Anti-hypertensive chromanol derivatives

A compound of the formula:

• ##STR9## or a pharmaceutically acceptable salt or ester thereof, wherein R.sub.1 is hydrogen or lower alkyl;
• R.sub.2 is hydrogen or lower alkyl;
• R.sub.3 is hydrogen or lower alkyl;
• R.sub.4 is hydrogen or lower alkyl;
• R.sub.5 is lower alkyl or alkyl of 3 to 5 carbon atoms terminally substituted by chlorine;
• or R.sub.4 and R.sub.5 are joined so that together with the nitrogen atom to which they are attached they form a 6- or 7-membered saturated heterocyclic ring containing said nitrogen atom as the sole hetero atom or a 5-membered saturated heterocyclic ring optionally containing an oxygen or sulphur atom as an additional hetero atom;
• R.sub.6 is amino, carboxylic acylamino of up to 3 carbon atoms, alkylamino of up to 3 carbon atoms, or dialkylamino of up to 3 carbon atoms in each alkyl moiety;
• R.sub.7 is nitro or cyano;
• and
• the NR.sub.4 R.sub.5 and OR.sub.3 groups are trans.