matter aspect of the invention are the pharmaceutically acceptable acid addition salts of the foregoing compounds the substituted phenyl group represented by r 4 has from 1 to 3 substituents at the benzene ring by way of example the substituent can be an alkylacyl group an acylamide group an alkoxy group an alkoxycarbonyl group an alkoxycarbonylmethyl group where the alkyl moiety in each of these substituents has from 1 to 4 carbon atoms a cyano group a carbamoylmethyl group a carbamoyl group a hydroxy group a carboxymethyl group a hydrazinocarbonylmethyl group or a halogen atom the substituent in the substituted phenoxymethyl group the substituted heterocyclyl group or the substituted heterocyclyloxymethyl group represented by r 4 can be any of those suitable as substituents for the substituted phenyl group as illustrated above the number of substituents at the benzene or heterocyclyl ring for these groups is also from 1 to 3 the acid addition salts of the present invention include inorganic acid addition salts such as hydrochloride sulfate hydrobromide phosphate and the like and organic acid addition salts such as acetate maleate fumarate tartrate citrate oxalate benzoate and the like the compounds of the present invention can be produced by the following methods str6 wherein.