Ether hydrobromic

Synonyms AI3-04462 Bromic ether Bromoethane BRN 1209224 CCRIS 2504 EB EINECS 200-825-8 Halon 2001 Hydrobromic ether Monobromoethane NCI-C55481 NSC 8824 UN 1891. 

Synonyms Bromoethane hydrobromic ether bromic ether... 

SYNS BROMIC ETHER BROMOETHANE BROMURE d ETHYLE ETYLU BROMEK (POLISH) HALON 2001 HYDROBROMIC ETHER MONOBROMOETHANE NCI-C55481... 

HYDROBROMIC ACID see HHJOOO HYDROBROMIC ACID SOLUTION, >49% hydrobromic acid (UN 1788) (DOT) see HHJOOO HYDROBROMIC ACID SOLUTION, not >49% hydrobromic acid (UN 1788) (DOT) see HHJOOO HYDROBROMIC ETHER see EGV400 HYDROCARBON GAS see HHJ500 HYDROCARBON GASES, COMPRESSED, N.O.S. (UN... 

Synonyms Bromoethane Bromic ether Halon 2001 Hydrobromic ether Monobromoethane Chemiical/Pharmaceutical/Other Class Halogen-ated aliphatic hydrocarbons Chemcial Formula CiHsBr Chemical Structure ... 

SYNONYMS bromic ether, bromoethane, halon 2001, hydrobromic ether, monobro-moethane... 

Synonyms bromoethane monobromoethane hydrobromic ether Halon 2001... 

Synonyms Bromic ether Bromoethane Ethane, bromo- Hydrobromic ether ... 

Hydrobromic acid sol n.. See Hydrobromic acid Hydrobromic ether. See Ethyl bromide HydroCai ii 36, HydroCai ii 38, HydroCai ii 45, HydroCai ii 60, HydroCai ii 100, HydroCai ii 200, HydroCai ii 500, HydroCai ii 625, HydroCai ii 750, HydroCai ii 850, HydroCai ii 1200, HydroCai ii 1400, HydroCai ii 2000, HydroCai ii 2400, HydroCai ii 3000, HydroCai ii 4500. See Naphthenic oil... 

Bromoacetic acid can be prepared by the bromination of acetic acid in the presence of acetic anhydride and a trace of pyridine (55), by the HeU-VoUiard-Zelinsky bromination cataly2ed by phosphoms, and by direct bromination of acetic acid at high temperatures or with hydrogen chloride as catalyst. Other methods of preparation include treatment of chloroacetic acid with hydrobromic acid at elevated temperatures (56), oxidation of ethylene bromide with Aiming nitric acid, hydrolysis of dibromovinyl ether, and air oxidation of bromoacetylene in ethanol. 

Bismuth tribromide may be prepared by dissolving Bi O in excess concentrated hydrobromic acid. The slurry formed is allowed to dry in air, then gendy heated in a stream of nitrogen to remove water, and finally distilled in a stream of dry nitrogen. Bismuth tribromide is soluble in aqueous solutions of KCl, HCl, KBr, and KI but is decomposed by water to form bismuth oxybromide [7787-57-7] BiOBr. It is soluble in acetone and ether, and practically insoluble in alcohol. It forms complexes with NH and dissolves in hydrobromic acid from which dihydrogen bismuth pentabromide tetrahydrate [66214-38-8] H2BiBr 4H2O, maybe crystallized at —lO C. 

Hydrogen bromide adds to acetylene to form vinyl bromide or ethyHdene bromide, depending on stoichiometry. The acid cleaves acycHc and cycHc ethers. It adds to the cyclopropane group by ring-opening. Additions to quinones afford bromohydroquinones. Hydrobromic acid and aldehydes can be used to introduce bromoalkyl groups into various molecules. For example, reaction with formaldehyde and an alcohol produces a bromomethyl ether. Bromomethylation of aromatic nuclei can be carried out with formaldehyde and hydrobromic acid (6). 

Methyl bromide slowly hydrolyzes in water, forming methanol and hydrobromic acid. The bromine atom of methyl bromide is an excellent leaving group in nucleophilic substitution reactions and is displaced by a variety of nucleophiles. Thus methyl bromide is useful in a variety of methylation reactions, such as the syntheses of ethers, sulfides, esters, and amines. Tertiary amines are methylated by methyl bromide to form quaternary ammonium bromides, some of which are active as microbicides. 

Ethers are weakly basic and are converted to unstable oxonium salts by strong acids such as sulfudc acid, perchlodc acid, and hydrobromic acid relatively stable complexes ate formed between ethers and Lewis acids such as boron trifluodde, aluminum chlodde, and Gtignatd reagents (qv) (9) ... 

B. a-Hydroxyphenazine (demethylalion). A solution of 4.2 g. (0.02 mole) of a-methoxyphenazine, from A above, in 125 ml. of 55% hydrobromic acid (Note 7) is placed in a 250-ml. round-bottomed flask fitted with a reflux condenser. The flask is immersed in an oil bath, and the solution is heated to 110-120° for 5 hours the evolved gases are absorbed with water in a trap. The reaction mixture is cooled to room temperature, diluted with about 125 ml. of water, almost neutralized with sodium hydro.xide (Note 8), and extracted six times with 30- to 40-ml. portions of ether. The combined ether extracts arc extracted with 25-ml. portions of 10% sodium hydroxide solution (Note 9) until no more purple sodium salt is remox ed from the ether. The aqueous extracts are combined, made acid to litmus with dilute acetic acid, and re-extracted four times with 50-ml. portions of ether. The combined ether extracts are dried over anhydrous sodium sulfate, and the ether is removed by distillation on a steam bath. The residue is recrystallized as follows It is dissolved in the least possible amount of hot alcohol, water... 

There still remains to be settled the point of attachment of the a-aminopropionic acid side-chain in leucenol. As the latter is unaffected by boiling hydrobromic or hydriodic acid, an ether linkage at C in 3-hydroxypyridone-4 is unlikely and as the side-chain is eliminated by either pyrolysis or the action of alkali C for the location, as suggested by Kostermanns see mimosine below) is improbable. The balance of evidence seems to be in favour of attachment to the N-atom and additional data supporting this view have been provided by Adams and Jones. ... 

Craig s synthesis of nicotine (V to VII, p. 42) proceeds via nomicotine. Nicotinic acid nitrile reacts with the Grignard reagent derived from ethyl y-bromopropyl ether to give 3-pyridyl-y-ethoxypropyl ketone (V). This yields an oily oxime (VI) reducible to a-(3-pyridyl)-a-amino-8-ethoxy-w-butane (VII), which with 48 per cent, hydrobromic acid at 130-3° gives womicotine, and this on methylation yields dZ-nicotine. 

The latter, by a similar series of reactions, yields homoajsecincheninic acid ethyl ether the silver salt of this on heating loses carbon dioxide, giving a quinolylphenetole, which, on dealkylation with hydrobromic acid, yields a quinolylphenol, identical with 4-o-hydroxyphenylquinoline. 

The hydrogenation of 5a-cholestanone (58) in methanolic hydrobromic acid over platinum gives 3j5-methoxycholestane ° (61). This compound is also obtained from the palladium oxide reduction of (58) in methanol in the absence of acid. Hydrogenation of 5 -cholestanone also gives the 3j5-methoxy product under these conditions. Reduced palladium oxides are quite effective for the conversion of ketones to ethers. The use of aqueous ethanol as the solvent reduces the yield of ether. Ketals are formed on attempted homogeneous hydrogenation of a 3-keto group in methanol. ... 

To 10 g of cyclohexane-1,4-oxide is added 48% aqueous hydrobromic acid (60 g). The phases are mixed thoroughly and allowed to stand at room temperature until the solution separates into two layers (usually 5 days). The mixture is saturated with sodium chloride and extracted twice with 25-ml portions of ether. The ether layer is washed with an equal volume of saturated sodium bicarbonate solution, then with the same amount of water. Finally, the ether solution is dried over anhydrous sodium sulfate, the ether is evaporated, and the residue is allowed to cool, whereupon crystallization should follow. The crude product may be recrystallized from petroleum ether giving material of mp 81-82° (yield, 11 g). 

That product was then heated under reflux with 50% hydrobromic acid for 1.5 hours. The reaction mixture was evaporated to dryness and reevaporated with three portions of propan-2-ol. The oil obtained was dissolved in propan-2-oi and diluted with ether. 3-Ethyl-3-(m-hydroxyphenyl)hexahydro-1 H-azepine was obtained. That material in turn was reductively methylated by hydrogenation in the presence of formaldehyde in absolute ethanol solution to give 3-ethyl-3-(m-methoxyphenyl)-1 -methylhexahydro-1 H-azepine. 

A solution of 3.1 g of (2-benzoyl-4-chlorophenyl-carbamoylmethyl)carbamic acid benzyl ester in 30 cc of 20% hydrobromic acid in glacial acetic acid was stirred for 45 minutes at room temperature. On addition of 175 cc of anhydrous ether, a gummy solid precipitated. After several minutes the ether solution was decanted. The resultant 5-chloro-2-gly-cylaminobenzophenone was not isolated, but about 155 cc of ether was added to the residue and after chilling in an ice bath, 10% sodium hydroxide was added until the mixture was alkaline. The ether layer was then separated, washed twice with water and dried over sodium sulfate. After filtration, the ether solution was concentrated to dryness in vacuo. The residue was crystallized from benzene to yield 7-chloro-5-phenyl-3H-1,4-benzodiazepin-2(1 H)-one. 

The bromo derivative 16 reacts with phenylmagnesium bromide in diethyl ether, followed by workup with 5% aqueous hydrobromic acid, to give 2-methyl-4,5-diphenyl-2//-2,3-benzo-diazepin-l(5//)-one (17) in 55% yield.137 No further details were reported. 

The reaction scheme is as follows (Fig. 21). It is reasonable to assume that BTMA Br3 can be dissociated by water as shown in Equation 1. The resulting hypobromous acid may act as the major active oxidizing species and may convert alcohols into esters as Equation 2. In the case of ethers, we can show as Equation 4. Generated hydrobromic acid can be removed by Na2HP04 which has been added previously (Eqn. 5). 

The mixed aliphatic - aromatic ethers are somewhat more reactive in addition to cleavage by strong hydriodic acid and also by constant b.p. hydrobromic acid in acetic acid solution into phenols and alkyl halides, they may be bromi-nated, nitrated and converted into sulphonamides (Section IV,106,2). 

Mediated by Tin. In 1983, Nokami et al. observed an acceleration of the reaction rate during the allylation of carbonyl compounds with diallyltin dibromide in ether through the addition of water to the reaction mixture.74 In one case, by the use of a 1 1 mixture of ether/water as solvent, benzaldehyde was allylated in 75% yield in 1.5 h, while the same reaction gave only less than 50% yield in a variety of other organic solvents such as ether, benzene, or ethyl acetate, even after a reaction time of 10 h. The reaction was equally successful with a combination of allyl bromide, tin metal, and a catalytic amount of hydrobromic acid. In the latter case, the addition of metallic aluminum powder or foil to the reaction mixture dramatically improved the yield of the product. The use of allyl chloride for such a reaction,... 

Oxidation of that compound with chromium trioxide in sulfuric acid leads cleanly to the desired ketone (67). Treatment with hydrobromic acid serves to demethylate the phenolic ether function (68). Direct... 

---