Acetate → HCID 130298492, compound

Participants

Reaction Steps

(±)-cis-4-Acetamidocyclopent-2-enemethyl acetate [U.S. Pat. No. 4,268,672] (14.88 g, 0.073 mol) and barium hydroxide octahydrate (46.19 g), 0.146 mol) were refluxed in water (300 ml) under nitrogen for 18 hours. The resulting solution was neutralised with carbon dioxide. The precipitate was washed with water, then ethanol. The combined filtrate was evaporated to a syrup, (acetic acid salt of (±)-4-amino-2-cyclopentene-1-methanol) which converted to free amine by stirring with an excess of Amberlite IRA-400 (OH-) resin in water. The resin was filtered off, washed with water, and the filtrate-wash evaporated to a pale yellow syrup which was dried by evaporation of portion of ethanol. Such a sample of amine (2.26 g, 20.0 mmol) and dibenzoyl-D-tartaric acid (Aldrich, 3.62 g, 10.0 mmol as 99%) were dissolved in hot absolute ethanol (35 ml). Refluxing acetonitrile (ca. 150 ml) was added to the cloud point and the solution was allowed to cool slowly to room temperature. The white needles which formed were recrystallized three times from the same solvent combination to give title compound as white plates (1.07 g, 37%); m.p. 160°-162°; [α]D20 +66.9°, [α]43620 +165°, [α]36520 +325° (c=0.28, methanol). X-ray crystallography of this salt allowed the absolute configuration of the cation to be fixed by the known configuration of the D-dibenzoyl tartaric acid dianion. This salt crystallized in the space group C2 with one C6H12NO cation and one-half C18H14O8 dianion as the asymmetric unit.

Provenance & Evidence