Hydrochloric Acid → HCID 54234781, compound

Participants

Reaction Conditions

Reaction Steps

Under an atmosphere of nitrogen, propenylmagnesium bromide is prepared from 9.72 g of magnesium turnings (400 mmoles), freshly distilled 1-bromo 1-propene (cis/trans mixture, 24.2 g, 200 mmoles) and 180 ml of dry tetrahydrofuran. The colored solution is separated from the excess of magnesium and cooled to -30° C. Fluoroacetonitrile (11.8 g, 200 mmoles) in tetrahydrofuran (50 ml) is added dropwise during 20 mins and the reaction mixture is kept at -30° C. for an additional 20 mins. A solution/suspension of sodium borohydride (7.6 g, 200 mmoles) in methanol (400 ml) and water (8 ml) cooled to -50° C. is poured into the reaction mixture previously cooled to -50° C. The temperature rises to -10° C., and after cooling to -30° C. the temperature is allowed to rise to 0° C. during 1.5 hours. The mixture is acidified with 6 N hydrochloric acid, evaporated, the residue is diluted with water, extracted twice with diethyl ether to remove by-products, made alkaline with 4 N sodium hydroxide and extracted again twice with diethyl ether. After drying over sodium sulfate and filtration, dry hydrogen chloride gas is bubbled through the etheral solution. The oily precipitate formed (12 g, 43%) is dissolved in water, filtered, saturated with sodium chloride, made alkaline with 4 N sodium hydroxide and extracted twice with small portions of diethyl ether. After removing the ether at normal pressure, the black oily residue is distilled under reduced pressure (15 mm Hg) to give a colorless liquid (4.4 g, 21%, bp15 60°-100° C.) which is distilled again at normal pressure (some decomposition) to afford 1-fluoro-2-amino-3-pentene (cis/trans mixture, 2.8 g, 13%, bp 110°-180° C.) as a colorless oil. NMR (CDCl3) ppm 1.45 (2H, s, --NH2), 1.67 (3H, d of broad s, J=6 Hz), 3.83 (1H, broad m), 4.22 (2H, d of m, JH-F =46 Hz), 5.42 (2H, broad m).

Provenance & Evidence