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AssigneeSterling Drug Inc.
InventorsGeorge Y. Lesher, William B. Dickinson
Estimating the term…
2-R-4-R'-6-PY-3(2H)-pyridazinones (I) or salts thereof, which are useful as intermediates and some as cardiotonics, are prepared by reacting di-(lower-alkyl) hydroxy[2-oxo-2-PY-ethyl]propanedioate (II) with a hydrazine salt of the formula RNHNH.sub.2.nH.sub.x An (III) to produce lower-alkyl 2,3-dihydro-2-R-3-oxo-6-PY-4-pyridazinecarboxylate (Ia where R' is lower-carbalkoxy) and reacting Ia with hydrazine hydrate or anhydrous hydrazine to produce 2,3-dihydro-2-R-3-oxo-6-PY-4-pyridazinecarboxylic acid hydrazide (Ib where R' is aminocarbamyl), where PY is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two lower-alkyl substituents, R is hydrogen, lower-alkyl or lower-hydroxyalkyl, R' is carbamyl, carboxy, aminocarbamyl or lower-carbalkoxy, n is 1 or 2, x is 1, 2 or 3, and An is an anion of a strong inorganic acid or an organic sulfonic acid. Also shown are: the preparation of II from PY--COCH.sub.3 (IV), the conversion of Ia to Ib (Id where R' is carboxy), and the use of 2-R-4-R"-6-PY-3(2H)-pyridazinones (I where R is lower-alkyl or lower-hydroxyalkyl and R" is carbamyl, aminocarbamyl or lower-carbalkoxy) as cardiotonic agents. Other intermediates are shown.
A 2-R-4-R'-6-PY-3(2H)-pyridazinone having the formula ##STR4## or pharmaceutically-acceptable acid-addition salt thereof, where PY is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two lower-alkyl substituents, R is hydrogen, lower-alkyl or lower-hydroxyalkyl, and R' is carbamyl, carboxy, aminocarbamyl or lower-carbalkoxy.
A cardiotonic composition for increasing cardiac contractility, said composition comprising a pharmaceutically-acceptable inert carrier and, as the active component thereof, an effective amount of a cardiotonic 2-R-4-R"-6-PY-3(2H)-pyridazinone or pharmaceutically-acceptable acid-addition salt thereof where R is lower-alkyl or lower-hydroxyalkyl, PY is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two lower-alkyl substituents, and R" is carbamyl, aminocarbamyl or lower-carbalkoxy.
The method for increasing cardiac contractility in a patient requiring such treatment which comprises administering orally or parenterally in a solid or liquid dosage form to such patient an effective amount of a cardiotonic 2-R-4-R"-6-PY-3(2H)-pyridazinone or pharmaceutically-acceptable acid-addition salt thereof, where R is lower-alkyl or lower-hydroxyalkyl, PY is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two lower-alkyl substituents, and R" is carbamyl, aminocarbamyl or lower-carbalkoxy.
Dependencies are inferred from the claim text.