Preparation of 9-chloronon-4-yne
To stirred 300 ml of liquid ammonia through which acetylene is being bubbled, 5.5 g of small pieces of sodium are added at such a rate that the blue colour just disappears before the next piece of sodium is introduced. The acetylene flow is stopped at the exact moment when the blue coloration due to the last piece of sodium is discharged. 41 g of n-propyl iodide is then slowly introduced and the reaction mixture stirred for 4 hours. A suspension of sodium amide in 150 ml of liquid ammonia, prepared from 5.8 g of sodium by the usual ferric nitrate process, is then added in portions with strong cooling. The mixture is stirred for a further 1 hour and 41 g of d 1-chloro-4-bromobutane are then added dropwise. The reaction is completed by stirring the cooled mixture for a further 12 hours. After the addition of 15 g of ammonium chloride the ammonia is allowed to evaporate off and the residue worked up in the usual fashion by treatment with water and ether. Evaporation of the dried extract and distillation furnishes unchanged 5.3 g of 1-chloro-4-bromobutane and 9-chloronon-4-yne (24.2 g; 64%), b.p. 83-84°/15 mm, nD=1.4620.
Raphael, R. A., Sondheimer, F., ibid. (1950) 115
Acetylenic compounds in organic synthesis, by R. R. Alexander, 195-196, 1955