| abstract |
Analgesic compounds of the formula (I): ##STR1## in which, R 1 R 2 each represents hydrogen or C 1 -C 6 alkyl, or R 1 and R 2 together with the nitrogen atom to which they are attached form a 5-6-membered N-heterocyclic ring optionally having a further O, N, or S heteroatom; E represents methylene; ring A is an unsubstituted or substituted benzene or naphthalene; R 3 and R 4 together represent a group of formula (IV): n n --(CR.sup.a R.sup.a).sub.m --C(=Y)-- (IV) n n wherein R a and R a is C 1 -C 6 alkyl or hydrogen with up to a maximum of 3 alkyl groups, m is 1, 2, or 3, and Y is two hydrogens or oxygens. |