Learn about Avanafil

A monocarboxylic acid amide obtained by formal condensation of the carboxy group of 4-[(3-chloro-4-methoxybenzyl)amino]-2-[(2S)-2-(hydroxymethyl)pyrrolidin-1-yl]pyrimidine-5-carboxylic acid with the amino group of pyrimidin-2-ylmethylamine Used for treatment of erectile dysfunction.

Avanafil was originally discovered at Tanabe Seiyaku (now Mitsubishi Tanabe). JW Pharmaceutical (previously Choongwae Pharma) and VIVUS have since developed and launched avanafil, which is an oral PDE5 inhibitor for the treatment of erectile dysfunction (ED). Although many marketed PDE5 inhibitors (e.g. sildenafil, vardenafil and tadalafil) are available for the treatment of ED, many patients are still unable to achieve the desired results and experience undesired side-effects with these existing medications. As such, second-generation PDE5 inhibitors with enhanced PDE5 selectivity, shorter systemic half-lives, and improved tolerability are desired. Developed to meet these criteria, Avanafil exhibited good oral bioavailability and PDE5 selectivity in both preclinical studies and clinical trials. Avanafil had a short onset of action (35 min) and short half-life (1.5 h).

The synthesis presented is based on the published patent procedure and is outlined in the scheme. Commercially available 4-chloro-2-(methylsulfanyl)pyrimidine- 5-carboxylic acid ethyl ester (25) was treated with 3- chloro-4-methoxybenzylamine (26) and triethylamine at room temperature to give 4-benzylaminopyrimidine derivative 27 in 96% yield. Sulfide 27 was then oxidized with m-chloroperbenzoic acid (m-CPBA), followed bytreatment with L-prolinol and triethylamine to afford ethyl pyrimidinate 28 in 83% yield. This ester was then saponified with 10% sodium hydroxide to give pyrimidine- 5-carboxylic acid 29 in 80% yield, which then underwent conventional amide bond formation using 2-(aminomethyl) pyrimidine (29a), N-(3-dimethylaminopropal)-N0-ethylcarbodiimide hydrochloride (EDCI) and 1-hydroxybenzotriazole hydrate (HOBt) to give avanafil (IV) in 83% yield.