Trimethylene dibromide

Trimethylene Dibromide. In a 1-litre round-bottomed flask place 500 g. (338 ml.) of 48 per cent, hydrobromic acid and add 150 g. (82 ml.) of concentrated sulphuric acid in portions, with shaking. Then add 91 g. of trimethylene glycol (b.p. 210-215°), followed by 240 g. (130-5 ml.) of concentrated sulphuric acid slowly and with shaking. Attach a reflux condenser to the flask and reflux the mixture for 3 hours. Arrange for downward distillation and distil, using a wire gauze, until no more oily drops pass over (30—40 minutes). Purify the trimethylene dibromide... 

The derivatives of ethylene dibromide, propylene dibromide, trimethylene dibromide and tao-butylene dibromide melt at 260°, 232°, 229° and 223° respectively. 

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) ... 

Trimethylene dibromide (1 mol) condenses with ethyl malonate (1 mol) in the presence of sodium ethoxide (2 mols) to form ethyl cydobutane-1 1-dksrboxylate (I). Upon hydrolysis of the latter with alcoholic potassium hydroxide, followed by acidification cyciobutane-1 1-dicarboxylic acid (II) is obtained. 

Equip a 3 litre three-necked flask with a thermometer, a mercury-sealed mechanical stirrer and a double-surface reflux condenser. It is important that all the apparatus be thoroughly dry. Place 212 g. of trimethylene dibromide (Section 111,35) and 160 g. of ethyl malonate (Section 111,153) (dried over anhydrous calcium sulphate) in the flask. By means of a separatory funnel, supported in a retort ring and fitted into the top of the condenser with a grooved cork, add with stirring a solution of 46 g. of sodium in 800 ml. of super dry ethyl alcohol (Section 11,47,5) (I) at such a rate that the temperature of the reaction mixture is maintained at 60-65° (50-60 minutes). When the addition is complete, allow the mixture to stand until the temperature falls to 50-55°, and then heat on a water bath until a few drops of the liquid when added to water are no longer alkaline to phenolphthalein (about 2 hours). Add sufficient water to dissolve the precipitate of sodium bromide, and remove the alcohol by distillation from a water bath. Arrange the flask for steam distillation (Fig. this merely involves... 

Diethyl 1,1-cyclobutanedicarboxylate has been prepared by the alkylation of diethyl sodiomalonate with trimethylene dibromide 8i4>6 7 or with trimethylene chlorobromide 6-8 and by the peroxide-catalyzed addition of hydrogen bromide to diethyl allylmalonate followed by intramolecular alkylation.9 The procedure described here is that of Mariella and Raube.6... 

Trimethylene dibromide, dl21 Trimethylene dimercaptan, pi95 Trimethylene glycol, pi92 Trimethylethylene, ml66 Trimethylgermanium bromide, b437... 

Although it has been long known that trimethylene dithiotosylate can be prepared by the reaction of thiotosylate ion with trimethylene dibromide,3 5 various difficulties are associated with the preparation. These problems are to a considerable extent related to the mode of preparation and the resultant purity of potassium thiotosylate. The thiotosylate salt must be free of tosylate and p-toluenesulfiriate impurities, otherwise side products such as tosylates or sulfones will form. One such by-product, tosyltrimethylene thiotosylate,... 

Trimethylene dibromide available from Eastman Organic Chemicals, was distilled prior to use (b.p. 167-168°). 

Trimethylene dibromide, 54, 34 2,2- (TRIMETHYLENEDITHIO) CYCLOHEXANONE, 54, 39 Trimethylene dithiotosylate,... 

Kosolapoflf7 carried out a modified Arbusov reaction between triethyl phosphite and trimethylene dibromide and obtained tetraethyl trimethylenediphosphonate (VII, n = 3) and diethyl 3-bromopropylphosphonate (VI, n = 3). 

Trimethylacetic acid, 350, 351 Trimethylamine hydrochloride, 414,416 Trimethylene dibromide, 279 Trimethylene dicyanide, 407, 409 Trimethylene-di-iodide, 288 1 3 5-Trinitrobenzene, 965 addition compounds of, 519 ... 

Although the cyclic selenohydrocarbons having five- or six-membered rings are isolated in good yield by the interaction of alkylene dibromides and sodium selenide, trimethylene dibromide and sodium selenide furnish only a small yield of c cZoselenopropane,... 

Trimethylene chlorobromide, b257 Trimethylene chlorohydrin, c214 Trimethylenediamine, pi 93 Trimethylene dibromide, d93... 

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