Methylene dibromide

Trimethylene dibromide (Section 111,35) is easily prepared from commercial trimethj lene glycol, whilst hexamethylene dibromide (1 O dibromohexane) is obtained by the red P - Br reaction upon the glycol 1 6-hexanediol is prepared by the reduction of diethyl adipate (sodium and alcohol lithium aluminium hydride or copper-chromium oxide and hydrogen under pressure). Penta-methylene dibromide (1 5-dibromopentane) is readily produced by the red P-Brj method from the commercially available 1 5 pentanediol or tetra-hydropyran (Section 111,37). Pentamethylene dibromide is also formed by the action of phosphorus pentabromide upon benzoyl piperidine (I) (from benzoyl chloride and piperidine) ... 

DecabromodiphenylOxide. Decabromodiphenyl oxide [1163-19-5] (decabrom) is the largest volume bromiaated flame retardant used solely as an additive. It is prepared by the bromination of diphenyl oxide ia neat bromine usiag AlCl as a catalyst (32). The bromination may also be carried out ia an iaert solvent such as methylene dibromide [74-95-3] (33). The commercially available grades are >98% decabromodiphenyl oxide with the remainder being the nonabromo species. 

Bashall and Collins4S have treated catechol (9) with methylene dibromide under PTC conditions in the presence of Adogen. The 76% yield in this reaction is comparable to that obtained in DMSO,46 but PTC is much more convenient. In DMSO, addition of pelleted sodium hydroxide and catechol is required in the absence of air. 

Cyclopropanes 1,1,2-trisubstituted with electron-withdrawing groups are prepared by treating electron-deficient alkenes with dibromomalonic ester or related active methylene dibromides in the presence of trialkylstibine (equation 132))290 291, dibutyl telluride292 or... 

Cyclopropanation.1 Electron-deficient alkenes react with active methylene dibromides and indium to form cyclopropanes in 35-95% yield. Reaction of aldehydes with dibromomalononitrile, lithium iodide, and indium also provides epoxides. 

In a free radical ring expansion reaction discovered quite recently [24] [25], a methyl or ethyl cycloalkanone-2-carboxylate was first alkylated with methylene-dibromide [24] or bromomethylphenylselenide [25], Scheme VII/11. 

SYNS METHYLENE BROMIDE METHYLENE DIBROMIDE RCRA WASTE NUMBER U068... 

METHYLENE DIBROMIDE see DDP800 METHYLENE DICHLORIDE see AIJP450... 

Preparation of the simplest diamine, ethylene diamine, by ammonolysis of the dihalide is accompanied by the formation of diethylenediamine and triethylenetetramine other methods for its preparation are more suitable. Only the higher homologs of /3-dialkylaminoethyl bromide respond favorably to this treatment. Thus, di-n-butylaminoethyl bromide is converted to the diamine in 55% yield whereas the dimethylaminoethyl bromide undergoes extensive dimerization. Triniethylene bromide reacts with liquid ammonia to form trimethylenediamine (50%) however, experimental details are lacking. When the two halogens in the dihalide approach one another in space as in tetra- and penta-methylene dibromides, then nitrogen spiranes are the main products. ... 

METHYLENE DIBROMIDE (74-95-3) CHjBrj Noncombustible liquid. Incompatible with some alkali metals amines, azo/diazo compoimds dialkylzincs, dimethyl sulfoxide, dimethyl formamide, epoxides such as glycidol, ethylene glycol diethyl ether, ethers, nitrides. Mixture with potassium produces a sensitive impact-sensitive explosive material and may react with other metals, forming dangerous materials. 

Beilstein Handbook Reference) AI3-52311 BRN 0969143 CCRIS 939 Dibromomethane EINECS 200-824-2 HSDB 1334 Methane, dibromo- Methylene bromide Methylene dibromide NSC 7293 RCRA waste number U068 UN26M. Used in the production of leaded gasoline, as a fumigant for stored products and as a nematocide. Also used in the manufacture of fire retardent chemicals. Dense, mobile liquid mp = -52.5 bp = 97 d = 2.4969 soluble in organic solvents, slightly soluble in H2O. 

Reduction by lithium aluminum deuteride provides another method for direct replacement of halogen by deuterium, especially aliphatically bonded halogen for example, methylene dibromide is converted into deuterated methane in 93% yield.58 A mixture of LiD and LiAlD4, usually in tetrahydro-furan, is recommended59,60 especially for difficultly reducible compounds. This reduction is an SN 2 reaction, with the result that configuration is inverted at optically active centers, e.g., (R)-(+)-[2-D]butane is obtained from ( )-(+)-2-bromobutane in 82% yield 61... 

The removal of halogen with intermolecular formation of a new carbon-carbon double bond may be regarded as an extension of the Wurtz-Fittig reaction it has been applied almost exclusively to the preparation of hydrocarbons but its importance is mainly in the stilbene series. Buckles and Matlack870 prepared tetraphenylethylene in 70% yield by treating diphenylmethylene dibromide with copper powder and tetrakis-(p-nitrophenyl)ethylene has been obtained in 47% yield from bis-(p-nitrophenyl)methylene dibromide by means of pentacarbonyliron.8 71... 

The recently discovered reaction880 of methylene dibromide or diiodide with carbonyl compounds in the presence of magnesium amalgam provides an extremely simple synthesis of terminal olefins ... 

General procedure A solution of the carbonyl compound (0.25 mole) and methylene dibromide (or diiodide) (0.26 mole) in ether (100 ml) is added during 2 h to a stirred suspension of magnesium amalgam (from 0.5 mole of magnesium in 400 g of mercury) in ether (100 ml) under dry argon. The whole is boiled for 30 min under reflux and then worked up. 

The results obtained from the irradiation at 235 nm of vibrationally excited dichloromethane suggest that there is higher non-adiabaticity for vibrationally excited molecules.Laser irradiation at 355 nm of methylene chloride and methylene bromide brings about ionization.A simple C-Br bond fission is the key step in the photodissociation of methylene dibromide at 248 nm. Ionization of methylene bromide in the 10-24 eV range has been reported. Irradiation of methylene iodide in water has provided evidence for the formation of iodine atoms and protons.Further work on the photochemical behaviour of methylene iodide has reported that vibrationally relaxed CH2l- T reacts with cyclohexene to afford norcarane. ... 

The biphenylylphosphine (75) undergoes similar cyclic quaternization with methylene dibromide to give the dissymmetric salt (76), which can be monodeprotonated to give dissymmetric (77) further deprotonation of (77) gave 9,9-dimethyl-92 -phosphaphenanthrene (78) <82CB1367>. 

Methylene dibenzene. See Diphenylmethane Methylene dibromide. See Methylene bromide Methylene dichloride. See Methylene chloride 4,4 -Methylenedicyclohexaneamine Methylene di(cyclohexylamine) 4,4 -Methylenedicyclohexylamine. See Bis (p-aminocyclohexyl) methane Methylenedi-4-cyclohexylene diisocyanate. See... 

Phase transfer catalysis has been used in the methylenation of carbohydrates methyl 4,6-0-benzylidene-glucosides and galactosides gave the /raw -fused 2,3-acetals in about 60% yield with methylene dibromide and alkali. Methyl jS-D-ribofuranoside gave the fully substituted dimeric compound (1), and its 5-trityl derivative afforded the monomeric 2,3-acetal as anticipated, ... 

As an alternative to Corey s reagent, methylene dibromide in the presence of Li may be used to convert aldehydes and ketones to epoxides in 35-90% yield. ... 

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