next way to a solution of 1.30 g (8 mmole) of anhydrous ferric chloride in 30 ml of nitromethane was added 1.30 g (5 mmole) of solid 6-chloro-l,2,3,5-tetrahydroimidazo[2,l-b]quinazolin-2-one and 0.80 g (5 mmole) of bromine. The system was stoppered, warmed to 50°C in an oil bath overnight, cooled to room temperature and the solvent removed in vacuo. The resulting solid was suspended in water (50 ml), the mixture was made basic (pH = 10) with sodium bicarbonate and stirred at home temperature for 20 min. The solid was filtered under suction, washed with water, then isopropyl alcohol and dried yielding 1.19 g of 6-chloro-7-bromo-l,2,3,5-tetrahydroimidazo[2,l-b]quinazolin-2-one (78% yield). Purification was effected by formation of the hydrochloride salt (mp 275°C) from acetonitrile. 

The enantio-determining step of nucleophilic additions to a-bromo-a,y -unsaturated ketones is mechanistically similar to those of nucleophilic epoxidations of enones, and asymmetry has also been induced in these processes using chiral phase-transfer catalysts [20]. The addition of the enolate of benzyl a-cyanoacetate to the enone 31, catalysed by the chiral ammonium salt 32, was highly diastereoselective and gave the cyclopropane 33 in 83% ee (Scheme 12). Good enantiomeric excesses have also been observed in reactions involving the anions of nitromethane and an a-cyanosulfone [20]. 

Monobromination of 2,4-dimethylbenzodiazepine in a mixture of acetic acid and nitromethane provided a deep blue salt, which was designated as 3-bromo-2,4-dimethylbenzodiazepinium bromide (62JPR156). However, an alternative product, which was brown-yellow, was obtained from the reaction of o-phenylenediamine with 2-bromo-l,l,3,3-tetraethoxypropane (62JPR156). 

J-Chloro-a,/ -unsaturated aldehydes react with sodium sulfide and bromo-nitromethane to give 2-nitrothiophenes [Eq. (6)].24... 

A number of a-nitro carboxylic acids are easily dicarboxylated to furnish nitro compounds. The synthesis of nitromethane in this manner is a classical example (38%). Nitroethane and higher homologs have been similarly prepared from the a-bromo acids and sodium nitrite. Another example is found in the synthesis of phenylnitromethane. Treatment of benzyl cyanide with methyl nitrate in the presence of sodium ethoxide gives the sodium salt of the aci-niao compound, which is then hydrolyzed and decarboxylated. ... 

The stereochemistry of the 6/8,7/8-adduct (8) from the corresponding 6-chloro-4,6-dien-3-one and nitromethane has been established by X-ray analysis. The la,2a -adduct (9) formed from a 2-bromo-l,4,6-trien-3-one has been similarly characterized. ... 

BROMO BUTANE or n-BROMOBUTANE (109-65-9) Forms explosive mixture with air (flash point 65°F/18°C). Violent reaction with strong oxidizers, strong acids. Incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, glycols, isocyanates, ketones, maleic anhydride, nitrates, nitromethane, phenols, vinyl acetate. May accumulate static electrical charges may cause ignition of its vapors. 

QUECKSILBER (German) (7439-97-6) Violent reaction with alkali metals, aluminum, acetylenic compounds, azides, boron phosphodi iodide (vapor explodes), bromine, 3-bromo-propyne, chlorine, chlorine dioxide, ethylene oxide, lithium, metals, methyl silane (when shaken in air), nitromethane, peroxyformic acid, potassium, propargyl hromide, rubidium, sodium, sodium carbide. Forms sensitive explosive products with acetylene, ammonia (anhydrous), chlorine, picric acid. Increases the explosive sensitivity of methyl azide. Mixtures with hot sulfuric acid can be explosive. Incompatible with calcium, sodium acetylide, nitric acid. Reacts with copper, silver, and many other metals (except iron), forming amalgams. 

Toluenesulfonyl perchlorate (which is formed from 5-10% solutions of /Koluenesulfonyl bromide and silver perchlorate in nitromethane at 0°) is the strongest sulfonylating agent known.231 For instance, it sulfonylates the relatively unreactive halobenzenes in satisfactory yield at room temperature / -bromo- and / -chloro-phenyl p-tolyl sulfone were obtained in 66.5% and 63% yield, respectively 231... 

---