- Inhibitors of Blood Platelet cAMP Phosphodiesterase. 3. 1,3-Dihydro-2H-imidazoquinolin-2-one Derivatives with Enhanced Aqueous Solubility
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Two series of 1,3-dihydro-2H-imidazoquinolin-2-one derivatives incorporating an additional site for acid salt formation were synthesized and evaluated as inhibitors of human blood platelet cAMP phosphodiesterase (PDE) and ADP-induced platelet aggregation.The objective of this study was to identify compounds that blended potent biological activity with a satisfactory level of aqueous solubility.From a series of 7-aminoimidazoquinolin-2-ones, biological and physical properties were optimally combined in the 1-piperidinyl derivative 11c.However, this compound offered no significant advantage over earlier studied compounds as an antithrombotic agent in an animal model of small vessel thrombosis.A series of 7-alkoxy alkanoic piperazinamide derivatives, in which the additional basic nitrogen atom was remote from the heterocyclic nucleus and accomodated in a secondary binding region of the cAMP PDE enzyme, demonstrated greater intrinsic cAMP PDE inhibitory activity.Structural modifications of this series focused on variation of the piperazine substituent and side-chain length.The lipophilicity of the N-substituent influenced biological potency and aqueous solubility, with substituents of seven carbon atoms or less generally providing acceptable solubility properties.The N-(cyclohexylmethyl)piperazinamide 21h was identified from this series of compounds as a potent inhibitor of platelet cAMP PDE, IC50 = 0.4 nM and ADP-induced platelet aggregation, IC50 = 0.51 μM after a 3-min exposure and 0.1 μM after a 15-min exposure of platelet-rich plasma to the drug.Evaluation of 21h and representative analogues in vivo using a rabbit model of small vessel thrombosis revealed significantly greater antithrombotic efficacy compared to that of previously studied compounds with similar intrinsic biological activity measured in vitro but inferior aqueous solubility.
- Meanwell, Nicholas A.,Dennis, Ronald D.,Roth, Herbert R.,Rosenfeld, Michael J.,Smith, Edward C. R.,et al.
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p. 2688 - 2696
(2007/10/02)
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- 7-amino-1,3-dihydro-2H-imidazo[4,5-b]quinolin 2-ones and method for inhibiting phosphodiesterase and blood platelet aggregation
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Novel series of 2,3-dihydro-2-oxo-1H-imidazo[4,5-b]quinolinyl amine derivatives of Formula STR1 wherein R1 is hydrogen, lower alkyl; R2 is hydrogen, lower alkyl, lower alkoxy, halogen; R3 is hydrogen, lower alkyl; R4 is hydrogen, lower alkyl, alkanoyl, phenylalkanoyl wherein phenyl is optionally substituted with halogen, lower alkyl, lower alkoxy; R3 and R4 are joined together to form morpholinyl, piperidinyl or pyrrolidinyl optionally substituted with --CO2 R5 or STR2 wherein R5 is hydrogen or lower alkyl, and R6 is hydrogen, lower alkyl, cycloalkyl; 4-R7 -piperazinyl wherein R7 is --CO2 R8 wherein R8 is lower alkyl, phenyl optionally substituted with up to 2 halogen, lower alkyl or lower alkoxy; phenylalkanoyl of 7 to 10 carbon wherein phenyl is unsubstituted or independently substituted with up to 2 halogen, lower alkyl, lower alkoxy. The compounds are cyclic AMP phosphodiesterase inhibitors and are particularly useful as inhibitors of blood platelet aggregation and/or as cardiotonic agents.
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- Piperazinylcarbostyril compounds
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A piperazinylcarbostyril compound of the formula (I) STR1 wherein R1 represents a hydrogen atom, a lower alkyl group, a lower alkenyl group, a lower alkynyl group, or a phenyl-lower alkyl group; R2 represents a hydrogen atom or a lower alkoxy group; R3 represents a hydrogen atom, a lower alkanoyl group, a furoyl group, a pyridylcarbonyl group, a lower alkanesulfonyl group, a lower alkoxycarbonyl group, a lower alkoxycarbonyl-lower alkyl group, a phenylsulfonyl group which may be substituted with a lower alkyl group on the benzene ring thereof, a lower alkyl group, a lower alkenyl group, a lower alkynyl group, a phenylcarbonyl group, a phenyl-lower alkyl group or a phenyl-lower alkanoyl group where each of said phenylcarbonyl group, phenyl-lower alkyl group and phenyl-lower alkanoyl group may be substituted with 1 to 3 of a lower alkoxy group, a halogen atom, a lower alkyl group, a cyano group, a nitro group, an amino group, a hydroxy group, a lower alkanoylamino group, a lower alkylthio group and a lower alkanoyloxy group, or with a lower alkylenedioxy group on the benzene ring thereof; and the bonding between the 3- and 4-positions of the carbostyril nucleus is a single bond or a double bond; or its pharmaceutically acceptable salt, useful as a cardiotonic agent.
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