1- 4-Dibromobutane

Dibromobutane and 1 5 dibromopentane are conveniently prepared from the readily available tetrahydrofuran (I) and tetrahydrop3uan (II) respectively ... 

Dibromobutane from 1 4 butanediol). In a 500 ml. threenecked flask fltted with a stirrer, reflux condenser and dropping funnel, place 154 g. (105 ml.) of 48 per cent, hydrobromic acid. Cool the flask in an ice bath. Add slowly, with stirring, 130 g. (71 ml.) of concentrated sulphuric acid. To the resulting ice-cold solution add 30 g. of redistilled 1 4-butanediol dropwise. Leave the reaction mixture to stand for 24 hours heat for 3 hours on a steam bath. The reaction mixture separates into two layers. Separate the lower layer, wash it successively with water, 10 per cent, sodium carbonate solution and water, and then dry with anhydrous magnesium sulphate. Distil and collect the 1 4-dibromo-butane at 83-84°/12 mm. The yield is 55 g. 

Dibromobutane (from 1 4-butanediol). Use 45 g. of redistilled 1 4-butanediol, 6-84 g. of purified red phosphorus and 80 g. (26 ml.) of bromine. Heat the glycol - phosphorus mixture to 100-150° and add the bromine slowly use the apparatus of Fig. Ill, 37, 1. Continue heating at 100-150° for 1 hour after all the bromine has been introduced. Allow to cool, dilute with water, add 100 ml. of ether, and remove the excess of red phosphorus by filtration. Separate the ethereal solution of the dibromide, wash it successively with 10 per cent, sodium thiosulphate solution and water, then dry over anhydrous potassium carbonate. Remove the ether on a water bath and distil the residue under diminished pressure. Collect the 1 4-dibromobutane at 83-84°/12 mm. the yield 3 73 g. 

Thionyl chloride readily converts butanediol to 1,4-dichlorobutane [110-56-5] (130) and hydrogen bromide gives 1,4-dibromobutane [110-52-1]... 

Amino-3-phenylisothiazole cyclizes on reaction with 2-azido-3-ethylbenzothiazolylium borofluoride to give compound (110) (78HCA108). 4-Aminoisothiazole reacts with 1,4-dibromobutane to give 4-pyrrolidinylisothiazole (80MI41700). 

With Freon 112 or 113 as a solvent, fluonnation of pnmary butyl halides with bromine trifluonde can give mixtures of primary and secondary fluorides When 1,4 dibromobutane is the substrate, 93% l-bromo-4-fluorobutane and 1% 1-bro-mo-3-fluorobutane is obtained, with 1,4 dichlorobutane, the product contains 65% l-chloro-3-fluorobutane and 35% 1-chloro 4 fluorobutane When 4-bromo- or 4-chlorobutyl trifluoroacetate is used, the ratio of 4-fluorobutyl tnfluoroacetate to 3 fluorobutyl trifluoroacetate is 1 4 The effect of solvent is measured in another set of experiments When the reaction of bromine trifluonde and l,3-dichloro-2-fluoropropane in either Freon 113 or hydrogen fluoride is allowed to proceed to 40% conversion, the product mixture has the composition shown m Table 1 [/O] When 1 chloro 2,3-dibromopropane is combined with one-third of a mole of bromine trifluonde, both 1 bromo 3 chloro-2-fluoropropane and l-chloro-2,3-di-fluoropropane are formed [//] (equation 10)... 

In fact, esters of amino alcohols and 2,2-disubstituted plii iiylacetic acids show useful antitussive activity the mecha-lM iii of action may include bronchiodilation. Double alkylation III the anion of phenylacetonitrile with 1,4-dibromobutane gives llit i cyclopentane-substituted derivative (33). Saponification... 

A quantitative study of the nucleophilic displacement reaction of benzoyl chloride with cyanide ion in [BMIM][PFg] was investigated by Eckert and co-workers [52]. The separation of the product, 1-phenylacetonitrile, from the ionic liquid was achieved by distillation or by extraction with supercritical CO2. The 1-phenylacetonitrile was then treated with KOH in [BMIM][PF6] to generate an anion, which reacted with 1,4-dibromobutane to give 1-cyano-l-phenylcyclopentane (Scheme 5.1-23). This was in turn extracted from the ionic liquid with supercritical CO2. These... 

Scheme 5.1-23. The reaction of cyanide with benzyl chloride to produce 1-phenylacetonitrile, and subsequent treatment with 1,4-dibromobutane.

The synthesis of phosphonium iodide 24, the precursor of phos-Br phorus ylide 12, begins with the alkylation of 5-lithio-2-methyl- furan,10 derived from the action of n-butyllithium on 2-methylfuran 17 (16), with 1,4-dibromobutane (17) to give 15 in 75% yield (see... 

Finally, we mention the use of the polyquat bromide "Dab-4-Br" - easily prepared from Dabco and 1,4-dibromobutane - in the synthesis (ref. 7) of gmelinite (a 1-D 12-ring zeolite). 

In a similar fashion, Li and co-workers have described the synthesis of bis-amides 145 by the reaction of 1,4-dibromobutane with the piperazine counterparts 144 (Equation 33) <2003BML1729>. The compounds were tested as analgesics yields were not reported. 

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