Hydrochloric Acid → HCID 12899683, compound

Participants

Reaction Steps

19.1 g of 8-(p-toluenesulfonyl)-6,7-dihydro-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid and 12.9 g of piperazine were added to 200 ml of anhydrous dimethyl sulfoxide and the mixture was heated in an autoclave under flow of nitrogen at 10 atm. at a temperature of 150° to 160° C. for 18 hours while stirring. After completion of the reaction, the solvent and excess piperazine were removed under reduced pressure and a mixture of methanol and ethanol was added to the residue. The preicpitates formed were separated by filtration and washed with diethyl ether. The crystals thus-obtained were suspended in a mixture of 200 ml of water and 40 ml of a 10% aqueous hydrochloric acid solution and insoluble materials were removed by filtration. The filtrate was rendered neutral with saturated aqueous solution of sodium bicarbonate and purified through column chromatography using Amberlite LH-20 (a trade name for a product of Tokyo Organic Chemical Industries Ltd.) (eluent: water, ethanol). Recrystallization of the eluate from dimethylformamide gave 2.7 g of 8-(1-piperazinyl)-6,7-dihydro-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid as white needles having a melting point of 267° to 268° C.

Provenance & Evidence