Abstract
Dihydropyrimidinones, such as 1, represent a novel class of alpha(1a) adrenoceptor antagonists with potential for the treatment of benign prostatic hyperplasia (BPH) (see part 1 of this series). Analysis of the metabolites of 1 revealed that 4-methoxycarbonyl-4-phenylpiperidine is formed as the major metabolite and is an agonist at the mu-opioid receptor. To circumvent any potential liability resulting from the metabolite, we decided to identify alternate templates devoid of agonist activity at the mu-opioid receptor to replace the 4-methoxycarbonyl-4-phenylpiperidine moiety. The present study describes the synthesis and SAR of dihydropyrimidinones linked to substituted 4-phenylpiperazine containing side chains. Compound (+)-38 was identified as a lead compound with a binding and functional profile comparable to that of 1. The putative metabolite 2-carboxamidophenylpiperazine has negligible affinity for the mu-opioid receptor.
MeSH terms
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Adrenergic alpha-Antagonists / chemical synthesis*
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Adrenergic alpha-Antagonists / chemistry
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Adrenergic alpha-Antagonists / metabolism
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Adrenergic alpha-Antagonists / pharmacology
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Animals
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Binding, Competitive
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Biological Availability
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Dogs
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Drug Design
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GTP-Binding Proteins / metabolism
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Half-Life
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Humans
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In Vitro Techniques
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Male
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Piperazines / chemical synthesis*
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Piperazines / chemistry
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Piperazines / metabolism
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Piperazines / pharmacology
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Prostate / metabolism
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Pyrimidinones / chemical synthesis*
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Pyrimidinones / chemistry
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Pyrimidinones / metabolism
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Pyrimidinones / pharmacology
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Rats
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Receptors, Adrenergic, alpha-1 / metabolism*
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Receptors, Opioid, mu / agonists
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Recombinant Proteins / metabolism
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Stereoisomerism
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Structure-Activity Relationship
Substances
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1,2,3,6-tetrahydro-1-(N-((4-(2-nitrophenyl)piperazin-1-yl)propyl)carboxamido)-4-methyl-6-(3,4-difluorophenyl)-2-oxopyrimidine
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ADRA1A protein, human
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Adrenergic alpha-Antagonists
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Piperazines
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Pyrimidinones
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Receptors, Adrenergic, alpha-1
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Receptors, Opioid, mu
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Recombinant Proteins
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GTP-Binding Proteins