Pyrimidinedione, pyrimidinetrione, triazinedione and tetrahydroquinazolinedione derivatives as .alpha..sub.1 -adrenergic receptor antagonists

A compound of the formula:

• ##STR15## in which:
• R.sup.2 is chloro, fluoro, hydro, hydroxy, or methyl;
• and
• R.sup.5 is selected from Formula (a) or (b):
• ##STR16## in which:
• R.sup.6 is hydro, methyl, cyclohexylmethyl, pyridylmethyl, pyrazinylmethyl, furylmethyl, thienylmethyl, biphenylmethyl, or a group selected from benzyl and phenyl (which group is optionally further substituted with one to three radicals selected from chloro, fluoro, methyl, or methoxy);
• R.sup.7 is hydro, hydroxymethyl, methyl, or ethyl;
• and
• R.sup.9 is hydro or methyl,
• or a pharmaceutically acceptable salt or N-oxide thereof.