Multistep Continuous Flow Synthesis of Stavudine

Area of Science:

• Organic Chemistry
• Medicinal Chemistry
• Chemical Engineering

Background:

• Stavudine (d4T) is a critical nucleoside analog used in treating Human Immunodeficiency Virus (HIV) and Acquired Immunodeficiency Syndrome (AIDS).
• Traditional synthesis methods for d4T can be lengthy and complex, posing challenges for large-scale production.
• Developing efficient and scalable synthetic routes is crucial for ensuring access to essential antiviral medications.

Purpose of the Study:

• To establish an elegant multistep continuous flow synthesis for stavudine (d4T).
• To optimize the synthesis for high yield, throughput, and reduced reaction times.
• To demonstrate the feasibility of producing d4T without intermediate purification.

Main Methods:

• Utilized a sequential continuous flow reactor system comprising five reactors.
• Employed six chemical transformations starting from 5-methyluridine.
• Implemented single-step and multistep continuous flow synthesis protocols.

Main Results:

• Achieved an average of 97% yield in single-step continuous flow synthesis.
• Demonstrated a throughput of 21.4 g/h per step with a 15.5 min residence time.
• Successfully synthesized d4T in 87% total yield via multistep flow synthesis with a total residence time of 19.9 min and 117 mg/h throughput, without intermediate purification.

Conclusions:

• The developed continuous flow synthesis offers an efficient and scalable method for stavudine (d4T) production.
• This approach significantly reduces synthesis time and complexity compared to batch processes.
• The successful demonstration paves the way for streamlined manufacturing of this vital antiretroviral drug.