Pyridazino(4,5-b)indolizines

Abstract

The compound of the formula: ##STR1## in which R.sup.1 is hydrogen, alkoxy, cyano, halo, nitro, amino, or mono- or dialkylamino; R.sup.2 is hydrogen, alkyl, phenyl, benzyl, 2-thienyl, 3-thienyl or 2-,3- or 4-pyridinyl; R.sup.3 is hydrogen, alkyl or phenyl; R.sup.4 is N-methyl-pyrrolidin-2yl, 2-, 3- or 4-pyridinyl, 3-quinuclidinyl or ##STR2## where n is 1 to 5; m is 0 to 3; and R.sup.8 is hydrogen or alkyl of 1 to 6 carbon atoms; or R.sup.4 is ##STR3## wherein: (a) n is 2, R.sup.5 taken with R.sup.3 is ethylene and R.sup.6 is --CHO, alkyl, unsubstituted or substituted phenyl, pyrimidinyl, pyridinyl, or pyrazinyl, where the substituents are alkyl, alkoxyl, halo, cyano, nitro or trifluoromethyl; (b) n is 1 to 5, and R.sup.5 and R.sup.6 taken together are polymethylene which may be alkyl substituted or R.sup.5 nd R.sup.6 are morpholino, 3-azabicyclo[3.2.2]nonan-3-yl, pyrrol-1-yl, pyrrolidin-2-on-1-ytl, pyrrolidin-2-thion-1-yl, imidazol-1-yl, alkyl-piperidin-1-yl or a piperazin-1-yl moiety in the 4-position of which is hydrogen, --CHO, alkyl or unsubstituted or substituted phenyl, pyrimidinyl, pyridinyl, or pyrazinyl, alkoxy, halo, cyano, nitro or trifluoromethyl; or (c) n is 1 to 5, and R.sup.5 and R.sup.6 are, independently, hydrogen, alkyl, phenyl, 3-quinuclidinyl, 2-adamantyl, bicyclo[3.2.1]octan-1-yl, bicyclo[3.3.1]nonan-9-yl or 2-,3- or 4- pyridinyl; or a pharmaceutically acceptable salt thereof are M.sub.1 receptor agonists useful in treatment of dementias involving the cholinergic system. dd