In a 250 mL bottomed flask, ammonia was bubbled into ethanol (80 mL) that was cooled to -78° C. for 45 min. The saturated solution that was obtained was transferred to a Parr autoclave, which contained 4-chlorobutanenitrile (60 g, 580 mmol). The mixture was stirred and heated to 120° C for 16 hr. The reaction mixture was cooled and transferred to a round-bottomed flask. The solvent was removed under reduced pressure to afford a yellow solid, which was washed with diethyl ether and dried under a high vacuum to afford an off-white solid 2-Amino-1-pyrroline Hydrochloride, 19.5 g, 232 mmol, 40percent yield. 1H NMR (DMSO-d6) δ 9.22 (br s, 1H), 8.93 (br s, 1H), 7.60 (br s, 1H), 3.52 (d, J=7.2 Hz, 2H), 2.76 (d. J=8.0 Hz, 2H), 2.08-1.96 (m, 2H).