Ammonia → 7,11-Hexadecadiyn-1-ol, 1-acetate

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Reaction Steps

Two hundred and thirty grams of 1,5-decadiyne (1.7 mols) in 1200 ml of tetrahydrofuran is added to a suspension of 39 g (1.6 mols) of lithium amide in approximately 5 liters of liquid ammonia. After 3 hours, 224 g (0.85 mol) of the tetrahydropyranyl ether of hexamethylene bromohydrin was added to the deep red solution, and the mixture was then stirred overnight. Most of the ammonia was allowed to evaporate and water is then cautiously added to the residue. The bottom aqueous layer is extracted once with ether and combined with the upper organic layer, which is then washed once with water, followed by saturated salt solution. Ether and THF are removed on a roto vap and the residue is refluxed for 4 hours with a mixture of 500 ml glacial acetic acid and 100 ml of acetyl chloride. Then about 400 ml of acetic acid and other low boiling products are distilled off and residue is poured into ice water. The lower aqueous layer is extracted with ether, combined with the upper layer, washed, etc., and distilled, yielding 145 g (0.52 mols) 7,11-hexadecadiynyl acetate by 130°-132°/torr, nD21 1.4706 (61% based on starting THP derivative of hexamethylene bromohydrin).

Provenance & Evidence