MBCQ is a potent and selective cGMP-specific phosphodiesterase (PDE V; PDE5) inhibitor with an IC₅₀ of 19 nM. MBCQ lacks inhibitory activity toward other PDE isozymes (all IC₅₀s>100 μM). MBCQ dilates coronary arteries via specific inhibition of cGMP-PDE^{[1] [2] [3]} .

MBCQ (compound 3d) induces relaxation of isolated porcine coronary arteries precontracted with prostaglandin F2α (PGF2α; EC₅₀=190 nM)^[1] . 
MBCQ (0.01-10 μM; 10 min) inhibits Carbachol (10 μM)-induced contractions in a concentration-dependent manner in rat ileal smooth muscle^[3] . 

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

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Room temperature in continental US; may vary elsewhere.

• [1]. Y Takase, et al. Cyclic GMP phosphodiesterase inhibitors. 2. Requirement of 6-substitution of quinazoline derivatives for potent and selective inhibitory activity. J Med Chem. 1994 Jun 24;37(13):2106-11.

  [2]. Jeffery D MacPherson, et al. Inhibition of phosphodiesterase 5 selectively reverses nitrate tolerance in the venous circulation J Pharmacol Exp Ther. 2006 Apr;317(1):188-95.

  [3]. Takeharu Kaneda, et al. Lack of cyclic nucleotide regulation of MBCQ-induced relaxation of rat ileal smooth muscle. J Smooth Muscle Res. 2003 Jun;39(3):47-54.