1-(2,4-dichlorophenyl)-3-[3-(1-imidazolyl)propyl]urea

1-(2,4-dichlorophenyl)-3-[3-(1-imidazolyl)propyl]urea, also known as **L-687,781**, is a small-molecule compound that acts as a **selective inhibitor of the enzyme histone deacetylase (HDAC)**.

**Here's why it's important for research:**

* **HDACs and their role in disease:** HDACs are enzymes that remove acetyl groups from lysine residues on histone proteins. This process is crucial for regulating gene expression, and dysregulation of HDAC activity is implicated in various diseases, including:
* **Cancer:** HDAC inhibitors can induce apoptosis (programmed cell death) in cancer cells, and are being studied for their potential therapeutic value.
* **Neurological disorders:** HDAC inhibitors have shown promise in treating conditions like Alzheimer's disease and Parkinson's disease by promoting neuroprotection and improving cognitive function.
* **Inflammation and autoimmune disorders:** HDAC inhibitors have anti-inflammatory effects and are being explored for their potential in treating inflammatory bowel disease, rheumatoid arthritis, and other autoimmune conditions.

* **L-687,781 as a research tool:** L-687,781 is a valuable research tool because it is:
* **Selective:** It preferentially inhibits Class I HDACs (HDAC1, HDAC2, HDAC3, and HDAC8), which are particularly important in regulating gene expression in various cellular processes.
* **Potent:** It exhibits significant inhibitory activity against HDACs, allowing for its use in studying the biological effects of HDAC inhibition.
* **Cell-permeable:** It can easily enter cells, enabling its use in both in vitro and in vivo studies.

* **Contributions to understanding HDAC biology:** L-687,781 has been instrumental in:
* **Identifying and characterizing specific HDACs:** It has helped researchers understand the functions and roles of different HDAC isoforms.
* **Developing new drug candidates:** L-687,781 has served as a lead compound for the development of novel HDAC inhibitors with improved therapeutic properties.
* **Investigating the therapeutic potential of HDAC inhibition:** Studies using L-687,781 have provided valuable insights into the potential of HDAC inhibitors in treating a variety of diseases.

In summary, L-687,781 is a significant research tool that has contributed to a deeper understanding of HDAC biology and its implications in human health. Its selectivity, potency, and cell-permeability make it an important compound for studying HDAC inhibition and its therapeutic potential in various diseases.