Hydrochloric Acid → N-cyanohexadecanamide

A solution of palmitoyl chloride (5.5 g, 0.020 mol) in 50 ml of freshly distilled dry THF was added drop-wise to a suspension of sodium cyanamide (3.84 g. 0.060 mol) in 150 ml of freshly distilled dry THF at ice bath temperature. After the addition, the ice bath was removed and the reaction was allowed to proceed at 25° C for 43 hours. The solids that formed were filtered to yield 8.48 g of waxy solid residue. The residue was ground to a fine powder and stirred in 150 ml of distilled water at ice bath temperature. The resulting soapy suspension (pH 11) was acidified to pH 2 with 10% HCl, then filtered and air-dried to give 5.4 g (96.3% yield) of crude 6 as a white solid. This was dissolved in warm THF and the mixture filtered. The filtrate was concentrated in vacuo until the solution became slightly turbid. This material was crystallized from THF/petroleum ether to yield 3.6 g (crop 1) of white powder. The filtrate was concentrated and crystallized in the same fashion to yield additional 0.6 g (crop 2) of white powder (74.8% total yield), mp 62°-65° C. TLC: Rf =0.68 in ethyl acetate/petroleum ether/glacial acetic acid (10:20:1); IR (Nujol, cm-1) 3230 (NH), 2250 (C≡N), 1740 (C=O); NMR (Silanor C, δ from TMS) 1.3-1.6 (t, --CH2 --CH2 --C=O), 1-1.8 (m, --(CH2)13 --), 0.8-1 (t, CH3 --CH2 --); Anal. Calcd for C17H32N2O: C, 72.81; H, 11.50; N, 9.99. Found: C, 72.69; H, 11.65; N, 9.68.