Org. Synth. 1953, 33, 68
DOI: 10.15227/orgsyn.033.0068
Submitted by E. R. H. Jones, Geoffrey Eglinton, and M. C. Whiting1.
Checked by Arthur C. Cope and Ronald M. Pike.
1. Procedure
Caution! This preparation should be conducted in a hood to avoid exposure to ammonia.
A solution of sodium amide in liquid ammonia is prepared according to a procedure previously described (Note 1) in a 3-l. three-necked round-bottomed flask equipped with a cold-finger condenser (cooled with Dry Ice) attached through a soda-lime tower to a gas-absorption trap,2 a mercury-sealed stirrer, and an inlet tube. Anhydrous liquid ammonia (1 l.) is introduced from a commercial cylinder through the inlet tube, and 1 g. of hydrated ferric nitrate is added, followed by 80.5 g. (3.5 g. atoms) of clean, freshly cut sodium (Note 1) and (Note 2). The inlet tube is replaced with a 250-ml. dropping funnel, and the mixture is stirred until all the sodium is converted into sodium amide, after which 120.5 g. (1 mole) of tetrahydrofurfuryl chloride3 (Note 3) is added over a period of 25 to 30 minutes. The mixture is stirred for an additional period of 1 hour, after which 177 g. (3.3 moles) of solid ammonium chloride is added in portions at a rate that permits control of the exothermic reaction. The flask is allowed to stand overnight in the hood while the ammonia evaporates. The residue is extracted thoroughly with ten 250-ml. portions of ether, which are decanted through a Büchner funnel (Note 4). The ether is distilled, and the residue is fractionated at a reflux ratio of about 5 to 1, through a column containing a 20-cm. section packed with glass helices yielding 63–71 g. (75–85%) of 4-pentyn-1-ol, b.p. 70–71° /29 mm., nD25 1.4443 (Note 5).
2. Notes
1. Procedures for converting sodium to sodium amide are given on p. 763 and in a previous volume.4
2. More liquid ammonia should be added through the inlet tube if vaporization reduces the liquid volume to less than 750 ml.
3. Freshly distilled tetrahydrofurfuryl alcohol should be used in the preparation of tetrahydrofurfuryl chloride according to the procedure of Organic Syntheses.3
4. Ether extraction of the solid must be thorough or the yield will be reduced. A large Soxhlet extractor may be used if desired.
5. Others have reported b.p. 154–155°, nD19 1.4432;5 b.p. 154–155°, nD22.5 1.4450.6 A sample purified through the silver derivative had b.p. 77° /37 mm., nD15 1.4464. The α-naphthylurethan of 4-pentyn-1-ol crystallized as needles from 60–80° petroleum ether; m.p. 79–80°.
3. Discussion
4-Pentyn-1-ol has been prepared from 4-penten-1-ol3 by bromination followed by dehydrobromination with alkali;6 by the reaction of 3-bromodihydropyran or 3,4-dihydro-2H-pyran with n-butylsodium, n-butyllithium, or n-butylpotassium;5,7 by the reaction of dihydropyran or 2-methylenetetrahydrofuran with n-amylsodium or n-butyllithium;7 by the reduction of ethyl 4-pentynoate with lithium aluminum hydride;8 and by the method used in this preparation.9

References and Notes
  1. Victoria University of Manchester, Manchester, England.
  2. Org. Syntheses Coll. Vol. 2, 4 (1943).
  3. Org. Syntheses Coll. Vol. 3, 698 (1955).
  4. Org. Syntheses Coll. Vol. 3, 219 (1955).
  5. Paul and Tchelitcheff, Compt. rend., 230, 1473 (1950); Paul, Angew. Chem., 63, 304 (1951); Paul, Bull. soc. chim. France, 18, 109 (1951).
  6. Lespieau, Compt. rend., 194, 287 (1932).
  7. Paul and Tchelitcheff, Bull. soc. chim. France, 19, 808 (1952).
  8. Colonge and Gelin, Bull. soc. chim. France, 1954, 799.
  9. Eglinton, Jones, and Whiting, J. Chem. Soc., 1952, 2873.

Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

petroleum ether

α-naphthylurethan of 4-pentyn-1-ol

ammonia (7664-41-7)

ether (60-29-7)

ammonium chloride (12125-02-9)

sodium (13966-32-0)

tetrahydrofurfuryl alcohol (97-99-4)

sodium amide (7782-92-5)

n-butyllithium (109-72-8)

ferric nitrate

lithium aluminum hydride (16853-85-3)




4-Penten-1-ol (821-09-0)

Tetrahydrofurfuryl chloride (3003-84-7)

4-Pentyn-1-ol (5390-04-5)


3,4-dihydro-2H-pyran (110-87-2)

ethyl 4-pentynoate (63093-41-4)