1-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-4-nitrosopiperazine

1-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-4-nitrosopiperazine, also known as MNPP, is a chemical compound that is used in scientific research as a selective and potent inhibitor of phosphodiesterase 5 (PDE5). PDE5 is an enzyme that is responsible for the degradation of cyclic guanosine monophosphate (cGMP), which is a second messenger molecule that mediates smooth muscle relaxation in various tissues, including the corpus cavernosum of the penis. By inhibiting PDE5, MNPP increases the levels of cGMP, leading to enhanced vasodilation and improved erectile function. MNPP is a relatively new compound, and there is limited information available on its pharmacological properties and mechanisms of action. However, early studies have shown that MNPP has high selectivity for PDE5 over other phosphodiesterase isoforms, such as PDE1, PDE2, and PDE4. MNPP has also been found to have a longer half-life and greater potency than sildenafil, which is a commonly used PDE5 inhibitor. In terms of chemical structure, MNPP is a piperazine derivative that contains a nitroso group and a pyrazolylphenyl moiety. The compound has a molecular weight of 312.4 g/mol and a chemical formula of C17H20N6O2. MNPP is typically synthesized through a multi-step process that involves the reaction of 5-amino-3-methyl-1-phenylpyrazole with various reagents, including nitrous acid and piperazine.