Therapeutic phenoxyalklpyridazines and intermediates therefor

A compound of formula:

• ##STR50## wherein:
• R.sub.1 and R.sub.2 are independently hydrogen, halo, alkyl, alkenyl, alkoxy, hydroxy, hydroxyalkyl, hydroxyhaloalkyl, alkoxyalkyl, alkylthio, alkynyl, amino, nitro, cyano, difluoromethyl, trifluoromethyl, hydroxyalkoxy, alkylthioalkyl, alkylsulfinylalkyl, alkylsulfonylalkyl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, alkoxycarbonyl, carboxy or cyanomethyl;
• Y is alkylene of 3 to 9 carbon atoms;
• R.sub.3 and R.sub.4 are independently hydrogen, alkyl, alkoxy, hydroxy, cycloalkyl, hydroxyalkyl, hydroxyhaloalkyl, alkoxyalkyl, hydroxyalkoxy, alkylthioalkyl, alkanoyl, alkanoyloxy, alkylsulfinylalkyl, alkylsulfonylalkyl, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, alkoxycarbonyl, carboxy, cyanomethyl, fluoroalkyl, cyano, phenyl, alkynyl, alkoxy or halo;
• R.sub.5 is alkoxycarbonyl, alkyltetrazolyl, phenyl or a heterocycle selected from the group consisting of benzoxazolyl, benzathiazolyl, thiadiazolyl, imidazolyl, dihydroimidazolyl, oxazolyl, thiazolyl, oxadiazolyl, pyrazolyl, oxazolinyl, isoxazolyl, isothiazolyl, furyl, triazolyl, thiophenyl, pyridyl, pyrimidinyl, pyrazinyl and pyfidazinyl wherein said phenyl and said heterocycle may be substituted with alkyl, alkoxyalkyl, cycloalkyl, hydroxyalkyl, alkoxy, hydroxy, furyl, thienyl, or halo, or a pharmaceutically acceptable acid addition salt thereof;
• or an N-oxide thereof.