Pyrido[2,1-b]quinazolinecarboxamide derivatives as platelet activating factor antagonists
摘要:
A series of N-[(heteroaryl)alkyl]pyrido[2,1-b]quinazolines were evaluated for their ability to inhibit the binding of radiolabeled platelet activating factor (PAF) to its receptor on dog platelets. The most potent compounds in this series were found to be pyrido[2,1-b]quinazoline-8-carboxamides possessing a four- or six-carbon chain between the carboxamide nitrogen atom and a 3-pyridinyl or 5-pyrimidinyl moiety. Since earlier metabolism studies with pyridoquinazolinecarboxamides suggest that the carboxamide moiety is labile to hydrolysis in vivo, attempts were made to find isosteric replacements for this group. The substitutions examined led to a loss of activity; however, insertion of a methyl group on the carbon atom alpha to the carboxamide nitrogen led to an enantioselective enhancement of potency. (R)-2-(1-Methylethyl)-N-[1-methyl-4-(3-pyridinyl)butyl]-11-oxo-11H- pyrido[2,1-b]quinazoline-8-carboxamide (34) was more potent than the corresponding S enantiomer in the PAF binding assay and was also shown to be more resistant to degradation by amidases present in whole liver homogenates obtained from guinea pig, dog, and squirrel monkey. The corresponding rac-2-(1-methylethyl)-N-[1-methyl-4-(3-pyridinyl)butyl]-11-oxo-11H- pyrido[2,1-b]quinazoline-8-carboxamide (33) was found to inhibit transient PAF-induced thrombocytopenia and decreases in blood pressure in guinea pigs after intravenous or oral administration and to have a duration of action of greater than 5 h after an oral dose of 200 mg/kg. Compound 33 thus represents the prototype of a new class of orally active PAF antagonists.
Pyrido[2,1-b]quinazolinecarboxamide derivatives as platelet activating factor antagonists
摘要:
A series of N-[(heteroaryl)alkyl]pyrido[2,1-b]quinazolines were evaluated for their ability to inhibit the binding of radiolabeled platelet activating factor (PAF) to its receptor on dog platelets. The most potent compounds in this series were found to be pyrido[2,1-b]quinazoline-8-carboxamides possessing a four- or six-carbon chain between the carboxamide nitrogen atom and a 3-pyridinyl or 5-pyrimidinyl moiety. Since earlier metabolism studies with pyridoquinazolinecarboxamides suggest that the carboxamide moiety is labile to hydrolysis in vivo, attempts were made to find isosteric replacements for this group. The substitutions examined led to a loss of activity; however, insertion of a methyl group on the carbon atom alpha to the carboxamide nitrogen led to an enantioselective enhancement of potency. (R)-2-(1-Methylethyl)-N-[1-methyl-4-(3-pyridinyl)butyl]-11-oxo-11H- pyrido[2,1-b]quinazoline-8-carboxamide (34) was more potent than the corresponding S enantiomer in the PAF binding assay and was also shown to be more resistant to degradation by amidases present in whole liver homogenates obtained from guinea pig, dog, and squirrel monkey. The corresponding rac-2-(1-methylethyl)-N-[1-methyl-4-(3-pyridinyl)butyl]-11-oxo-11H- pyrido[2,1-b]quinazoline-8-carboxamide (33) was found to inhibit transient PAF-induced thrombocytopenia and decreases in blood pressure in guinea pigs after intravenous or oral administration and to have a duration of action of greater than 5 h after an oral dose of 200 mg/kg. Compound 33 thus represents the prototype of a new class of orally active PAF antagonists.
Pyrido[2,1-b]quinazoline derivatives useful as agents for treatment of
申请人:Hoffmann-La Roche Inc.
公开号:US04551460A1
公开(公告)日:1985-11-05
Pyrido[2,1-b]quinazoline derivatives of the formulas ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are as hereinafter set forth, are described. The compounds of formulas I and II are useful as agents for the treatment of allergic conditions as well as for the treatment of vascular disorders involving thrombosis.
The invention provides compounds of the general formula (I) ##STR1## and physiologically acceptable salts and solvates thereof, wherein Q represents a chlorine atom or a trifluoromethyl group; X represents a bond, or a C.sub.1-6 alkylene, C.sub.2-6 alkenylene or C.sub.2-6 alkynylene chain, and Y represents a bond, or a C.sub.1-6 alkylene, C.sub.2-6 alkenylene or C.sub.2-6 alkynylene chain with the proviso that the sum total or carbon atoms in the chains X and Y is not more than 10, and the chains XCH.sub.2 and CH.sub.2 Y may each be optionally substituted by one or two C.sub.1-3 alkyl groups, or, when one carbon atom is substituted by two alkyl groups, these may be linked to form an alkylene group; R represents a hydrogen atom or a C.sub.1-3 alkyl group; R.sup.1 and R.sup.2 each represent a hydrogen atom or a C.sub.1-3 alkyl group, with the proviso that the sum total of carbon atoms in R.sup.1 and R.sup.2 is not more than 4; and Het is optionally substituted pyrimidinyl. The compounds have a stimulant action at .beta.-adrenoreceptors and may be used in the treatment of diseases associated with reversible airways obstruction such as asthma and chronic bronchitis.