Tetramethylene dibromide

Condensation of 7-methoxy-3,4-dihydro-1(2H)-naphthal-enone with tetramethylene dibromide by means of NaH in benzene or tert amyl alcohol gives 3,4-dihydro-7-methoxy-2,2-tetramethylene-1(2H)-naphthalene (bp (0,05 mbar) 120-123 °C), which is treated with acetonitrile and butyllithium in THF yielding 1-hydroxy-7-methoxy-1,2,3,4-tetrahydro-2,2-tetramethylene-1-naphthalene-acetonitrile (mp 140-142 °C). This compound is reduced with LiAIH4 in THF to afford hydro-2,2-tetramethylene-1-naphthol (mp 178-180 °C), and isomerized to 4a-(2-aminoethyl)-1,2,3,4,4a,9-hexahydro-6-methoxy-phenantrene i (mp 187 °C). 

A mixture of c cZoselenobutane, a8-tetramethylene dibromide and water is heated at 90° C. in a sealed tube with occasional shaking until no more material dissolves in the aqueous layer. The solution is then evaporated over sulphuric acid until the complex dibromide separates as colourless prisms. These prisms after drying in vacuo melt at 95° to 96° C. 

The preparation and purification of this compound is identical with that of cycZoselenobutane, the aS-tetramethylene dibromide in the latter case now being replaced by 27 grams of ae-pentamethylene dibromide. The product need only be distilled under ordinary pressure in a stream of carbon dioxide to effect purification. It is a colourless or very faintly yellow liquid, B.pt. 158° C. at 759 mm., nv 1 5475 at 18° C., density 1 409 at 12 5° C., 1 899 at 20° C., 1 892 at 26° C., and 1 884 at 32 2° C., whence d ° - 1 424 0-001236f. The compound has similar properties to those described for o/cZoselenobutane. The mercurichloride, C6H10Se. HgCl2, forms white, feathery needles, M.pt. 175° to 176° C. cycloSelenipentane I 1 -dichloride,... 

Pyrrolidine (39 Z = NH) and thiolane (39 Z = S) can be prepared from tetramethylene dibromide 38, and tetrahy-drofuran (39 Z = O) is obtained from the diol 40. -Hydroxy and -thiol acids (41 Z = O, S) usually cyclize spontaneously to give lactones and thiolactones 42. -Amino acids (41 Z = NH) require heating to effect lactam formation (42 Z = NH) (Scheme 31). 

Beilstein Handbook Reference) AI3-14617 BRN 1071199 Butane, 1,4-dibtomo- OBB 1.4-Dibrombutan 1,4-Dibromobutane a.co-Dibromobutane EINECS 203-775-5 NSC 71435 Tetramethylene dibromide Tetramethylenebromide. Used in chemical synthesis. Liquid mp = -20° bp = 197° d = 1.8080 insoluble in H20, slightly soluble in CCl4, soluble in CHCla.organic solvents. Humphrey Janssen Chimica. 

To a dry flask containing 15 ml of absolute ethanol is added 0.46 gm (0.02 gm atom) of sodium metal. After the metal dissolves 1.5 gm (0.01 mole) of hexamethylenedithiol is added. The disodium salt of the dithiol precipitates and is then redissolved when the mixture is heated. To the hot solution is added 25 ml of dry thiophene-ffee benzene followed immediately by 2.15 gm (0.01 mole) of tetramethylene dibromide. An immediate vigorous reaction is initiated and the solvent begins to reflux. When the reaction subsides, another 25 ml of benzene is added and the mixture refluxed overnight. The polymer is isolated by pouring the reaction mixture into methanol. The polymer yield is 1.08 gm (50%) (m.p., 63°-65°C inherent viscosity, 0.36 dl/gm). 

Attempted alkylations of 3-benzyloxy-6- and 2-benzyloxy-5-methylpyridine with tetramethylene dibromide have been unsuccessful. ... 

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