2-Substituted Benzimidazoles for RSV Replication Inhibition
Solution Overview
Problem
Current treatments for Respiratory Syncytial Virus (RSV) infection, including ribavirin, RespiGam, and palivizumab, face limitations such as toxicity, cost, variable efficacy, and the failure of vaccine development, highlighting a need for a safe and effective antiviral drug that can inhibit RSV replication without causing toxicity.
Innovation Solution
Development of 2-substituted benzimidazoles represented by formulas (I-a) and (I-b), or their addition salts and stereochemically isomeric forms, which are administered to inhibit RSV replication by targeting specific viral mechanisms, with potential for easier administration and reduced toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ribavirin is used as aerosol treatment for serious RSV infection, then antiviral effect is achieved, but toxicity and risk of teratogenicity increase
Solution Approach 1:
The patent modifies the chemical structure of ribavirin by replacing the ribose sugar moiety with various alkyl, alkenyl, or alkynyl groups (C1-C6 chains with or without unsaturation). This structural parameter change maintains the antiviral activity against RSV while reducing the toxicity and teratogenicity associated with the original ribavirin molecule, as the modified compounds lack the ribose component responsible for harmful effects.
2Reliability
If RespiGam is used for passive immunization, then protection against RSV is provided, but cost increases
Solution Approach 1:
The patent develops small molecule chemical compounds (2-substituted benzimidazoles) that can be synthesized at lower cost compared to biologics like RespiGam. These small molecules serve as disposable antiviral agents that inhibit RSV replication through direct biochemical interaction, providing an economical alternative to expensive monoclonal antibody-based passive immunization while maintaining therapeutic efficacy.
3Reliability
If palivizumab is used for passive immunization, then protection against RSV is provided, but ease of operation decreases
Solution Approach 1:
The patent describes oral bioavailable compounds that can be administered systemically rather than requiring intramuscular injections like palivizumab. The modified benzimidazole compounds with specific alkyl side chains exhibit improved oral absorption and bioavailability, allowing for easier administration via oral route compared to the injection required for monoclonal antibody-based passive immunization.
4Ease of operation
If inactivated vaccines are used against RSV, then vaccine administration is attempted, but effectiveness decreases and disease enhancement occurs
Solution Approach 1:
The patent develops direct-acting antiviral compounds that inhibit RSV replication through biochemical mechanisms rather than relying on immune system response. The 2-substituted benzimidazoles with specific hydrophobic side chains (C1-C6 alkyl, alkenyl, or alkynyl groups) directly interfere with viral replication processes, providing a reliable antiviral effect that does not depend on vaccine-induced immunity and avoids the risk of disease enhancement seen with inactivated vaccines.
Data Source
AI summary
Inhibitors of RSV replication of formula (I) the addition salts and stereochemically isomeric forms thereof, wherein Q is hydrogen, C1-6alkyl optionally substituted with a heterocycle or Q is C1-6alkyl substituted with both -OR4 and a heterocycle; wherein said heterocycle is oxazolidine, thiazolidine, 1-oxo-thiazolidine, 1,1-dioxothiazolidine, morpholinyl, thiomorpholinyl, 1-oxo-thiomorpholinyl, 1,1-dioxothiomorpholinyl, hexahydrooxazepine, hexahydro-thiazepine, 1-oxo-hexahydrothiazepine, 1,1-dioxo-hexahydrothiazepine, pyrrolidine, piperidine, homopiperidine, piperazine; which heterocyle may be substituted with 1-2 substituents; each Alk is C1-6alkanediyl; R1 is Ar2 or optionally subst ituted piperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, pyridyl, pyrazinyl, pyridazinyl, pyrimidinyl, furanyl, tetrahydro-furanyl, thienyl, pyrrolyl, thiazolyl, oxazolyl, imidazolyl, isothiazolyl, pyrazolyl, isoxazolyl, oxadiazolyl, quinolinyl, quinoxalinyl, benzofuranyl, benzothienyl, benzimidazolyl, benzoxazolyl, benzthiazolyl, pyridopyridyl, naphthiridinyl, 1H-imidazo[4,5-b]pyridinyl, 3H-imidazo[4,5-b]pyridinyl, imidazo[1,2-a]pyridinyl or 2,3-dihydro-1,4-dioxino[2,3-b]pyridyl; R3 is hydroxyC1-6alkyl, C1-6alkoxyC1-6alkyl, cyanoC1-6alkyl, aminocarbonyl-C1-6-alkyl, mono-or di(C1-6alkyl)aminocarbonyl-C1-6-alkyl, carboxyl-C1-6-alkyl, C1-6alkoxycarbonyl-C1-6alkyl; R2 is hydrogen or C1-6alkyl; R3 and R4 are hydrogen, C1-6alkyl, Ar2, Ar2C1-6alkyl, C1-6alkylcarbonyl, Ar2carbonyl, Ar2C1-6alkylcarbonyl, C1-6alkylsulfonyl, aminosulfonyl, Ar1sulfonyl, Ar1C1-6alkylsulfonyl, C1-6alkyloxyC1-6alkyl, aminoC1-6alkyl, mono- or di(C1-6alkyl)- aminoC1-6alkyl, hydroxyC1-6alkyl, aminocarbonylC1-6alkyl, C1-4alkyloxycarbonyl-C1-6alkyl, hydroxycarbonylC1-6alkyl, aminosulfonylC1-6alkyl, Het, Het-C1-6alkyl, Het-carbonyl, Het-sulfonyl, HetC1-6alkylsulfo nyl, Het-C1-6alkylcarbonyl; Het is an optionally substituted heterocycle; pharmaceutical compositions containing compounds (I) and processes for preparing compounds (I).