1-cyclohexyl-3-[4-[(5-methyl-3-isoxazolyl)sulfamoyl]phenyl]urea

1-Cyclohexyl-3-[4-[(5-methyl-3-isoxazolyl)sulfamoyl]phenyl]urea, often referred to by its shorter name **SU5416**, is a small-molecule drug that acts as a potent and selective **inhibitor of vascular endothelial growth factor receptor (VEGFR) tyrosine kinases**.

Here's why it's important for research:

**1. Anti-angiogenic Potential:**

VEGFRs play a crucial role in angiogenesis, the process of new blood vessel formation. SU5416 blocks the activation of these receptors, inhibiting angiogenesis. This makes it a potential therapeutic agent for:

* **Cancer:** Preventing tumor growth by inhibiting the formation of new blood vessels that supply oxygen and nutrients to the tumor.
* **Ocular Diseases:** Treating diseases like diabetic retinopathy and macular degeneration, where abnormal angiogenesis leads to vision loss.

**2. Research Tool:**

SU5416 has been extensively used as a research tool to study the role of angiogenesis in various biological processes. It provides researchers with a valuable tool to:

* **Investigate the mechanisms of angiogenesis.**
* **Screen for new anti-angiogenic drugs.**
* **Develop models for studying angiogenesis in various diseases.**

**3. Historical Significance:**

SU5416 was one of the first potent and selective VEGFR inhibitors developed. Its discovery paved the way for the development of a new class of anti-angiogenic drugs, significantly impacting the field of cancer treatment and other related fields.

**4. Current Status:**

Although SU5416 itself is not currently approved for clinical use, its development has led to the approval of other VEGFR inhibitors like **sunitinib** and **pazopanib** for treating various cancers.

**Important Considerations:**

* **Toxicity:** Like many targeted therapies, SU5416 can have side effects, including hypertension and bleeding.
* **Resistance:** Tumors can develop resistance to VEGFR inhibitors, highlighting the need for ongoing research to develop new and effective treatments.

Overall, SU5416 is a highly significant compound in the field of anti-angiogenic research. Its discovery and subsequent research have led to important advances in our understanding of angiogenesis and the development of new therapies for a wide range of diseases.