The development and production of modern pharmaceuticals are built upon a deep understanding of chemistry and the precise synthesis of complex molecules. Behind every medication lies a journey involving numerous chemical transformations, often starting with specialized intermediates. One such compound, vital to the pharmaceutical industry, is 4-Ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)benzenesulfonyl chloride (CAS: 139756-22-2). This substance is a cornerstone in the synthesis of Sildenafil citrate, a medication widely recognized for its therapeutic benefits.

The chemical identity of this intermediate, C17H19ClN4O4S, with a molecular weight of approximately 410.88 g/mol, reveals a complex structure engineered for specific reactivity. Its properties, such as a melting point typically between 180-182°C, indicate a stable solid form suitable for handling and processing in industrial settings. The density of 1.48 g/cm³ further characterizes its physical nature. These attributes are meticulously controlled by manufacturers to ensure consistent performance in subsequent synthetic steps.

The primary application of 4-Ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)benzenesulfonyl chloride is its role as a key intermediate in the multi-step synthesis of Sildenafil citrate. The sulfonyl chloride functional group is a powerful electrophile, making it an ideal reactant for forming critical bonds within the Sildenafil molecule. The successful and efficient production of Sildenafil relies heavily on the purity and reliable supply of this intermediate.

For pharmaceutical companies, ensuring a consistent supply of high-purity intermediates is paramount. Sourcing from a reputable 4-Ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)benzenesulfonyl chloride manufacturer in China, like NINGBO INNO PHARMCHEM CO.,LTD., provides access to materials that meet rigorous quality standards, often with purity levels exceeding 99%. This commitment to quality ensures that the final API is synthesized effectively and safely, adhering to strict regulatory requirements.

The availability of such critical chemical intermediates not only underpins the production of specific medications but also fuels ongoing research and development in medicinal chemistry. As the pharmaceutical industry continues to evolve, the role of specialized chemical intermediates remains indispensable, driving innovation and ensuring that vital treatments reach those who need them.