The present invention provides, in its principal aspect, compounds of the general formula: ##STR1## where A is --NHCO--, --N(CH.sub.3)--CO--, --NHCH.sub.2 --, --N(CH.sub.3)--CH.sub.2 --, --COCH.sub.2 --, --CH.sub.2 CH.sub.2 --, or --CH(OH)CH.sub.2 --, X is H, CH.sub.3, NH.sub.2, NH(CH.sub.3), N(CH.sub.3).sub.2, OCH.sub.3, or SH; R.sub.2 is hydrogen or a methyl or ethyl group; R.sub.3 is hydrogen or a methyl or ehtyl group; n is 0, 1, 2, 3, 4, 5 or 6; R.sub.1 is selected from the group consisting of (a) alkyl; (b) C.sub.3 to C.sub.8 cycloalkyl; (c) phenyl or substituted phenyl; (d) heterocyclic; (e) decahydronaphthalene and (f) octahydroindane; or R.sub.1 and X may be taken together to denote a 5,6 or 6,6 saturated bicycle ring structure. The compounds of the present invention have H3 histamine receptor antagonist activity. This invention also provides pharmaceutical compositions comprising a pharmaceutically acceptable carrier in combination with an effective amount of a compound of formula 1.0. The present invention also provides a method of treating conditions in which antagonism of histamine H3 receptors may of therapeutic importance.