Partial hydrolysis of a benzonitrile; 4-(trans-4-Pentylcyclohexyl)benzamide
SyntheticPage 710
DOI:
10.1039/SP710
Submitted Dec 19, 2013, published Jan 06, 2014
Chemicals Used
4-(Trans-4-pentylcyclohexyl)-benzonitrile (Fluorochem), 300840
Potassium hydroxide, pellets, Sigma Aldrich, 85+%, 22,147-3
Ethyl alcohol, 190 proof, Sigma Aldrich , 95+%, 49,351-1
Silicon carbide (boiling stones), Sigma Aldrich, 400 mesh, 35,739-1
Procedure
A 200 ml round bottom one neck flask equipped with a heating mantle and magnetic stirrer was charged with ethanol (60 ml, 95%). Stirring was commenced and potassium hydroxide pellets (4 g) were added slowly over ~ 15 min and the mixture further stirred until all pellets had dissolved. 4-(trans-4-pentylcyclohexyl)-benzonitrile (3.09g, 12 mmol) was added and the mixture was stirred until homogeneous. The solution was then diluted with distilled or deionized water (20 ml), two silicon carbide boiling stones added, and a water condenser attached. Heating was commenced and the solution taken to full reflux for ~12 h (overnight). During this period a copious white precipitate of amide separated from the solution. The solution was allowed to cool to room temperature and the precipitate collected on a Buchner funnel by suction filtration. The walls of the flask were washed water (2 x 10 ml) which were in turn filtered with the Buchner funnel. Boiling stones and stirring bar were mechanically removed with a spatula. The white solid was transferred to a large watch glass and air dried overnight yielding the amide (2.9 g, 88%). The material required no further purification.
Author's Comments
Potassium hydroxide pellets are very irritating and hygroscopic. Wear latex gloves and weigh quickly or in a dry box. By entirely analogous procedures other benzonitriles were hydrolyzed to amides in high yield with no detectable carboxylic acids from full hydrolysis. See primary and secondary references.
Data
m.p. 234-5⁰C. IR (dichloromethane) 3300,3010,2970,2950,1640 cm-1. Analysis: Calculated for C18H27NO: C 79.06, H 9.96, N 5.12; Found: C 79.36, H 10.04, N 5.07.
Lead Reference
John H. MacMillan and Mortimer M. Labes, "Low Transition Temperature Liquid Crystalline Amines Incorporating the Trans-1,4-Cyclohexane Ring System", Molecular Crystals and Liquid Crystals, Vol. 55, p 61, (1979). DOI: dx.doi.org/10.1080/00268947908069791
Other References
John H. MacMillan and Mortimer M. Labes, "Low Transition Temperature Liquid Crystalline Amines Incorporating the Biphenyl Ring System", Mol. Crystals and Liquid Crystals Letters, Vol. 56, p51, (1979). DOI: Link: http://dx.doi.org/10.1080/01406567908071966
John H. MacMillan and Mortimer M. Labes, "Amine Substituted Liquid Crystal Compositions", U.S. Patent 4,293,193, Oct. 6, 1981.
Chemspider deposition: http://www.chemspider.com/Chemical-Structure.29354290.html
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Keywords: addition, amides, benzamides, benzonitriles, carboxylic acids, cyanides, hydrolysis, hydroxylation, nitriles