Synthesis
The general procedure for the synthesis of 2-alkynyl-N-butylcarbamates from butyl bromide and 2-propyn-1-ol is as follows:
Example I Synthesis of benzyl propargyl carbamate: a mixture of n-butyl bromide (8.8 g, 0.064 mol), 2-propyn-1-ol (3 g, 0.054 mol), potassium cyanide (6.5 g, 0.08 mol), and tetrabutylammonium bromide (1.7 g, 0.005 mol) was heated to 70 °C in acetonitrile (45 mL), and the reaction was carried out under nitrogen protection for 22 hours. After completion of the reaction, the insoluble precipitate was removed by filtration and the filtrate was concentrated by rotary evaporator to give a yellow oil (6.7 g). Purification by column chromatography (silica gel, 15/85 ethyl acetate/hexane) gave N-alkynyl carbamate (4.4 g, 53% yield) as a colorless oil.
NMR (CDCl3, ppm): δ 4.75 (2H, s), 3.2 (2H, m), 2.5 (1H, s), 1.4 (4H, m), 1.0 (3H, t).
GC/MS (m/e): 155 (M+), 112 (100%), 74, 57, 56.
