Aqueous hydrogen bromide

Unexpected formation of the oxoadamantane skeleton is observed during a series of transformations of the alkaloid lycopoline 153 lead tetraacetate oxidation of the alcohol (131) gives a 90% yield of the oxaadamantane (132), which is opened to 133 with boron trifluoride in acetic anhydride and re-cyclized to 132 with aqueous hydrogen bromide. 

The /-butyl group was removed from the A-2-substituted thiadiazol-3-one 143 in the presence of aqueous hydrogen bromide and TFA to afford (A ,.S )-2-amino-3-(3-hydroxy-1,2,5-thiadiazol-4-yl (propionic acid 42... 

Chloro-pentammino-cobaltic Bromide, [Co(NH3)5Cl]Bra, may be prepared from the chloride by treating a solution, which has been made slightly acid with dilute sulphuric acid, with well-cooled hydro-bromic acid. The precipitate formed is washed with dilute aqueous hydrogen bromide and then with alcohol. It may be formed also from the corresponding chloro-carbonate by precipitating from solution with concentrated hydrobromic acid. It crystallises in red oetahedra, and is more easily soluble than the chloride. 

Substituted indolizines have been hydrogenated to give 5,6,7,8-tetrahydroindolizines (72) using Raney nickel or a platinum catalyst at ambient temperature and pressure. The hydrogenation of the pyrrole ring of indolizine to (73) was successful with palladium on charcoal in aqueous hydrogen bromide. It is almost certain (see Section 3.08.3.1) that the 3H-indoIizinium cation is formed initially. 

Tetrahydropyrido[2,l-6][l,3]oxazine (29) afforded pyridinium bromide (30) on the action of aqueous hydrogen bromide, and no reaction occurred on treatment with NaBEL) in methanol [77JCS(P2)759]. Treatment of 3-oxo-2,3,7,8,9,10-hexahydro-l//-[l,3]oxazino[3,2-a]quinolinium chloride with ethanol yielded l-(2-carboxyethyl)-5,6,7,8-tetrahydro-2(l//)-quinolinone (69MI1). 

The octachlorodirhenate(2—) anion undergoes halogen exchange in methanol with aqueous hydrogen bromide at 60°C to form [( -C4H9)4N] 2Re2Br8 in 98% yield (63). Kinetic data have been obtained for the reverse reaction of HC1... 

The pyrrole ring of indolizine can be selectively reduced to 148 by catalytic hydrogenation using palladium/charcoal in aqueous hydrogen bromide.207... 

Whereas compound 7, as previously noted, is extremely sensitive to hydrolysis, it is actually rather difficult to cleave the NX)-acetal in the u-alkylated product 24. Use of aqueous hydrogen bromide as suggested by Setback 1 leads to only traces of product, although the desired result is achievable with dilute sulfuric acid... 

The treatment of dimethoxy derivative 451 (R = Me) with 48% aqueous hydrogen bromide at 80°C overnight yielded the trihydrobromide salt of dihydroxy derivative 451 (R = H) (87USP4695575). 

Iodine-catalysed hydroperoxidation of cyclic and acyclic ketones with aqueous hydrogen peroxide in acetonitrile is an efficient and eco-friendly method for the synthesis of gem -dihydroperoxides and the reaction is conducted in a neutral medium with a readily available low-cost oxidant and catalyst.218 Aryl benzyl selenoxides, particularly benzyl 3,5-bis(trifluoromethyl)phenyl selenoxide, are excellent catalysts for the epoxidation of alkenes and Baeyer-Villiger oxidation of aldehydes and ketones with hydrogen peroxide.219 Efficient, eco-friendly, and selective oxidation of secondary alcohols is achieved with hydrogen peroxide using aqueous hydrogen bromide as a catalyst. Other peroxides such as i-butyl hydroperoxide (TBHP), sodium... 

A mixture of 2-(di-n-propylamino)-5-methoxy-2,3-dihydro-lH-phenalene, (1.65 g 5.55 mmol), released from the hydrochloride salt, and 20 ml of 48% aqueous hydrogen bromide solution was heated for 15 min in an oil bath at 125°-130°C. The reaction mixture was evaporated, the residue was dissolved in a minimum amount of methanol, diethyl ether was added until the mixture became cloudy, and the mixture was filtered through a filter aid (CELITE) to remove some oily impurity. The filtrate was diluted with diethyl ether and seeded. There was obtained 1.28 g (63% yield) of the 2-(di-n-propylamino)-2,3-dihydro-IH-phenalen-5-ol hydrobromide, melting point 233°-234°C (dec.). 

Aqueous hydrogen bromide reacts with hydrogen peroxide to generate bromine in a rapid exothermic reaction (equation 42)301 ... 

The trihydrate, NiBr2.8H20, may he obtained by introducing finely divided nickel into bromine under water, or by dissolving nickel monoxide in aqueous hydrogen bromide. On concentrating the solution, the salt crystallises out in the form of deliquescent needles. 

As obtained in this way, platinic bromide is a dark powder, slightly soluble in water to a reddish brown solution which contains dihy-droxy-tetrabrom-platinic acid, H2PtBr4(OH)2. It is fairly soluble in a mixture of alcohol and water, and very soluble both in alcohol and in ether. On warming, however, these latter solutions become reduced, yielding a deposit of platinum black. Its solution in aqueous hydrogen bromide contains brom-platinic acid. 

Prepared by Robinson condensation of 2,3,5-trimethoxytetrahydro-furan 88, 49) (available from furan), the ketone XXIX gave with subsequent reduction the 6-methoxytropan-3a-ol (XXXII) (see Section III,B) which, in turn, was demethylated by aqueous hydrogen bromide (90%) to (+ )-tropan-3a,6j8-diol (XXXI). As a condensing agent, p-toluenesulfonic anhydride gave good yields of 3a,6a-oxido-tropane (XLVI). 

Complex tetra-, penta-, and hexa-bromides, together with salts containing the Sb2Br9 ion, are the products when SbBr3 and amine hydrobromides react in aqueous hydrogen bromide.733... 

Derivation High yields of nonyl bromide are obtained by passing hydrogen bromide into the alcohol while heating or by refluxing with aqueous hydrogen bromide in the presence of an acid catalyst. 

Another kind of intervention in the anhydrohexose aldose equilibrium has been described for l,6-anhydro-/3-D-gulopyranose. The action of 40% aqueous hydrogen bromide and bromine at 80° causes simultaneous hydrolysis and oxidation to D-gulono-1,4-lactone.122... 

When treatment of humulene with mercuric nitrate is followed by addition of aqueous hydrogen bromide a mixture of two products is isolated, one of them having lost the hydroxyl group at C-10, after elimination of water, to give the allylic ether 566. The tricyclic ethers 2, 3 and 4 are precursors in pentalene, pentalenic acid and hvdroxypentalene25 - 27 syntheses, as well as in the syntheses of sterpurene67 and hirsutene68. 

CAS/DOT IDENTIFICATION 10035-10-6/UN1048 (anhydrous), UN 1788 (solu-SYNONYMS anhydrous hydrogen bromide, aqueous hydrogen bromide, hydrobromic... 

A reaction occurs when hydrosulfuric acid (H2S) is mixed with an aqueous solution of iron(III) bromide. The reaction produces solid iron(III) sulfide and aqueous hydrogen bromide. Write the chemical and net ionic equations for the reaction. 

Synonyms/Trade Names Anhydrous hydrogen bromide Aqueous hydrogen bromide (i.e., Hydrobromic acid)... 

Hudroxuazulene has been prepared from 2-mcthoxyazulcnc by reaction with aqueous hydrogen bromide ]1.S0. This liydroxyazulcue which is stable in air, exists as an alcohol in methanol Init in chloroform or water it exists rather in a keto-form jl.SO], t.r. 

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