Cost-effective Technique Brings HIV Treatment Within Everyone’s Reach
Dr. Limei Jin's team developed a short, scalable route from a cheap commodity chemical to a key building block of the HIV drug lenacapavir, avoiding column purification and hydrogen fluoride.
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The effort to find more affordable and scalable ways to make medicines has taken a big step forward with a new method for producing 7-bromo-4-chloro-1H-indazol-3-amine (3). This substance is an essential material needed to synthesize Lenacapavir, a powerful new treatment for the human immunodeficiency virus (HIV). In research led by Dr. Limei Jin, the team at the Medicines for All Institute, Virginia Commonwealth University, developed this innovative synthetic route. Their work was shared in the journal Molecules.
The new process focuses on reducing costs and making production easier to scale up. It uses a starting material called 2,6-dichlorobenzonitrile (1), which is an inexpensive commodity chemical. The method involves two main steps: selective bromination to provide intermediate 2 and then generating the critical 3-aminoindazole ring with hydrazine. The new process avoids the need for costly chemicals and complex purification steps like column chromatography. As such, the new synthetic method is more favorable for economical, large-scale production. “We wanted to simplify the production process and make it more accessible,” explained Dr. Jin.
As part of the work from the team at the Medicines for All Institute, it was shown that the chemistry could be accomplished on a large scale. The team demonstrated that the process could be used to produce sizable batches of the 7-bromo-4-chloro-1H-indazol-3-amine (3) with high purity. Previously, compound 3 could only be prepared from an expensive starting material using a process that released a hazardous by-product (hydrogen fluoride, HF). The new chemistry makes the manufacturing process safer and more reliable.
The importance of this improvement goes beyond cutting costs. Lenacapavir is highly effective at targeting HIV proteins, offering a new type of long-lasting treatment for the virus. Proteins are molecules that perform essential functions in cells, and in this case, the drug blocks the action of HIV capsid proteins to stop the virus from multiplying. “This work provides a sustainable way to produce one of the key intermediates of this life-saving medicine, potentially benefiting countless people worldwide,” said Dr. Jin.
The Medicines for All Institute synthesis also utilizes an environmentally friendly approach. The solvent used in the 3-aminoindazole ring formation is 2-methyltetrahydrofuran, which is considered a biorenewable solvent. Two chemical reaction steps are used in the process and they were both optimized to minimize environmental impact. This aligns with the growing demand for greener practices in drug manufacturing.
Looking ahead, this method has the potential to revolutionize how other drugs are made, especially those that require complex structures like those found in Lenacapavir. The Medicines for All Institute remains committed to developing cost-effective solutions to address global health needs. The synthesis of 7-bromo-4-chloro-1H-indazol-3-amine (3) is an example of this commitment to lower the cost of pharmaceutical synthesis.
About the researchers
Journal reference
Asad, N., Lyons, M., Muniz Machado Rodrigues, S., et al. “Practical Synthesis of 7-Bromo-4-chloro-1H-indazol-3-amine: An Important Intermediate to Lenacapavir.” Molecules, 2024. DOI: https://doi.org/10.3390/molecules29122705







