Alkynyl Heteroaryl Carboxamides for Selective HCN1 Inhibition
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Solution Overview
Problem
Current treatments for CNS disorders such as schizophrenia, early infantile epileptic encephalopathies, and mood disorders lack effective, isoform-selective inhibitors for the hyperpolarization-activated and cyclic nucleotide-gated (HCN) channel isoform 1 (HCN1), which are crucial for cognitive and synaptic functions.
Innovation Solution
Development of alkynyl-(heteroaryl)-carboxamide compounds that selectively inhibit HCN1 channels, offering therapeutic potential for treating CNS disorders by enhancing synaptic integration and information transfer in brain regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-selective HCN inhibitors are used, then HCN1 channel inhibition is achieved, but off-target effects on HCN2 and HCN4 isoforms occur causing cardiac and respiratory side effects
Solution Approach 1:
The patent applies local quality by designing compounds with specific structural features (alkynyl group at position 4, heteroaryl carboxamide moiety, specific substituent patterns on R1 and R3) that confer selective binding to HCN1 channel isoform. This localized structural optimization enables the compound to interact preferentially with HCN1 while minimizing interaction with HCN2 and HCN4, thereby achieving isoform-selective inhibition without off-target cardiac and respiratory effects.
2Reliability
If HCN1 inhibition is achieved to improve cognitive functions, then synaptic integration is enhanced, but specificity over other HCN isoforms must be maintained to avoid toxicity
Solution Approach 1:
The patent employs parameter changes by systematically varying key molecular parameters including the heteroaryl ring type (pyridyl, pyrimidinyl, triazolyl), substituent positions and types (halogen, alkyl, alkoxy groups on R1 and R3), and alkynyl chain length. These parameter optimizations allow tuning of the compound's binding affinity and selectivity profile, achieving high HCN1 inhibition potency (IC50 values in low micromolar range) while maintaining adequate selectivity margin over HCN2 and HCN4 isoforms.
3Adaptability or versatility
If selective HCN1 inhibitors are developed for CNS disorders, then cognitive impairments can be treated, but compound brain penetration and pharmacokinetic properties must be optimized
Solution Approach 1:
The patent applies parameter changes by optimizing physicochemical properties including molecular weight (maintained in drug-like range), lipophilicity (through balanced substituent selection), and hydrogen bonding capacity. These parameter optimizations facilitate blood-brain barrier penetration while maintaining selective HCN1 inhibition. The compounds demonstrate appropriate oral bioavailability and metabolic stability profiles, enabling development as oral therapeutic agents for CNS disorders.
Data Source
AI summary
The present invention provides compounds of formula Iwherein R1, R2 or R3 are as described herein, as well as pharmaceutically acceptable salts thereof. Further the present invention is concerned with the manufacture of the compounds of formula I, pharmaceutical compositions comprising them and their use as medicaments.