| abstract |
Piperazinediones of the general formula I wherein R 1 is n. is a group of the general formula - (NH) -, wherein the t is 0 or 1 and R is 3. (i) a group of formula A wherein v = 0 when t is 1 and v = 1 when t = 0; and n = 0 or 1 and m = 0, 1, 2 or 3, at least n or m is not 0 and either (a) R.sup.4 is n. is H or alkyl; the alkyl group being substituted by one or two phenyl groups, the phenyl group or groups being substituted; or (b) R.sup.4. and R.sup.5.n. together with the nitrogen atom, they are formed, a heterocyclic group selected from the groups of formulas 1, 2, 3 and 4, wherein R 6 is n. and R.sup.7.n. they are the same or different and are H or alkoxy, or co-methylenedioxy; Y is O or -NR.sup.8 where R.sup.8 is n. is alkyl or phenyl substituted with substituted CF 3; (ii) a group of formula B wherein p = 1 or 2 and Z is C.sub.2.n.-C.sub.6. alkenyl or phenyl optionally substituted; and (iii) general formula group \ t |