Sodium Hydroxide → (+/-)-cis-1-(10-Bromophenanthrene-2-carbonyl)piperazine-2,3-dicarboxylic acid

Participants

Reaction Conditions

Reaction Steps

10-Bromophenanthrene-2-carboxylic acid (2, 0.663 g, 2.2 mmol) was added to benzene (50 ml) containing excess thionyl chloride and the mixture heated under reflux overnight. The following day, the mixture was evaporated under reduced pressure and the resulting acid chloride (3) used without further purification. (_)-Cis-piperazine-2,3-dicarboxylic acid (4, 0.46 g, 2.6 mmol) was added to 0.991 M aqueous sodium hydroxide (8 ml, 8 mmol) and dioxan (10 ml) and the mixture was cooled to 0° C. A solution of the crude acid chloride (3) in dry dioxan was then added and the mixture was stirred at 0° C. for 5 min and then at room temperature overnight. The following day, the reaction mixture was reduced to˜ half the volume by evaporation under reduced pressure and was then acidified with 6 M aqueous hydrochloric acid. The resulting precipitate was collected by filtration, heated in dioxan (50-100 ml) and filtered. This procedure was then repeated twice. The resulting solid was added to water just below the boiling point and stirred in order to dissolve water soluble by-products. The insoluble material was collected by filtration, washed with dioxan and dried to give (±)-cis-1-(10-bromophenanthrene-2-carbonyl)piperazine-2,3-dicarboxylic acid (5) as a white solid. 1H NMR (270 MHz, D2O/NaOD):—2.5-3.4 (m, 4H), 4.3 (d, 0.5 H), 5.5 (d, 0.5 H), 7.2-7.6 (m), 7.65-7.8 (m), 7.75 (s) 7.95-8.2 (m), 8.1 (s) and 8.25-8.5 (m).

Provenance & Evidence