Method for inhibiting and controlling viral growth

A method for substantially inhibiting HIV or the activation of HIV in an HIV-infected individual or suppressing the immune system which comprises administering a therapeutically effective amount of a compound of the following formula:

• ##STR3## or a pharmaceutically acceptable acid addition salt thereof, wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are each independently hydrogen, hydroxy, halogen, lower alkyl, lower alkoxy, benzyloxy, trifluoromethyl, nitro, or -NR.sub.8 R.sub.9, in which R.sub.8 and R.sub.9 are each independently hydrogen or lower alkyl;
• R.sub.5 and R.sub.6 are each independently hydrogen, lower alkyl or phenyl;
• X is O, S(O).sub.n or NR.sub.7 ;
• Y is O, S(O).sub.n or NR.sub.8 ;
• R.sub.7 is hydrogen, lower alkyl, phenyl, benzyl, CH.sub.2 OR.sub.8 or lower alkyl, phenyl, benzyl substituted with halo;
• R.sub.8 is hydrogen, lower alkyl or phenyl;
• n is an integer of 0, 1 or 2;
• with the provisos that
• 1) when X is NH, Y is NH, R.sub.1 is H, R.sub.3 is H and R.sub.4 is Br, R.sub.2 is not methyl;
• 2) when X is NH, Y is NH, R.sub.1, R.sub.3 and R.sub.4 are H, R.sub.2 is not methoxy or ethoxy, and
• 3) when X is NH, Y is S, at least one of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is not H.