5 PY 6 Q pyridin 2 amines or {HEAD ~ pharmaceutically acceptable acid addition salts} thereof are {TAIL ~ useful cardiotonics}, where Q is hydrogen or lower alkyl, and PY is 4 pyridinyl or 4 pyridinyl having one or two lower alkyl substituents 
5 PY 6 Q pyridin 2 amines or { HEAD ~ pharmaceutically acceptable acid addition salts } thereof are { TAIL ~ useful cardiotonics } , where Q is hydrogen or lower alkyl , and PY is 4 pyridinyl or 4 pyridinyl having one or two lower alkyl substituents
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