| abstract |
Compounds useful as cardiotonic agents are 1-R-3-Q-5-PY-2(1H)-pyridinones (I) where R is hydrogen, lower-alkyl or lower-hydroxyalkyl, Q is amino (preferred), lower-alkylamino, di-(lower-alkyl)amino or NHAc, Ac is lower-alkanoyl or lower-carbalkoxy, and PY is 4- or 3- or 2-pyridinyl or 4- or 3- or 2-pyridinyl having one or two lower-alkyl substituents. The corresponding compounds where Q is nitro, carbamyl, cyano, halo or hydrogen are useful as intermediates and those where Q is hydrogen or cyano also are useful as cardiotonic agents. Said compounds are prepared: by reacting α-PY-β-(R 1 R 2 N)acrolein (II) with malonamide to produce 1,2-dihydro-2-oxo-5-PY-nicotinamide (Ia) and reacting Ia with a reagent capable of converting carbamyl to amino to produce 3-amino-5-PY-2(1H)-pyridinone (Ib); by reacting II or α-PY-malonaldehyde (II') with α-cyanoacetamide to produce 1,2-dihydro-2-oxo-5-PY-nicotinonitrile (III) and partially hydrolyzing III to produce Ia; and, by heating 1,2-dihydro-2-oxo-5-PY-nicotinic acid (IV) with a mixture of concentrated sulfuric acid and concentrated nitric acid to produce 3-nitro-5-PY-2(1H)-pyridinone (Ic) and then either reducing Ic to produce Ib or first reacting Ic with an alkylating agent to produce 1-R'-3-nitro-5-PY-2(1H)-pyridinone (Id) and reducing Id to produce 1-R'-3-amino-5-PY-2(1H)-pyridinone (Ib) where R' is lower-alkyl or lower-hydroxyalkyl. Other derivatives of I where Q is amino are shown. |