Abstract The synthesis and spectral properties (ir, ms, nmr) of a substituted 2-methyl-2H- pyrazolo [4, 3-d]-pyrimidin-7-one (3), an isomer of Viagra®, are described. The key synthon, 4-amino-1-methyl-5-propyl-3-pyrazolecarboxamide (7), is prepared via the reaction of ethyl 2, 4-dioxoheptanoate with methylhydrazine, followed by cyclization, nitration, amidation, and nitro group reduction. Interaction of 7 with 2-ethoxyben-zoyl chloride yielded the ...
![4-[(2-Ethoxybenzoyl)amino]-1-methyl-5-propyl-1H-pyrazole-3-carboxamide结构式](https://image.chemsrc.com/caspic/451/501120-38-3.png)
![5-(2-Ethoxyphenyl)-2,6-dihydro-2-Methyl-3-propyl-7H-pyrazolo[4,3-d]pyrimidin-7-one结构式](https://image.chemsrc.com/caspic/058/501120-40-7.png)
![4-ethoxy-3-(2-methyl-7-oxo-3-propyl-4H-pyrazolo[4,3-d]pyrimidin-5-yl)benzenesulfonyl chloride结构式](https://image.chemsrc.com/caspic/482/501120-42-9.png)