CAS: 37051-38-0

(4-Iodophenyl)acetyl choride is a halogenating agent that has been shown to be effective in the preparation of 4-iodo-cholesterol and sitosterol. This reaction proceeds by way of a free radical mechanism. The addition of the halogen leads to formation of the corresponding alkylating agent, which reacts with the double bond at the 3 position of the sterol ring to form an epoxide intermediate. The epoxide then undergoes hydrolysis and subsequent cyclization, forming the desired product. This reaction is selective for sterols with a side chain at position 3, such as campesterol or cholesterol.