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Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
New bronchodilators. II. 3H-imidazo[4,5-c]quinolin-4(5H)-ones
F Suzuki1, T Kuroda, H Hayashi
1Pharmaceutical Research Laboratories, Kyowa Hakko Kogyo Co., Ltd., Shizuoka, Japan.
Chemical & Pharmaceutical Bulletin
|December 1, 1992
Summary
Novel imidazoquinolinone derivatives were synthesized and tested for bronchodilatory effects. The compound 5-ethyl-3-methyl-3H-imidazo[4,5-c]quinolin-4(5H)-one demonstrated significant in vivo activity, outperforming theophylline.
Area of Science:
- Medicinal Chemistry
- Pharmacology
- Organic Synthesis
Background:
- Asthma and bronchospasm are significant respiratory conditions requiring effective bronchodilatory treatments.
- Imidazo[4,5-c]quinolin-4(5H)-one scaffold represents a potential pharmacophore for developing novel therapeutic agents.
Purpose of the Study:
- To synthesize and characterize a series of novel 3-substituted imidazo[4,5-c]quinolin-4(5H)-one derivatives.
- To evaluate the bronchodilatory activity of these novel compounds in vitro and in vivo.
- To identify structure-activity relationships guiding the development of potent bronchodilators.
Main Methods:
- Synthesis of imidazo[4,5-c]quinolin-4(5H)-ones via reaction with electrophiles under basic conditions.
- In vitro evaluation using the Schultz-Dale reaction on guinea-pig trachea.
- In vivo assessment of protective effects against antigen inhalation-induced bronchospasm in guinea-pigs.
Main Results:
- A series of 3-substituted imidazo[4,5-c]quinolin-4(5H)-ones (2a-w) were successfully synthesized.
- Short alkyl chains (methyl, ethyl) at the 3-position were crucial for potent bronchodilatory activity, particularly in vivo.
- 5-Ethyl-3-methyl-3H-imidazo[4,5-c]quinolin-4(5H)-one (21) showed the highest in vivo potency, exceeding theophylline by at least fivefold.
Conclusions:
- The synthesized imidazoquinolinone derivatives hold promise as novel bronchodilatory agents.
- Structural modifications, specifically short alkyl chains at the 3-position, significantly enhance in vivo bronchodilatory efficacy.
- Compound 21 represents a lead candidate for further development in the treatment of bronchospastic disorders.
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