the invention is directed to methods for selectively blocking u03b1 1a receptors by delivering in the environment of said receptors e g to the extracellular medium or by administering to a mammal possessing said receptors an effective amount of the compounds of the invention the invention will now be illustrated by the following non limiting examples scheme i a mixture of 2 5 dioxopyrrolidine 0 500 g 5 mmol 1 4 4 fluorophenyl piperazin 1 yl 3 chloropropane 1 28 g 5 mmol potassium carbonate 0 502 g 3 75 mmol and tetrabutylammonium bromide 0 322 g 1 mmol in acetone 25 ml was refluxed for 16 hours at 80 u00b0 c with stirring the solvent was evaporated off in vacuo and the residue was suspended in water 80 ml the aqueous solution was extracted with chloroform 3 u00d7 50 ml and the organic layers combined washed with water 2 u00d7 50 ml dried over na 2 so 4 and evaporated in vacuo to give the title compound the product was purified by column chromatography over flash silica gel using chloroform methanol 98 2 as eluent yield 1 00 g 65 oil scheme il 1 amino 3 4 4 fluorophenyl piperazin 1 yl propane 0 700 g 2 95 mmol and succinic anhydride 0 295 g 2 95 mmol were refluxed in pyridine 10 ml for 10 hours acetic anhydride.