Quinazoline-4(3H)-one-7-carboxamide Derivatives as Human Soluble Epoxide Hydrolase Inhibitors with Developable 5-Lipoxygenase Activating Protein Inhibition

Soluble epoxide hydrolase (sEH) metabolizes epoxyeicosatrienoic acids (EETs), which are endowed with beneficial biological activities as they reduce inflammation, regulate endothelial tone, improve mitochondrial function, and decrease oxidative stress. Therefore, inhibition of sEH for maintaining high EET levels is implicated as a new therapeutic modality with broad clinical applications for metabolic, renal, and cardiovascular disorders. In our search for new sEH inhibitors, we designed and synthesized novel amide analogues of the quinazolinone-7-carboxylic acid derivative 5, a previously discovered 5-lipoxygenase-activating protein (FLAP) inhibitor, to evaluate their potential for inhibiting sEH. As a result, we identified new quinazolinone-7-carboxamides that demonstrated selective sEH inhibition with decreased FLAP inhibitor properties. The tractable SAR results indicated that the amide and thiobenzyl fragments flanking the quinazolinone nucleus are critical features governing the potent sEH inhibition, and compounds 34, 35, 37, and 43 inhibited the sEH activity with IC50 values of 0.30–0.66 μM. Compound 34 also inhibited the FLAP-mediated leukotriene biosynthesis (IC50 = 2.91 μM). In conclusion, quinazolinone-7-carboxamides can be regarded as novel lead structures, and newer analogues with improved efficiency against sEH along with or without FLAP inhibition can be generated.


Table of Contents
. 1
Pyridine was evaporated and reaction mixture was diluted with water. The solid was filtered off under vacuum and dried. The crude product was washed with ethyl acetate. Yield 66%; mp >300 °C (decomp). 1

2-amino-4-(methoxycarbonyl)benzoic acid (16)
To a solution of Compound 15 (9 mmol, 1 eq) in MeOH (4 mL), chloromethylsilane (13.5 mmol, 1.5 eq) was added and refluxed for 4 hours. After cooling at rt, the reaction mixture was concentrated and saturated aqueous solution of K2CO3 were added, and the solution was extracted with ethyl acetate. The aqueous layer was acidified at pH 5 with acetic acid and extracted with ethyl acetate. The organic layer was dried, filtered, and evaporated. The crude was used in the next step. Yield 80%; mp 218.2-220.2°C. HRMS m/z calculated for C9H10NO4 [M+H] + 196.0610, found 196.0617. CAS #85743-02-8.
The reaction mixture was then concentrated in vacuo. The obtained methyl-3-amino-4-(chlorocarbonyl) benzoate was used in the next step.
Step 2: Methyl-3-amino-4-(chlorocarbonyl) benzoate (5.584 mmol, 1 eq) was dissolved in acetone (4 mL) and added dropwise to a suspension of NH4SCN (437.8 mg, 5.752 mmol, 1.03 eq) in acetone (2mL). The reaction mixture was stirred at rt for 2 hours and filtered off under vacuum. This solid was then suspended in an aqueous solution of NaOH (10% w/w, 5 mL), stirred and filtered off under vacuum. Water was added to the residue and mixture was acidified to pH 2 with aqueous 2N HCl, the solid was filtered under vacuum. The compound was used in the next  [M+H] + 292.1120, found: 292.1132.

Method B: General synthesis method for the alkylation of quinazolinone-7-carboxylic acids
Compound 17 (1.5 mmol, 1 eq) was dissolved in EtOH (3 mL) and 1N NaOH (1.5 mL), appropriate benzyl bromide derivate (1.5 mmol, 1 eq) was added dropwise and refluxed for 2 hours. The mixture was diluted with water and acidified with 2N HCl to pH 3. The solid was filtered under vacuum. The compounds were used in the next step.